Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/mm/vmscan.c |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds |
| 5 | * |
| 6 | * Swap reorganised 29.12.95, Stephen Tweedie. |
| 7 | * kswapd added: 7.1.96 sct |
| 8 | * Removed kswapd_ctl limits, and swap out as many pages as needed |
| 9 | * to bring the system back to freepages.high: 2.4.97, Rik van Riel. |
| 10 | * Zone aware kswapd started 02/00, Kanoj Sarcar (kanoj@sgi.com). |
| 11 | * Multiqueue VM started 5.8.00, Rik van Riel. |
| 12 | */ |
| 13 | |
| 14 | #include <linux/mm.h> |
| 15 | #include <linux/module.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 16 | #include <linux/gfp.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | #include <linux/kernel_stat.h> |
| 18 | #include <linux/swap.h> |
| 19 | #include <linux/pagemap.h> |
| 20 | #include <linux/init.h> |
| 21 | #include <linux/highmem.h> |
Anton Vorontsov | 70ddf63 | 2013-04-29 15:08:31 -0700 | [diff] [blame] | 22 | #include <linux/vmpressure.h> |
Andrew Morton | e129b5c | 2006-09-27 01:50:00 -0700 | [diff] [blame] | 23 | #include <linux/vmstat.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 24 | #include <linux/file.h> |
| 25 | #include <linux/writeback.h> |
| 26 | #include <linux/blkdev.h> |
| 27 | #include <linux/buffer_head.h> /* for try_to_release_page(), |
| 28 | buffer_heads_over_limit */ |
| 29 | #include <linux/mm_inline.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | #include <linux/backing-dev.h> |
| 31 | #include <linux/rmap.h> |
| 32 | #include <linux/topology.h> |
| 33 | #include <linux/cpu.h> |
| 34 | #include <linux/cpuset.h> |
Mel Gorman | 3e7d344 | 2011-01-13 15:45:56 -0800 | [diff] [blame] | 35 | #include <linux/compaction.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | #include <linux/notifier.h> |
| 37 | #include <linux/rwsem.h> |
Rafael J. Wysocki | 248a030 | 2006-03-22 00:09:04 -0800 | [diff] [blame] | 38 | #include <linux/delay.h> |
Yasunori Goto | 3218ae1 | 2006-06-27 02:53:33 -0700 | [diff] [blame] | 39 | #include <linux/kthread.h> |
Nigel Cunningham | 7dfb710 | 2006-12-06 20:34:23 -0800 | [diff] [blame] | 40 | #include <linux/freezer.h> |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 41 | #include <linux/memcontrol.h> |
Keika Kobayashi | 873b477 | 2008-07-25 01:48:52 -0700 | [diff] [blame] | 42 | #include <linux/delayacct.h> |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 43 | #include <linux/sysctl.h> |
KOSAKI Motohiro | 929bea7 | 2011-04-14 15:22:12 -0700 | [diff] [blame] | 44 | #include <linux/oom.h> |
Linus Torvalds | 268bb0c | 2011-05-20 12:50:29 -0700 | [diff] [blame] | 45 | #include <linux/prefetch.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 46 | |
| 47 | #include <asm/tlbflush.h> |
| 48 | #include <asm/div64.h> |
| 49 | |
| 50 | #include <linux/swapops.h> |
Rafael Aquini | 117aad1 | 2013-09-30 13:45:16 -0700 | [diff] [blame] | 51 | #include <linux/balloon_compaction.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 52 | |
Nick Piggin | 0f8053a | 2006-03-22 00:08:33 -0800 | [diff] [blame] | 53 | #include "internal.h" |
| 54 | |
Mel Gorman | 33906bc | 2010-08-09 17:19:16 -0700 | [diff] [blame] | 55 | #define CREATE_TRACE_POINTS |
| 56 | #include <trace/events/vmscan.h> |
| 57 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 58 | struct scan_control { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 59 | /* Incremented by the number of inactive pages that were scanned */ |
| 60 | unsigned long nr_scanned; |
| 61 | |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 62 | /* Number of pages freed so far during a call to shrink_zones() */ |
| 63 | unsigned long nr_reclaimed; |
| 64 | |
KOSAKI Motohiro | 22fba33 | 2009-12-14 17:59:10 -0800 | [diff] [blame] | 65 | /* How many pages shrink_list() should reclaim */ |
| 66 | unsigned long nr_to_reclaim; |
| 67 | |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame] | 68 | unsigned long hibernation_mode; |
| 69 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 70 | /* This context's GFP mask */ |
Al Viro | 6daa0e2 | 2005-10-21 03:18:50 -0400 | [diff] [blame] | 71 | gfp_t gfp_mask; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 72 | |
| 73 | int may_writepage; |
| 74 | |
Johannes Weiner | a6dc60f8 | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 75 | /* Can mapped pages be reclaimed? */ |
| 76 | int may_unmap; |
Christoph Lameter | f1fd106 | 2006-01-18 17:42:30 -0800 | [diff] [blame] | 77 | |
KOSAKI Motohiro | 2e2e425 | 2009-04-21 12:24:57 -0700 | [diff] [blame] | 78 | /* Can pages be swapped as part of reclaim? */ |
| 79 | int may_swap; |
| 80 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 81 | int order; |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 82 | |
Konstantin Khlebnikov | 9e3b2f8 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 83 | /* Scan (total_size >> priority) pages at once */ |
| 84 | int priority; |
| 85 | |
KOSAKI Motohiro | 5f53e76 | 2010-05-24 14:32:37 -0700 | [diff] [blame] | 86 | /* |
Johannes Weiner | f16015f | 2012-01-12 17:17:52 -0800 | [diff] [blame] | 87 | * The memory cgroup that hit its limit and as a result is the |
| 88 | * primary target of this reclaim invocation. |
| 89 | */ |
| 90 | struct mem_cgroup *target_mem_cgroup; |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 91 | |
KAMEZAWA Hiroyuki | 327c0e9 | 2009-03-31 15:23:31 -0700 | [diff] [blame] | 92 | /* |
| 93 | * Nodemask of nodes allowed by the caller. If NULL, all nodes |
| 94 | * are scanned. |
| 95 | */ |
| 96 | nodemask_t *nodemask; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 97 | }; |
| 98 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 99 | #define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru)) |
| 100 | |
| 101 | #ifdef ARCH_HAS_PREFETCH |
| 102 | #define prefetch_prev_lru_page(_page, _base, _field) \ |
| 103 | do { \ |
| 104 | if ((_page)->lru.prev != _base) { \ |
| 105 | struct page *prev; \ |
| 106 | \ |
| 107 | prev = lru_to_page(&(_page->lru)); \ |
| 108 | prefetch(&prev->_field); \ |
| 109 | } \ |
| 110 | } while (0) |
| 111 | #else |
| 112 | #define prefetch_prev_lru_page(_page, _base, _field) do { } while (0) |
| 113 | #endif |
| 114 | |
| 115 | #ifdef ARCH_HAS_PREFETCHW |
| 116 | #define prefetchw_prev_lru_page(_page, _base, _field) \ |
| 117 | do { \ |
| 118 | if ((_page)->lru.prev != _base) { \ |
| 119 | struct page *prev; \ |
| 120 | \ |
| 121 | prev = lru_to_page(&(_page->lru)); \ |
| 122 | prefetchw(&prev->_field); \ |
| 123 | } \ |
| 124 | } while (0) |
| 125 | #else |
| 126 | #define prefetchw_prev_lru_page(_page, _base, _field) do { } while (0) |
| 127 | #endif |
| 128 | |
| 129 | /* |
| 130 | * From 0 .. 100. Higher means more swappy. |
| 131 | */ |
| 132 | int vm_swappiness = 60; |
Zhang Yanfei | b21e0b9 | 2013-02-22 16:35:48 -0800 | [diff] [blame] | 133 | unsigned long vm_total_pages; /* The total number of pages which the VM controls */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 134 | |
| 135 | static LIST_HEAD(shrinker_list); |
| 136 | static DECLARE_RWSEM(shrinker_rwsem); |
| 137 | |
Andrew Morton | c255a45 | 2012-07-31 16:43:02 -0700 | [diff] [blame] | 138 | #ifdef CONFIG_MEMCG |
Johannes Weiner | 89b5fae | 2012-01-12 17:17:50 -0800 | [diff] [blame] | 139 | static bool global_reclaim(struct scan_control *sc) |
| 140 | { |
Johannes Weiner | f16015f | 2012-01-12 17:17:52 -0800 | [diff] [blame] | 141 | return !sc->target_mem_cgroup; |
Johannes Weiner | 89b5fae | 2012-01-12 17:17:50 -0800 | [diff] [blame] | 142 | } |
KAMEZAWA Hiroyuki | 91a4547 | 2008-02-07 00:14:29 -0800 | [diff] [blame] | 143 | #else |
Johannes Weiner | 89b5fae | 2012-01-12 17:17:50 -0800 | [diff] [blame] | 144 | static bool global_reclaim(struct scan_control *sc) |
| 145 | { |
| 146 | return true; |
| 147 | } |
KAMEZAWA Hiroyuki | 91a4547 | 2008-02-07 00:14:29 -0800 | [diff] [blame] | 148 | #endif |
| 149 | |
Johannes Weiner | a1c3bfb | 2014-01-29 14:05:41 -0800 | [diff] [blame] | 150 | static unsigned long zone_reclaimable_pages(struct zone *zone) |
Lisa Du | 6e543d5 | 2013-09-11 14:22:36 -0700 | [diff] [blame] | 151 | { |
| 152 | int nr; |
| 153 | |
| 154 | nr = zone_page_state(zone, NR_ACTIVE_FILE) + |
| 155 | zone_page_state(zone, NR_INACTIVE_FILE); |
| 156 | |
| 157 | if (get_nr_swap_pages() > 0) |
| 158 | nr += zone_page_state(zone, NR_ACTIVE_ANON) + |
| 159 | zone_page_state(zone, NR_INACTIVE_ANON); |
| 160 | |
| 161 | return nr; |
| 162 | } |
| 163 | |
| 164 | bool zone_reclaimable(struct zone *zone) |
| 165 | { |
| 166 | return zone->pages_scanned < zone_reclaimable_pages(zone) * 6; |
| 167 | } |
| 168 | |
Hugh Dickins | 4d7dcca | 2012-05-29 15:07:08 -0700 | [diff] [blame] | 169 | static unsigned long get_lru_size(struct lruvec *lruvec, enum lru_list lru) |
KOSAKI Motohiro | c9f299d | 2009-01-07 18:08:16 -0800 | [diff] [blame] | 170 | { |
Hugh Dickins | c3c787e | 2012-05-29 15:06:52 -0700 | [diff] [blame] | 171 | if (!mem_cgroup_disabled()) |
Hugh Dickins | 4d7dcca | 2012-05-29 15:07:08 -0700 | [diff] [blame] | 172 | return mem_cgroup_get_lru_size(lruvec, lru); |
KOSAKI Motohiro | a3d8e05 | 2009-01-07 18:08:19 -0800 | [diff] [blame] | 173 | |
Konstantin Khlebnikov | 074291f | 2012-05-29 15:07:00 -0700 | [diff] [blame] | 174 | return zone_page_state(lruvec_zone(lruvec), NR_LRU_BASE + lru); |
KOSAKI Motohiro | c9f299d | 2009-01-07 18:08:16 -0800 | [diff] [blame] | 175 | } |
| 176 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 177 | /* |
Glauber Costa | 1d3d443 | 2013-08-28 10:18:04 +1000 | [diff] [blame] | 178 | * Add a shrinker callback to be called from the vm. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 179 | */ |
Glauber Costa | 1d3d443 | 2013-08-28 10:18:04 +1000 | [diff] [blame] | 180 | int register_shrinker(struct shrinker *shrinker) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 181 | { |
Glauber Costa | 1d3d443 | 2013-08-28 10:18:04 +1000 | [diff] [blame] | 182 | size_t size = sizeof(*shrinker->nr_deferred); |
| 183 | |
| 184 | /* |
| 185 | * If we only have one possible node in the system anyway, save |
| 186 | * ourselves the trouble and disable NUMA aware behavior. This way we |
| 187 | * will save memory and some small loop time later. |
| 188 | */ |
| 189 | if (nr_node_ids == 1) |
| 190 | shrinker->flags &= ~SHRINKER_NUMA_AWARE; |
| 191 | |
| 192 | if (shrinker->flags & SHRINKER_NUMA_AWARE) |
| 193 | size *= nr_node_ids; |
| 194 | |
| 195 | shrinker->nr_deferred = kzalloc(size, GFP_KERNEL); |
| 196 | if (!shrinker->nr_deferred) |
| 197 | return -ENOMEM; |
| 198 | |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 199 | down_write(&shrinker_rwsem); |
| 200 | list_add_tail(&shrinker->list, &shrinker_list); |
| 201 | up_write(&shrinker_rwsem); |
Glauber Costa | 1d3d443 | 2013-08-28 10:18:04 +1000 | [diff] [blame] | 202 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 203 | } |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 204 | EXPORT_SYMBOL(register_shrinker); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 205 | |
| 206 | /* |
| 207 | * Remove one |
| 208 | */ |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 209 | void unregister_shrinker(struct shrinker *shrinker) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 210 | { |
| 211 | down_write(&shrinker_rwsem); |
| 212 | list_del(&shrinker->list); |
| 213 | up_write(&shrinker_rwsem); |
Andrew Vagin | ae39332 | 2013-10-16 13:46:46 -0700 | [diff] [blame] | 214 | kfree(shrinker->nr_deferred); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 215 | } |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 216 | EXPORT_SYMBOL(unregister_shrinker); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 217 | |
| 218 | #define SHRINK_BATCH 128 |
Glauber Costa | 1d3d443 | 2013-08-28 10:18:04 +1000 | [diff] [blame] | 219 | |
| 220 | static unsigned long |
| 221 | shrink_slab_node(struct shrink_control *shrinkctl, struct shrinker *shrinker, |
| 222 | unsigned long nr_pages_scanned, unsigned long lru_pages) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 223 | { |
Glauber Costa | 1d3d443 | 2013-08-28 10:18:04 +1000 | [diff] [blame] | 224 | unsigned long freed = 0; |
| 225 | unsigned long long delta; |
| 226 | long total_scan; |
Vladimir Davydov | d5bc5fd | 2014-04-03 14:47:32 -0700 | [diff] [blame] | 227 | long freeable; |
Glauber Costa | 1d3d443 | 2013-08-28 10:18:04 +1000 | [diff] [blame] | 228 | long nr; |
| 229 | long new_nr; |
| 230 | int nid = shrinkctl->nid; |
| 231 | long batch_size = shrinker->batch ? shrinker->batch |
| 232 | : SHRINK_BATCH; |
| 233 | |
Vladimir Davydov | d5bc5fd | 2014-04-03 14:47:32 -0700 | [diff] [blame] | 234 | freeable = shrinker->count_objects(shrinker, shrinkctl); |
| 235 | if (freeable == 0) |
Glauber Costa | 1d3d443 | 2013-08-28 10:18:04 +1000 | [diff] [blame] | 236 | return 0; |
| 237 | |
| 238 | /* |
| 239 | * copy the current shrinker scan count into a local variable |
| 240 | * and zero it so that other concurrent shrinker invocations |
| 241 | * don't also do this scanning work. |
| 242 | */ |
| 243 | nr = atomic_long_xchg(&shrinker->nr_deferred[nid], 0); |
| 244 | |
| 245 | total_scan = nr; |
| 246 | delta = (4 * nr_pages_scanned) / shrinker->seeks; |
Vladimir Davydov | d5bc5fd | 2014-04-03 14:47:32 -0700 | [diff] [blame] | 247 | delta *= freeable; |
Glauber Costa | 1d3d443 | 2013-08-28 10:18:04 +1000 | [diff] [blame] | 248 | do_div(delta, lru_pages + 1); |
| 249 | total_scan += delta; |
| 250 | if (total_scan < 0) { |
| 251 | printk(KERN_ERR |
| 252 | "shrink_slab: %pF negative objects to delete nr=%ld\n", |
Dave Chinner | a0b0213 | 2013-08-28 10:18:16 +1000 | [diff] [blame] | 253 | shrinker->scan_objects, total_scan); |
Vladimir Davydov | d5bc5fd | 2014-04-03 14:47:32 -0700 | [diff] [blame] | 254 | total_scan = freeable; |
Glauber Costa | 1d3d443 | 2013-08-28 10:18:04 +1000 | [diff] [blame] | 255 | } |
| 256 | |
| 257 | /* |
| 258 | * We need to avoid excessive windup on filesystem shrinkers |
| 259 | * due to large numbers of GFP_NOFS allocations causing the |
| 260 | * shrinkers to return -1 all the time. This results in a large |
| 261 | * nr being built up so when a shrink that can do some work |
| 262 | * comes along it empties the entire cache due to nr >>> |
Vladimir Davydov | d5bc5fd | 2014-04-03 14:47:32 -0700 | [diff] [blame] | 263 | * freeable. This is bad for sustaining a working set in |
Glauber Costa | 1d3d443 | 2013-08-28 10:18:04 +1000 | [diff] [blame] | 264 | * memory. |
| 265 | * |
| 266 | * Hence only allow the shrinker to scan the entire cache when |
| 267 | * a large delta change is calculated directly. |
| 268 | */ |
Vladimir Davydov | d5bc5fd | 2014-04-03 14:47:32 -0700 | [diff] [blame] | 269 | if (delta < freeable / 4) |
| 270 | total_scan = min(total_scan, freeable / 2); |
Glauber Costa | 1d3d443 | 2013-08-28 10:18:04 +1000 | [diff] [blame] | 271 | |
| 272 | /* |
| 273 | * Avoid risking looping forever due to too large nr value: |
| 274 | * never try to free more than twice the estimate number of |
| 275 | * freeable entries. |
| 276 | */ |
Vladimir Davydov | d5bc5fd | 2014-04-03 14:47:32 -0700 | [diff] [blame] | 277 | if (total_scan > freeable * 2) |
| 278 | total_scan = freeable * 2; |
Glauber Costa | 1d3d443 | 2013-08-28 10:18:04 +1000 | [diff] [blame] | 279 | |
| 280 | trace_mm_shrink_slab_start(shrinker, shrinkctl, nr, |
| 281 | nr_pages_scanned, lru_pages, |
Vladimir Davydov | d5bc5fd | 2014-04-03 14:47:32 -0700 | [diff] [blame] | 282 | freeable, delta, total_scan); |
Glauber Costa | 1d3d443 | 2013-08-28 10:18:04 +1000 | [diff] [blame] | 283 | |
Vladimir Davydov | 0b1fb40 | 2014-01-23 15:53:22 -0800 | [diff] [blame] | 284 | /* |
| 285 | * Normally, we should not scan less than batch_size objects in one |
| 286 | * pass to avoid too frequent shrinker calls, but if the slab has less |
| 287 | * than batch_size objects in total and we are really tight on memory, |
| 288 | * we will try to reclaim all available objects, otherwise we can end |
| 289 | * up failing allocations although there are plenty of reclaimable |
| 290 | * objects spread over several slabs with usage less than the |
| 291 | * batch_size. |
| 292 | * |
| 293 | * We detect the "tight on memory" situations by looking at the total |
| 294 | * number of objects we want to scan (total_scan). If it is greater |
Vladimir Davydov | d5bc5fd | 2014-04-03 14:47:32 -0700 | [diff] [blame] | 295 | * than the total number of objects on slab (freeable), we must be |
Vladimir Davydov | 0b1fb40 | 2014-01-23 15:53:22 -0800 | [diff] [blame] | 296 | * scanning at high prio and therefore should try to reclaim as much as |
| 297 | * possible. |
| 298 | */ |
| 299 | while (total_scan >= batch_size || |
Vladimir Davydov | d5bc5fd | 2014-04-03 14:47:32 -0700 | [diff] [blame] | 300 | total_scan >= freeable) { |
Dave Chinner | a0b0213 | 2013-08-28 10:18:16 +1000 | [diff] [blame] | 301 | unsigned long ret; |
Vladimir Davydov | 0b1fb40 | 2014-01-23 15:53:22 -0800 | [diff] [blame] | 302 | unsigned long nr_to_scan = min(batch_size, total_scan); |
Glauber Costa | 1d3d443 | 2013-08-28 10:18:04 +1000 | [diff] [blame] | 303 | |
Vladimir Davydov | 0b1fb40 | 2014-01-23 15:53:22 -0800 | [diff] [blame] | 304 | shrinkctl->nr_to_scan = nr_to_scan; |
Dave Chinner | a0b0213 | 2013-08-28 10:18:16 +1000 | [diff] [blame] | 305 | ret = shrinker->scan_objects(shrinker, shrinkctl); |
| 306 | if (ret == SHRINK_STOP) |
| 307 | break; |
| 308 | freed += ret; |
Glauber Costa | 1d3d443 | 2013-08-28 10:18:04 +1000 | [diff] [blame] | 309 | |
Vladimir Davydov | 0b1fb40 | 2014-01-23 15:53:22 -0800 | [diff] [blame] | 310 | count_vm_events(SLABS_SCANNED, nr_to_scan); |
| 311 | total_scan -= nr_to_scan; |
Glauber Costa | 1d3d443 | 2013-08-28 10:18:04 +1000 | [diff] [blame] | 312 | |
| 313 | cond_resched(); |
| 314 | } |
| 315 | |
| 316 | /* |
| 317 | * move the unused scan count back into the shrinker in a |
| 318 | * manner that handles concurrent updates. If we exhausted the |
| 319 | * scan, there is no need to do an update. |
| 320 | */ |
| 321 | if (total_scan > 0) |
| 322 | new_nr = atomic_long_add_return(total_scan, |
| 323 | &shrinker->nr_deferred[nid]); |
| 324 | else |
| 325 | new_nr = atomic_long_read(&shrinker->nr_deferred[nid]); |
| 326 | |
| 327 | trace_mm_shrink_slab_end(shrinker, freed, nr, new_nr); |
| 328 | return freed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 329 | } |
| 330 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 331 | /* |
| 332 | * Call the shrink functions to age shrinkable caches |
| 333 | * |
| 334 | * Here we assume it costs one seek to replace a lru page and that it also |
| 335 | * takes a seek to recreate a cache object. With this in mind we age equal |
| 336 | * percentages of the lru and ageable caches. This should balance the seeks |
| 337 | * generated by these structures. |
| 338 | * |
Simon Arlott | 183ff22 | 2007-10-20 01:27:18 +0200 | [diff] [blame] | 339 | * If the vm encountered mapped pages on the LRU it increase the pressure on |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 340 | * slab to avoid swapping. |
| 341 | * |
| 342 | * We do weird things to avoid (scanned*seeks*entries) overflowing 32 bits. |
| 343 | * |
| 344 | * `lru_pages' represents the number of on-LRU pages in all the zones which |
| 345 | * are eligible for the caller's allocation attempt. It is used for balancing |
| 346 | * slab reclaim versus page reclaim. |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 347 | * |
| 348 | * Returns the number of slab objects which we shrunk. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 349 | */ |
Dave Chinner | 24f7c6b | 2013-08-28 10:17:56 +1000 | [diff] [blame] | 350 | unsigned long shrink_slab(struct shrink_control *shrinkctl, |
Ying Han | 1495f23 | 2011-05-24 17:12:27 -0700 | [diff] [blame] | 351 | unsigned long nr_pages_scanned, |
Ying Han | a09ed5e | 2011-05-24 17:12:26 -0700 | [diff] [blame] | 352 | unsigned long lru_pages) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 353 | { |
| 354 | struct shrinker *shrinker; |
Dave Chinner | 24f7c6b | 2013-08-28 10:17:56 +1000 | [diff] [blame] | 355 | unsigned long freed = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 356 | |
Ying Han | 1495f23 | 2011-05-24 17:12:27 -0700 | [diff] [blame] | 357 | if (nr_pages_scanned == 0) |
| 358 | nr_pages_scanned = SWAP_CLUSTER_MAX; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 359 | |
Minchan Kim | f06590b | 2011-05-24 17:11:11 -0700 | [diff] [blame] | 360 | if (!down_read_trylock(&shrinker_rwsem)) { |
Dave Chinner | 24f7c6b | 2013-08-28 10:17:56 +1000 | [diff] [blame] | 361 | /* |
| 362 | * If we would return 0, our callers would understand that we |
| 363 | * have nothing else to shrink and give up trying. By returning |
| 364 | * 1 we keep it going and assume we'll be able to shrink next |
| 365 | * time. |
| 366 | */ |
| 367 | freed = 1; |
Minchan Kim | f06590b | 2011-05-24 17:11:11 -0700 | [diff] [blame] | 368 | goto out; |
| 369 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 370 | |
| 371 | list_for_each_entry(shrinker, &shrinker_list, list) { |
Vladimir Davydov | ec97097 | 2014-01-23 15:53:23 -0800 | [diff] [blame] | 372 | if (!(shrinker->flags & SHRINKER_NUMA_AWARE)) { |
| 373 | shrinkctl->nid = 0; |
Glauber Costa | 1d3d443 | 2013-08-28 10:18:04 +1000 | [diff] [blame] | 374 | freed += shrink_slab_node(shrinkctl, shrinker, |
Vladimir Davydov | ec97097 | 2014-01-23 15:53:23 -0800 | [diff] [blame] | 375 | nr_pages_scanned, lru_pages); |
| 376 | continue; |
| 377 | } |
| 378 | |
| 379 | for_each_node_mask(shrinkctl->nid, shrinkctl->nodes_to_scan) { |
| 380 | if (node_online(shrinkctl->nid)) |
| 381 | freed += shrink_slab_node(shrinkctl, shrinker, |
| 382 | nr_pages_scanned, lru_pages); |
Dave Chinner | acf92b4 | 2011-07-08 14:14:35 +1000 | [diff] [blame] | 383 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 384 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 385 | } |
| 386 | up_read(&shrinker_rwsem); |
Minchan Kim | f06590b | 2011-05-24 17:11:11 -0700 | [diff] [blame] | 387 | out: |
| 388 | cond_resched(); |
Dave Chinner | 24f7c6b | 2013-08-28 10:17:56 +1000 | [diff] [blame] | 389 | return freed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 390 | } |
| 391 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 392 | static inline int is_page_cache_freeable(struct page *page) |
| 393 | { |
Johannes Weiner | ceddc3a | 2009-09-21 17:03:00 -0700 | [diff] [blame] | 394 | /* |
| 395 | * A freeable page cache page is referenced only by the caller |
| 396 | * that isolated the page, the page cache radix tree and |
| 397 | * optional buffer heads at page->private. |
| 398 | */ |
Johannes Weiner | edcf474 | 2009-09-21 17:02:59 -0700 | [diff] [blame] | 399 | return page_count(page) - page_has_private(page) == 2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 400 | } |
| 401 | |
KOSAKI Motohiro | 7d3579e | 2010-10-26 14:21:42 -0700 | [diff] [blame] | 402 | static int may_write_to_queue(struct backing_dev_info *bdi, |
| 403 | struct scan_control *sc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 404 | { |
Christoph Lameter | 930d915 | 2006-01-08 01:00:47 -0800 | [diff] [blame] | 405 | if (current->flags & PF_SWAPWRITE) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 406 | return 1; |
| 407 | if (!bdi_write_congested(bdi)) |
| 408 | return 1; |
| 409 | if (bdi == current->backing_dev_info) |
| 410 | return 1; |
| 411 | return 0; |
| 412 | } |
| 413 | |
| 414 | /* |
| 415 | * We detected a synchronous write error writing a page out. Probably |
| 416 | * -ENOSPC. We need to propagate that into the address_space for a subsequent |
| 417 | * fsync(), msync() or close(). |
| 418 | * |
| 419 | * The tricky part is that after writepage we cannot touch the mapping: nothing |
| 420 | * prevents it from being freed up. But we have a ref on the page and once |
| 421 | * that page is locked, the mapping is pinned. |
| 422 | * |
| 423 | * We're allowed to run sleeping lock_page() here because we know the caller has |
| 424 | * __GFP_FS. |
| 425 | */ |
| 426 | static void handle_write_error(struct address_space *mapping, |
| 427 | struct page *page, int error) |
| 428 | { |
Jens Axboe | 7eaceac | 2011-03-10 08:52:07 +0100 | [diff] [blame] | 429 | lock_page(page); |
Guillaume Chazarain | 3e9f45b | 2007-05-08 00:23:25 -0700 | [diff] [blame] | 430 | if (page_mapping(page) == mapping) |
| 431 | mapping_set_error(mapping, error); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 432 | unlock_page(page); |
| 433 | } |
| 434 | |
Christoph Lameter | 04e62a2 | 2006-06-23 02:03:38 -0700 | [diff] [blame] | 435 | /* possible outcome of pageout() */ |
| 436 | typedef enum { |
| 437 | /* failed to write page out, page is locked */ |
| 438 | PAGE_KEEP, |
| 439 | /* move page to the active list, page is locked */ |
| 440 | PAGE_ACTIVATE, |
| 441 | /* page has been sent to the disk successfully, page is unlocked */ |
| 442 | PAGE_SUCCESS, |
| 443 | /* page is clean and locked */ |
| 444 | PAGE_CLEAN, |
| 445 | } pageout_t; |
| 446 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 447 | /* |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 448 | * pageout is called by shrink_page_list() for each dirty page. |
| 449 | * Calls ->writepage(). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 450 | */ |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 451 | static pageout_t pageout(struct page *page, struct address_space *mapping, |
KOSAKI Motohiro | 7d3579e | 2010-10-26 14:21:42 -0700 | [diff] [blame] | 452 | struct scan_control *sc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 453 | { |
| 454 | /* |
| 455 | * If the page is dirty, only perform writeback if that write |
| 456 | * will be non-blocking. To prevent this allocation from being |
| 457 | * stalled by pagecache activity. But note that there may be |
| 458 | * stalls if we need to run get_block(). We could test |
| 459 | * PagePrivate for that. |
| 460 | * |
Vincent Li | 6aceb53 | 2009-12-14 17:58:49 -0800 | [diff] [blame] | 461 | * If this process is currently in __generic_file_aio_write() against |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 462 | * this page's queue, we can perform writeback even if that |
| 463 | * will block. |
| 464 | * |
| 465 | * If the page is swapcache, write it back even if that would |
| 466 | * block, for some throttling. This happens by accident, because |
| 467 | * swap_backing_dev_info is bust: it doesn't reflect the |
| 468 | * congestion state of the swapdevs. Easy to fix, if needed. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 469 | */ |
| 470 | if (!is_page_cache_freeable(page)) |
| 471 | return PAGE_KEEP; |
| 472 | if (!mapping) { |
| 473 | /* |
| 474 | * Some data journaling orphaned pages can have |
| 475 | * page->mapping == NULL while being dirty with clean buffers. |
| 476 | */ |
David Howells | 266cf65 | 2009-04-03 16:42:36 +0100 | [diff] [blame] | 477 | if (page_has_private(page)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 478 | if (try_to_free_buffers(page)) { |
| 479 | ClearPageDirty(page); |
Harvey Harrison | d40cee2 | 2008-04-30 00:55:07 -0700 | [diff] [blame] | 480 | printk("%s: orphaned page\n", __func__); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 481 | return PAGE_CLEAN; |
| 482 | } |
| 483 | } |
| 484 | return PAGE_KEEP; |
| 485 | } |
| 486 | if (mapping->a_ops->writepage == NULL) |
| 487 | return PAGE_ACTIVATE; |
Mel Gorman | 0e093d99 | 2010-10-26 14:21:45 -0700 | [diff] [blame] | 488 | if (!may_write_to_queue(mapping->backing_dev_info, sc)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 489 | return PAGE_KEEP; |
| 490 | |
| 491 | if (clear_page_dirty_for_io(page)) { |
| 492 | int res; |
| 493 | struct writeback_control wbc = { |
| 494 | .sync_mode = WB_SYNC_NONE, |
| 495 | .nr_to_write = SWAP_CLUSTER_MAX, |
OGAWA Hirofumi | 111ebb6 | 2006-06-23 02:03:26 -0700 | [diff] [blame] | 496 | .range_start = 0, |
| 497 | .range_end = LLONG_MAX, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 498 | .for_reclaim = 1, |
| 499 | }; |
| 500 | |
| 501 | SetPageReclaim(page); |
| 502 | res = mapping->a_ops->writepage(page, &wbc); |
| 503 | if (res < 0) |
| 504 | handle_write_error(mapping, page, res); |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 505 | if (res == AOP_WRITEPAGE_ACTIVATE) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 506 | ClearPageReclaim(page); |
| 507 | return PAGE_ACTIVATE; |
| 508 | } |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 509 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 510 | if (!PageWriteback(page)) { |
| 511 | /* synchronous write or broken a_ops? */ |
| 512 | ClearPageReclaim(page); |
| 513 | } |
Mel Gorman | 23b9da5 | 2012-05-29 15:06:20 -0700 | [diff] [blame] | 514 | trace_mm_vmscan_writepage(page, trace_reclaim_flags(page)); |
Andrew Morton | e129b5c | 2006-09-27 01:50:00 -0700 | [diff] [blame] | 515 | inc_zone_page_state(page, NR_VMSCAN_WRITE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 516 | return PAGE_SUCCESS; |
| 517 | } |
| 518 | |
| 519 | return PAGE_CLEAN; |
| 520 | } |
| 521 | |
Andrew Morton | a649fd9 | 2006-10-17 00:09:36 -0700 | [diff] [blame] | 522 | /* |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 523 | * Same as remove_mapping, but if the page is removed from the mapping, it |
| 524 | * gets returned with a refcount of 0. |
Andrew Morton | a649fd9 | 2006-10-17 00:09:36 -0700 | [diff] [blame] | 525 | */ |
Johannes Weiner | a528910 | 2014-04-03 14:47:51 -0700 | [diff] [blame] | 526 | static int __remove_mapping(struct address_space *mapping, struct page *page, |
| 527 | bool reclaimed) |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 528 | { |
Nick Piggin | 28e4d96 | 2006-09-25 23:31:23 -0700 | [diff] [blame] | 529 | BUG_ON(!PageLocked(page)); |
| 530 | BUG_ON(mapping != page_mapping(page)); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 531 | |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 532 | spin_lock_irq(&mapping->tree_lock); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 533 | /* |
Nick Piggin | 0fd0e6b | 2006-09-27 01:50:02 -0700 | [diff] [blame] | 534 | * The non racy check for a busy page. |
| 535 | * |
| 536 | * Must be careful with the order of the tests. When someone has |
| 537 | * a ref to the page, it may be possible that they dirty it then |
| 538 | * drop the reference. So if PageDirty is tested before page_count |
| 539 | * here, then the following race may occur: |
| 540 | * |
| 541 | * get_user_pages(&page); |
| 542 | * [user mapping goes away] |
| 543 | * write_to(page); |
| 544 | * !PageDirty(page) [good] |
| 545 | * SetPageDirty(page); |
| 546 | * put_page(page); |
| 547 | * !page_count(page) [good, discard it] |
| 548 | * |
| 549 | * [oops, our write_to data is lost] |
| 550 | * |
| 551 | * Reversing the order of the tests ensures such a situation cannot |
| 552 | * escape unnoticed. The smp_rmb is needed to ensure the page->flags |
| 553 | * load is not satisfied before that of page->_count. |
| 554 | * |
| 555 | * Note that if SetPageDirty is always performed via set_page_dirty, |
| 556 | * and thus under tree_lock, then this ordering is not required. |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 557 | */ |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 558 | if (!page_freeze_refs(page, 2)) |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 559 | goto cannot_free; |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 560 | /* note: atomic_cmpxchg in page_freeze_refs provides the smp_rmb */ |
| 561 | if (unlikely(PageDirty(page))) { |
| 562 | page_unfreeze_refs(page, 2); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 563 | goto cannot_free; |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 564 | } |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 565 | |
| 566 | if (PageSwapCache(page)) { |
| 567 | swp_entry_t swap = { .val = page_private(page) }; |
| 568 | __delete_from_swap_cache(page); |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 569 | spin_unlock_irq(&mapping->tree_lock); |
KAMEZAWA Hiroyuki | cb4b86b | 2009-06-16 15:32:52 -0700 | [diff] [blame] | 570 | swapcache_free(swap, page); |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 571 | } else { |
Linus Torvalds | 6072d13 | 2010-12-01 13:35:19 -0500 | [diff] [blame] | 572 | void (*freepage)(struct page *); |
Johannes Weiner | a528910 | 2014-04-03 14:47:51 -0700 | [diff] [blame] | 573 | void *shadow = NULL; |
Linus Torvalds | 6072d13 | 2010-12-01 13:35:19 -0500 | [diff] [blame] | 574 | |
| 575 | freepage = mapping->a_ops->freepage; |
Johannes Weiner | a528910 | 2014-04-03 14:47:51 -0700 | [diff] [blame] | 576 | /* |
| 577 | * Remember a shadow entry for reclaimed file cache in |
| 578 | * order to detect refaults, thus thrashing, later on. |
| 579 | * |
| 580 | * But don't store shadows in an address space that is |
| 581 | * already exiting. This is not just an optizimation, |
| 582 | * inode reclaim needs to empty out the radix tree or |
| 583 | * the nodes are lost. Don't plant shadows behind its |
| 584 | * back. |
| 585 | */ |
| 586 | if (reclaimed && page_is_file_cache(page) && |
| 587 | !mapping_exiting(mapping)) |
| 588 | shadow = workingset_eviction(mapping, page); |
| 589 | __delete_from_page_cache(page, shadow); |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 590 | spin_unlock_irq(&mapping->tree_lock); |
Daisuke Nishimura | e767e05 | 2009-05-28 14:34:28 -0700 | [diff] [blame] | 591 | mem_cgroup_uncharge_cache_page(page); |
Linus Torvalds | 6072d13 | 2010-12-01 13:35:19 -0500 | [diff] [blame] | 592 | |
| 593 | if (freepage != NULL) |
| 594 | freepage(page); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 595 | } |
| 596 | |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 597 | return 1; |
| 598 | |
| 599 | cannot_free: |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 600 | spin_unlock_irq(&mapping->tree_lock); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 601 | return 0; |
| 602 | } |
| 603 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 604 | /* |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 605 | * Attempt to detach a locked page from its ->mapping. If it is dirty or if |
| 606 | * someone else has a ref on the page, abort and return 0. If it was |
| 607 | * successfully detached, return 1. Assumes the caller has a single ref on |
| 608 | * this page. |
| 609 | */ |
| 610 | int remove_mapping(struct address_space *mapping, struct page *page) |
| 611 | { |
Johannes Weiner | a528910 | 2014-04-03 14:47:51 -0700 | [diff] [blame] | 612 | if (__remove_mapping(mapping, page, false)) { |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 613 | /* |
| 614 | * Unfreezing the refcount with 1 rather than 2 effectively |
| 615 | * drops the pagecache ref for us without requiring another |
| 616 | * atomic operation. |
| 617 | */ |
| 618 | page_unfreeze_refs(page, 1); |
| 619 | return 1; |
| 620 | } |
| 621 | return 0; |
| 622 | } |
| 623 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 624 | /** |
| 625 | * putback_lru_page - put previously isolated page onto appropriate LRU list |
| 626 | * @page: page to be put back to appropriate lru list |
| 627 | * |
| 628 | * Add previously isolated @page to appropriate LRU list. |
| 629 | * Page may still be unevictable for other reasons. |
| 630 | * |
| 631 | * lru_lock must not be held, interrupts must be enabled. |
| 632 | */ |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 633 | void putback_lru_page(struct page *page) |
| 634 | { |
Vlastimil Babka | 0ec3b74 | 2013-09-11 14:22:26 -0700 | [diff] [blame] | 635 | bool is_unevictable; |
Lee Schermerhorn | bbfd28e | 2008-10-18 20:26:40 -0700 | [diff] [blame] | 636 | int was_unevictable = PageUnevictable(page); |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 637 | |
Sasha Levin | 309381fea | 2014-01-23 15:52:54 -0800 | [diff] [blame] | 638 | VM_BUG_ON_PAGE(PageLRU(page), page); |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 639 | |
| 640 | redo: |
| 641 | ClearPageUnevictable(page); |
| 642 | |
Hugh Dickins | 39b5f29 | 2012-10-08 16:33:18 -0700 | [diff] [blame] | 643 | if (page_evictable(page)) { |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 644 | /* |
| 645 | * For evictable pages, we can use the cache. |
| 646 | * In event of a race, worst case is we end up with an |
| 647 | * unevictable page on [in]active list. |
| 648 | * We know how to handle that. |
| 649 | */ |
Vlastimil Babka | 0ec3b74 | 2013-09-11 14:22:26 -0700 | [diff] [blame] | 650 | is_unevictable = false; |
Mel Gorman | c53954a | 2013-07-03 15:02:34 -0700 | [diff] [blame] | 651 | lru_cache_add(page); |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 652 | } else { |
| 653 | /* |
| 654 | * Put unevictable pages directly on zone's unevictable |
| 655 | * list. |
| 656 | */ |
Vlastimil Babka | 0ec3b74 | 2013-09-11 14:22:26 -0700 | [diff] [blame] | 657 | is_unevictable = true; |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 658 | add_page_to_unevictable_list(page); |
Johannes Weiner | 6a7b954 | 2009-10-26 16:50:00 -0700 | [diff] [blame] | 659 | /* |
Minchan Kim | 21ee9f3 | 2011-10-31 17:09:28 -0700 | [diff] [blame] | 660 | * When racing with an mlock or AS_UNEVICTABLE clearing |
| 661 | * (page is unlocked) make sure that if the other thread |
| 662 | * does not observe our setting of PG_lru and fails |
Hugh Dickins | 2451326 | 2012-01-20 14:34:21 -0800 | [diff] [blame] | 663 | * isolation/check_move_unevictable_pages, |
Minchan Kim | 21ee9f3 | 2011-10-31 17:09:28 -0700 | [diff] [blame] | 664 | * we see PG_mlocked/AS_UNEVICTABLE cleared below and move |
Johannes Weiner | 6a7b954 | 2009-10-26 16:50:00 -0700 | [diff] [blame] | 665 | * the page back to the evictable list. |
| 666 | * |
Minchan Kim | 21ee9f3 | 2011-10-31 17:09:28 -0700 | [diff] [blame] | 667 | * The other side is TestClearPageMlocked() or shmem_lock(). |
Johannes Weiner | 6a7b954 | 2009-10-26 16:50:00 -0700 | [diff] [blame] | 668 | */ |
| 669 | smp_mb(); |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 670 | } |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 671 | |
| 672 | /* |
| 673 | * page's status can change while we move it among lru. If an evictable |
| 674 | * page is on unevictable list, it never be freed. To avoid that, |
| 675 | * check after we added it to the list, again. |
| 676 | */ |
Vlastimil Babka | 0ec3b74 | 2013-09-11 14:22:26 -0700 | [diff] [blame] | 677 | if (is_unevictable && page_evictable(page)) { |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 678 | if (!isolate_lru_page(page)) { |
| 679 | put_page(page); |
| 680 | goto redo; |
| 681 | } |
| 682 | /* This means someone else dropped this page from LRU |
| 683 | * So, it will be freed or putback to LRU again. There is |
| 684 | * nothing to do here. |
| 685 | */ |
| 686 | } |
| 687 | |
Vlastimil Babka | 0ec3b74 | 2013-09-11 14:22:26 -0700 | [diff] [blame] | 688 | if (was_unevictable && !is_unevictable) |
Lee Schermerhorn | bbfd28e | 2008-10-18 20:26:40 -0700 | [diff] [blame] | 689 | count_vm_event(UNEVICTABLE_PGRESCUED); |
Vlastimil Babka | 0ec3b74 | 2013-09-11 14:22:26 -0700 | [diff] [blame] | 690 | else if (!was_unevictable && is_unevictable) |
Lee Schermerhorn | bbfd28e | 2008-10-18 20:26:40 -0700 | [diff] [blame] | 691 | count_vm_event(UNEVICTABLE_PGCULLED); |
| 692 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 693 | put_page(page); /* drop ref from isolate */ |
| 694 | } |
| 695 | |
Johannes Weiner | dfc8d63 | 2010-03-05 13:42:19 -0800 | [diff] [blame] | 696 | enum page_references { |
| 697 | PAGEREF_RECLAIM, |
| 698 | PAGEREF_RECLAIM_CLEAN, |
Johannes Weiner | 64574746 | 2010-03-05 13:42:22 -0800 | [diff] [blame] | 699 | PAGEREF_KEEP, |
Johannes Weiner | dfc8d63 | 2010-03-05 13:42:19 -0800 | [diff] [blame] | 700 | PAGEREF_ACTIVATE, |
| 701 | }; |
| 702 | |
| 703 | static enum page_references page_check_references(struct page *page, |
| 704 | struct scan_control *sc) |
| 705 | { |
Johannes Weiner | 64574746 | 2010-03-05 13:42:22 -0800 | [diff] [blame] | 706 | int referenced_ptes, referenced_page; |
Johannes Weiner | dfc8d63 | 2010-03-05 13:42:19 -0800 | [diff] [blame] | 707 | unsigned long vm_flags; |
Johannes Weiner | dfc8d63 | 2010-03-05 13:42:19 -0800 | [diff] [blame] | 708 | |
Johannes Weiner | c3ac9a8 | 2012-05-29 15:06:25 -0700 | [diff] [blame] | 709 | referenced_ptes = page_referenced(page, 1, sc->target_mem_cgroup, |
| 710 | &vm_flags); |
Johannes Weiner | 64574746 | 2010-03-05 13:42:22 -0800 | [diff] [blame] | 711 | referenced_page = TestClearPageReferenced(page); |
Johannes Weiner | dfc8d63 | 2010-03-05 13:42:19 -0800 | [diff] [blame] | 712 | |
Johannes Weiner | dfc8d63 | 2010-03-05 13:42:19 -0800 | [diff] [blame] | 713 | /* |
| 714 | * Mlock lost the isolation race with us. Let try_to_unmap() |
| 715 | * move the page to the unevictable list. |
| 716 | */ |
| 717 | if (vm_flags & VM_LOCKED) |
| 718 | return PAGEREF_RECLAIM; |
| 719 | |
Johannes Weiner | 64574746 | 2010-03-05 13:42:22 -0800 | [diff] [blame] | 720 | if (referenced_ptes) { |
Michal Hocko | e4898273 | 2012-05-29 15:06:45 -0700 | [diff] [blame] | 721 | if (PageSwapBacked(page)) |
Johannes Weiner | 64574746 | 2010-03-05 13:42:22 -0800 | [diff] [blame] | 722 | return PAGEREF_ACTIVATE; |
| 723 | /* |
| 724 | * All mapped pages start out with page table |
| 725 | * references from the instantiating fault, so we need |
| 726 | * to look twice if a mapped file page is used more |
| 727 | * than once. |
| 728 | * |
| 729 | * Mark it and spare it for another trip around the |
| 730 | * inactive list. Another page table reference will |
| 731 | * lead to its activation. |
| 732 | * |
| 733 | * Note: the mark is set for activated pages as well |
| 734 | * so that recently deactivated but used pages are |
| 735 | * quickly recovered. |
| 736 | */ |
| 737 | SetPageReferenced(page); |
| 738 | |
Konstantin Khlebnikov | 34dbc67 | 2012-01-10 15:06:59 -0800 | [diff] [blame] | 739 | if (referenced_page || referenced_ptes > 1) |
Johannes Weiner | 64574746 | 2010-03-05 13:42:22 -0800 | [diff] [blame] | 740 | return PAGEREF_ACTIVATE; |
| 741 | |
Konstantin Khlebnikov | c909e99 | 2012-01-10 15:07:03 -0800 | [diff] [blame] | 742 | /* |
| 743 | * Activate file-backed executable pages after first usage. |
| 744 | */ |
| 745 | if (vm_flags & VM_EXEC) |
| 746 | return PAGEREF_ACTIVATE; |
| 747 | |
Johannes Weiner | 64574746 | 2010-03-05 13:42:22 -0800 | [diff] [blame] | 748 | return PAGEREF_KEEP; |
| 749 | } |
Johannes Weiner | dfc8d63 | 2010-03-05 13:42:19 -0800 | [diff] [blame] | 750 | |
| 751 | /* Reclaim if clean, defer dirty pages to writeback */ |
KOSAKI Motohiro | 2e30244 | 2010-10-26 14:21:46 -0700 | [diff] [blame] | 752 | if (referenced_page && !PageSwapBacked(page)) |
Johannes Weiner | 64574746 | 2010-03-05 13:42:22 -0800 | [diff] [blame] | 753 | return PAGEREF_RECLAIM_CLEAN; |
| 754 | |
| 755 | return PAGEREF_RECLAIM; |
Johannes Weiner | dfc8d63 | 2010-03-05 13:42:19 -0800 | [diff] [blame] | 756 | } |
| 757 | |
Mel Gorman | e2be15f | 2013-07-03 15:01:57 -0700 | [diff] [blame] | 758 | /* Check if a page is dirty or under writeback */ |
| 759 | static void page_check_dirty_writeback(struct page *page, |
| 760 | bool *dirty, bool *writeback) |
| 761 | { |
Mel Gorman | b459722 | 2013-07-03 15:02:05 -0700 | [diff] [blame] | 762 | struct address_space *mapping; |
| 763 | |
Mel Gorman | e2be15f | 2013-07-03 15:01:57 -0700 | [diff] [blame] | 764 | /* |
| 765 | * Anonymous pages are not handled by flushers and must be written |
| 766 | * from reclaim context. Do not stall reclaim based on them |
| 767 | */ |
| 768 | if (!page_is_file_cache(page)) { |
| 769 | *dirty = false; |
| 770 | *writeback = false; |
| 771 | return; |
| 772 | } |
| 773 | |
| 774 | /* By default assume that the page flags are accurate */ |
| 775 | *dirty = PageDirty(page); |
| 776 | *writeback = PageWriteback(page); |
Mel Gorman | b459722 | 2013-07-03 15:02:05 -0700 | [diff] [blame] | 777 | |
| 778 | /* Verify dirty/writeback state if the filesystem supports it */ |
| 779 | if (!page_has_private(page)) |
| 780 | return; |
| 781 | |
| 782 | mapping = page_mapping(page); |
| 783 | if (mapping && mapping->a_ops->is_dirty_writeback) |
| 784 | mapping->a_ops->is_dirty_writeback(page, dirty, writeback); |
Mel Gorman | e2be15f | 2013-07-03 15:01:57 -0700 | [diff] [blame] | 785 | } |
| 786 | |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 787 | /* |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 788 | * shrink_page_list() returns the number of reclaimed pages |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 789 | */ |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 790 | static unsigned long shrink_page_list(struct list_head *page_list, |
Konstantin Khlebnikov | 6a18adb | 2012-05-29 15:06:59 -0700 | [diff] [blame] | 791 | struct zone *zone, |
Mel Gorman | f84f6e2 | 2011-10-31 17:07:51 -0700 | [diff] [blame] | 792 | struct scan_control *sc, |
Minchan Kim | 02c6de8 | 2012-10-08 16:31:55 -0700 | [diff] [blame] | 793 | enum ttu_flags ttu_flags, |
Mel Gorman | 8e95028 | 2013-07-03 15:02:02 -0700 | [diff] [blame] | 794 | unsigned long *ret_nr_dirty, |
Mel Gorman | d43006d | 2013-07-03 15:01:50 -0700 | [diff] [blame] | 795 | unsigned long *ret_nr_unqueued_dirty, |
Mel Gorman | 8e95028 | 2013-07-03 15:02:02 -0700 | [diff] [blame] | 796 | unsigned long *ret_nr_congested, |
Minchan Kim | 02c6de8 | 2012-10-08 16:31:55 -0700 | [diff] [blame] | 797 | unsigned long *ret_nr_writeback, |
Mel Gorman | b1a6f21 | 2013-07-03 15:01:58 -0700 | [diff] [blame] | 798 | unsigned long *ret_nr_immediate, |
Minchan Kim | 02c6de8 | 2012-10-08 16:31:55 -0700 | [diff] [blame] | 799 | bool force_reclaim) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 800 | { |
| 801 | LIST_HEAD(ret_pages); |
Mel Gorman | abe4c3b | 2010-08-09 17:19:31 -0700 | [diff] [blame] | 802 | LIST_HEAD(free_pages); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 803 | int pgactivate = 0; |
Mel Gorman | d43006d | 2013-07-03 15:01:50 -0700 | [diff] [blame] | 804 | unsigned long nr_unqueued_dirty = 0; |
Mel Gorman | 0e093d99 | 2010-10-26 14:21:45 -0700 | [diff] [blame] | 805 | unsigned long nr_dirty = 0; |
| 806 | unsigned long nr_congested = 0; |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 807 | unsigned long nr_reclaimed = 0; |
Mel Gorman | 92df3a7 | 2011-10-31 17:07:56 -0700 | [diff] [blame] | 808 | unsigned long nr_writeback = 0; |
Mel Gorman | b1a6f21 | 2013-07-03 15:01:58 -0700 | [diff] [blame] | 809 | unsigned long nr_immediate = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 810 | |
| 811 | cond_resched(); |
| 812 | |
Tim Chen | 69980e3 | 2012-07-31 16:46:08 -0700 | [diff] [blame] | 813 | mem_cgroup_uncharge_start(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 814 | while (!list_empty(page_list)) { |
| 815 | struct address_space *mapping; |
| 816 | struct page *page; |
| 817 | int may_enter_fs; |
Minchan Kim | 02c6de8 | 2012-10-08 16:31:55 -0700 | [diff] [blame] | 818 | enum page_references references = PAGEREF_RECLAIM_CLEAN; |
Mel Gorman | e2be15f | 2013-07-03 15:01:57 -0700 | [diff] [blame] | 819 | bool dirty, writeback; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 820 | |
| 821 | cond_resched(); |
| 822 | |
| 823 | page = lru_to_page(page_list); |
| 824 | list_del(&page->lru); |
| 825 | |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 826 | if (!trylock_page(page)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 827 | goto keep; |
| 828 | |
Sasha Levin | 309381fea | 2014-01-23 15:52:54 -0800 | [diff] [blame] | 829 | VM_BUG_ON_PAGE(PageActive(page), page); |
| 830 | VM_BUG_ON_PAGE(page_zone(page) != zone, page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 831 | |
| 832 | sc->nr_scanned++; |
Christoph Lameter | 80e4342 | 2006-02-11 17:55:53 -0800 | [diff] [blame] | 833 | |
Hugh Dickins | 39b5f29 | 2012-10-08 16:33:18 -0700 | [diff] [blame] | 834 | if (unlikely(!page_evictable(page))) |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 835 | goto cull_mlocked; |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 836 | |
Johannes Weiner | a6dc60f8 | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 837 | if (!sc->may_unmap && page_mapped(page)) |
Christoph Lameter | 80e4342 | 2006-02-11 17:55:53 -0800 | [diff] [blame] | 838 | goto keep_locked; |
| 839 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 840 | /* Double the slab pressure for mapped and swapcache pages */ |
| 841 | if (page_mapped(page) || PageSwapCache(page)) |
| 842 | sc->nr_scanned++; |
| 843 | |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 844 | may_enter_fs = (sc->gfp_mask & __GFP_FS) || |
| 845 | (PageSwapCache(page) && (sc->gfp_mask & __GFP_IO)); |
| 846 | |
Mel Gorman | 283aba9 | 2013-07-03 15:01:51 -0700 | [diff] [blame] | 847 | /* |
Mel Gorman | e2be15f | 2013-07-03 15:01:57 -0700 | [diff] [blame] | 848 | * The number of dirty pages determines if a zone is marked |
| 849 | * reclaim_congested which affects wait_iff_congested. kswapd |
| 850 | * will stall and start writing pages if the tail of the LRU |
| 851 | * is all dirty unqueued pages. |
| 852 | */ |
| 853 | page_check_dirty_writeback(page, &dirty, &writeback); |
| 854 | if (dirty || writeback) |
| 855 | nr_dirty++; |
| 856 | |
| 857 | if (dirty && !writeback) |
| 858 | nr_unqueued_dirty++; |
| 859 | |
Mel Gorman | d04e8ac | 2013-07-03 15:02:03 -0700 | [diff] [blame] | 860 | /* |
| 861 | * Treat this page as congested if the underlying BDI is or if |
| 862 | * pages are cycling through the LRU so quickly that the |
| 863 | * pages marked for immediate reclaim are making it to the |
| 864 | * end of the LRU a second time. |
| 865 | */ |
Mel Gorman | e2be15f | 2013-07-03 15:01:57 -0700 | [diff] [blame] | 866 | mapping = page_mapping(page); |
Mel Gorman | d04e8ac | 2013-07-03 15:02:03 -0700 | [diff] [blame] | 867 | if ((mapping && bdi_write_congested(mapping->backing_dev_info)) || |
| 868 | (writeback && PageReclaim(page))) |
Mel Gorman | e2be15f | 2013-07-03 15:01:57 -0700 | [diff] [blame] | 869 | nr_congested++; |
| 870 | |
| 871 | /* |
Mel Gorman | 283aba9 | 2013-07-03 15:01:51 -0700 | [diff] [blame] | 872 | * If a page at the tail of the LRU is under writeback, there |
| 873 | * are three cases to consider. |
| 874 | * |
| 875 | * 1) If reclaim is encountering an excessive number of pages |
| 876 | * under writeback and this page is both under writeback and |
| 877 | * PageReclaim then it indicates that pages are being queued |
| 878 | * for IO but are being recycled through the LRU before the |
| 879 | * IO can complete. Waiting on the page itself risks an |
| 880 | * indefinite stall if it is impossible to writeback the |
| 881 | * page due to IO error or disconnected storage so instead |
Mel Gorman | b1a6f21 | 2013-07-03 15:01:58 -0700 | [diff] [blame] | 882 | * note that the LRU is being scanned too quickly and the |
| 883 | * caller can stall after page list has been processed. |
Mel Gorman | 283aba9 | 2013-07-03 15:01:51 -0700 | [diff] [blame] | 884 | * |
| 885 | * 2) Global reclaim encounters a page, memcg encounters a |
| 886 | * page that is not marked for immediate reclaim or |
| 887 | * the caller does not have __GFP_IO. In this case mark |
| 888 | * the page for immediate reclaim and continue scanning. |
| 889 | * |
| 890 | * __GFP_IO is checked because a loop driver thread might |
| 891 | * enter reclaim, and deadlock if it waits on a page for |
| 892 | * which it is needed to do the write (loop masks off |
| 893 | * __GFP_IO|__GFP_FS for this reason); but more thought |
| 894 | * would probably show more reasons. |
| 895 | * |
| 896 | * Don't require __GFP_FS, since we're not going into the |
| 897 | * FS, just waiting on its writeback completion. Worryingly, |
| 898 | * ext4 gfs2 and xfs allocate pages with |
| 899 | * grab_cache_page_write_begin(,,AOP_FLAG_NOFS), so testing |
| 900 | * may_enter_fs here is liable to OOM on them. |
| 901 | * |
| 902 | * 3) memcg encounters a page that is not already marked |
| 903 | * PageReclaim. memcg does not have any dirty pages |
| 904 | * throttling so we could easily OOM just because too many |
| 905 | * pages are in writeback and there is nothing else to |
| 906 | * reclaim. Wait for the writeback to complete. |
| 907 | */ |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 908 | if (PageWriteback(page)) { |
Mel Gorman | 283aba9 | 2013-07-03 15:01:51 -0700 | [diff] [blame] | 909 | /* Case 1 above */ |
| 910 | if (current_is_kswapd() && |
| 911 | PageReclaim(page) && |
| 912 | zone_is_reclaim_writeback(zone)) { |
Mel Gorman | b1a6f21 | 2013-07-03 15:01:58 -0700 | [diff] [blame] | 913 | nr_immediate++; |
| 914 | goto keep_locked; |
Mel Gorman | 283aba9 | 2013-07-03 15:01:51 -0700 | [diff] [blame] | 915 | |
| 916 | /* Case 2 above */ |
| 917 | } else if (global_reclaim(sc) || |
Hugh Dickins | c3b94f4 | 2012-07-31 16:45:59 -0700 | [diff] [blame] | 918 | !PageReclaim(page) || !(sc->gfp_mask & __GFP_IO)) { |
| 919 | /* |
| 920 | * This is slightly racy - end_page_writeback() |
| 921 | * might have just cleared PageReclaim, then |
| 922 | * setting PageReclaim here end up interpreted |
| 923 | * as PageReadahead - but that does not matter |
| 924 | * enough to care. What we do want is for this |
| 925 | * page to have PageReclaim set next time memcg |
| 926 | * reclaim reaches the tests above, so it will |
| 927 | * then wait_on_page_writeback() to avoid OOM; |
| 928 | * and it's also appropriate in global reclaim. |
| 929 | */ |
| 930 | SetPageReclaim(page); |
Michal Hocko | e62e384 | 2012-07-31 16:45:55 -0700 | [diff] [blame] | 931 | nr_writeback++; |
Mel Gorman | 283aba9 | 2013-07-03 15:01:51 -0700 | [diff] [blame] | 932 | |
Hugh Dickins | c3b94f4 | 2012-07-31 16:45:59 -0700 | [diff] [blame] | 933 | goto keep_locked; |
Mel Gorman | 283aba9 | 2013-07-03 15:01:51 -0700 | [diff] [blame] | 934 | |
| 935 | /* Case 3 above */ |
| 936 | } else { |
| 937 | wait_on_page_writeback(page); |
Michal Hocko | e62e384 | 2012-07-31 16:45:55 -0700 | [diff] [blame] | 938 | } |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 939 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 940 | |
Minchan Kim | 02c6de8 | 2012-10-08 16:31:55 -0700 | [diff] [blame] | 941 | if (!force_reclaim) |
| 942 | references = page_check_references(page, sc); |
| 943 | |
Johannes Weiner | dfc8d63 | 2010-03-05 13:42:19 -0800 | [diff] [blame] | 944 | switch (references) { |
| 945 | case PAGEREF_ACTIVATE: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 946 | goto activate_locked; |
Johannes Weiner | 64574746 | 2010-03-05 13:42:22 -0800 | [diff] [blame] | 947 | case PAGEREF_KEEP: |
| 948 | goto keep_locked; |
Johannes Weiner | dfc8d63 | 2010-03-05 13:42:19 -0800 | [diff] [blame] | 949 | case PAGEREF_RECLAIM: |
| 950 | case PAGEREF_RECLAIM_CLEAN: |
| 951 | ; /* try to reclaim the page below */ |
| 952 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 953 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 954 | /* |
| 955 | * Anonymous process memory has backing store? |
| 956 | * Try to allocate it some swap space here. |
| 957 | */ |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 958 | if (PageAnon(page) && !PageSwapCache(page)) { |
Hugh Dickins | 63eb6b9 | 2008-11-19 15:36:37 -0800 | [diff] [blame] | 959 | if (!(sc->gfp_mask & __GFP_IO)) |
| 960 | goto keep_locked; |
Shaohua Li | 5bc7b8a | 2013-04-29 15:08:36 -0700 | [diff] [blame] | 961 | if (!add_to_swap(page, page_list)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 962 | goto activate_locked; |
Hugh Dickins | 63eb6b9 | 2008-11-19 15:36:37 -0800 | [diff] [blame] | 963 | may_enter_fs = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 964 | |
Mel Gorman | e2be15f | 2013-07-03 15:01:57 -0700 | [diff] [blame] | 965 | /* Adding to swap updated mapping */ |
| 966 | mapping = page_mapping(page); |
| 967 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 968 | |
| 969 | /* |
| 970 | * The page is mapped into the page tables of one or more |
| 971 | * processes. Try to unmap it here. |
| 972 | */ |
| 973 | if (page_mapped(page) && mapping) { |
Minchan Kim | 02c6de8 | 2012-10-08 16:31:55 -0700 | [diff] [blame] | 974 | switch (try_to_unmap(page, ttu_flags)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 975 | case SWAP_FAIL: |
| 976 | goto activate_locked; |
| 977 | case SWAP_AGAIN: |
| 978 | goto keep_locked; |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 979 | case SWAP_MLOCK: |
| 980 | goto cull_mlocked; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 981 | case SWAP_SUCCESS: |
| 982 | ; /* try to free the page below */ |
| 983 | } |
| 984 | } |
| 985 | |
| 986 | if (PageDirty(page)) { |
Mel Gorman | ee72886 | 2011-10-31 17:07:38 -0700 | [diff] [blame] | 987 | /* |
| 988 | * Only kswapd can writeback filesystem pages to |
Mel Gorman | d43006d | 2013-07-03 15:01:50 -0700 | [diff] [blame] | 989 | * avoid risk of stack overflow but only writeback |
| 990 | * if many dirty pages have been encountered. |
Mel Gorman | ee72886 | 2011-10-31 17:07:38 -0700 | [diff] [blame] | 991 | */ |
Mel Gorman | f84f6e2 | 2011-10-31 17:07:51 -0700 | [diff] [blame] | 992 | if (page_is_file_cache(page) && |
Konstantin Khlebnikov | 9e3b2f8 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 993 | (!current_is_kswapd() || |
Mel Gorman | d43006d | 2013-07-03 15:01:50 -0700 | [diff] [blame] | 994 | !zone_is_reclaim_dirty(zone))) { |
Mel Gorman | 49ea7eb | 2011-10-31 17:07:59 -0700 | [diff] [blame] | 995 | /* |
| 996 | * Immediately reclaim when written back. |
| 997 | * Similar in principal to deactivate_page() |
| 998 | * except we already have the page isolated |
| 999 | * and know it's dirty |
| 1000 | */ |
| 1001 | inc_zone_page_state(page, NR_VMSCAN_IMMEDIATE); |
| 1002 | SetPageReclaim(page); |
| 1003 | |
Mel Gorman | ee72886 | 2011-10-31 17:07:38 -0700 | [diff] [blame] | 1004 | goto keep_locked; |
| 1005 | } |
| 1006 | |
Johannes Weiner | dfc8d63 | 2010-03-05 13:42:19 -0800 | [diff] [blame] | 1007 | if (references == PAGEREF_RECLAIM_CLEAN) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1008 | goto keep_locked; |
Andrew Morton | 4dd4b92 | 2008-03-24 12:29:52 -0700 | [diff] [blame] | 1009 | if (!may_enter_fs) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1010 | goto keep_locked; |
Christoph Lameter | 52a8363 | 2006-02-01 03:05:28 -0800 | [diff] [blame] | 1011 | if (!sc->may_writepage) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1012 | goto keep_locked; |
| 1013 | |
| 1014 | /* Page is dirty, try to write it out here */ |
KOSAKI Motohiro | 7d3579e | 2010-10-26 14:21:42 -0700 | [diff] [blame] | 1015 | switch (pageout(page, mapping, sc)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1016 | case PAGE_KEEP: |
| 1017 | goto keep_locked; |
| 1018 | case PAGE_ACTIVATE: |
| 1019 | goto activate_locked; |
| 1020 | case PAGE_SUCCESS: |
KOSAKI Motohiro | 7d3579e | 2010-10-26 14:21:42 -0700 | [diff] [blame] | 1021 | if (PageWriteback(page)) |
Mel Gorman | 41ac199 | 2012-05-29 15:06:19 -0700 | [diff] [blame] | 1022 | goto keep; |
KOSAKI Motohiro | 7d3579e | 2010-10-26 14:21:42 -0700 | [diff] [blame] | 1023 | if (PageDirty(page)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1024 | goto keep; |
KOSAKI Motohiro | 7d3579e | 2010-10-26 14:21:42 -0700 | [diff] [blame] | 1025 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1026 | /* |
| 1027 | * A synchronous write - probably a ramdisk. Go |
| 1028 | * ahead and try to reclaim the page. |
| 1029 | */ |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 1030 | if (!trylock_page(page)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1031 | goto keep; |
| 1032 | if (PageDirty(page) || PageWriteback(page)) |
| 1033 | goto keep_locked; |
| 1034 | mapping = page_mapping(page); |
| 1035 | case PAGE_CLEAN: |
| 1036 | ; /* try to free the page below */ |
| 1037 | } |
| 1038 | } |
| 1039 | |
| 1040 | /* |
| 1041 | * If the page has buffers, try to free the buffer mappings |
| 1042 | * associated with this page. If we succeed we try to free |
| 1043 | * the page as well. |
| 1044 | * |
| 1045 | * We do this even if the page is PageDirty(). |
| 1046 | * try_to_release_page() does not perform I/O, but it is |
| 1047 | * possible for a page to have PageDirty set, but it is actually |
| 1048 | * clean (all its buffers are clean). This happens if the |
| 1049 | * buffers were written out directly, with submit_bh(). ext3 |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 1050 | * will do this, as well as the blockdev mapping. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1051 | * try_to_release_page() will discover that cleanness and will |
| 1052 | * drop the buffers and mark the page clean - it can be freed. |
| 1053 | * |
| 1054 | * Rarely, pages can have buffers and no ->mapping. These are |
| 1055 | * the pages which were not successfully invalidated in |
| 1056 | * truncate_complete_page(). We try to drop those buffers here |
| 1057 | * and if that worked, and the page is no longer mapped into |
| 1058 | * process address space (page_count == 1) it can be freed. |
| 1059 | * Otherwise, leave the page on the LRU so it is swappable. |
| 1060 | */ |
David Howells | 266cf65 | 2009-04-03 16:42:36 +0100 | [diff] [blame] | 1061 | if (page_has_private(page)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1062 | if (!try_to_release_page(page, sc->gfp_mask)) |
| 1063 | goto activate_locked; |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 1064 | if (!mapping && page_count(page) == 1) { |
| 1065 | unlock_page(page); |
| 1066 | if (put_page_testzero(page)) |
| 1067 | goto free_it; |
| 1068 | else { |
| 1069 | /* |
| 1070 | * rare race with speculative reference. |
| 1071 | * the speculative reference will free |
| 1072 | * this page shortly, so we may |
| 1073 | * increment nr_reclaimed here (and |
| 1074 | * leave it off the LRU). |
| 1075 | */ |
| 1076 | nr_reclaimed++; |
| 1077 | continue; |
| 1078 | } |
| 1079 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1080 | } |
| 1081 | |
Johannes Weiner | a528910 | 2014-04-03 14:47:51 -0700 | [diff] [blame] | 1082 | if (!mapping || !__remove_mapping(mapping, page, true)) |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 1083 | goto keep_locked; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1084 | |
Nick Piggin | a978d6f | 2008-10-18 20:26:58 -0700 | [diff] [blame] | 1085 | /* |
| 1086 | * At this point, we have no other references and there is |
| 1087 | * no way to pick any more up (removed from LRU, removed |
| 1088 | * from pagecache). Can use non-atomic bitops now (and |
| 1089 | * we obviously don't have to worry about waking up a process |
| 1090 | * waiting on the page lock, because there are no references. |
| 1091 | */ |
| 1092 | __clear_page_locked(page); |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 1093 | free_it: |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1094 | nr_reclaimed++; |
Mel Gorman | abe4c3b | 2010-08-09 17:19:31 -0700 | [diff] [blame] | 1095 | |
| 1096 | /* |
| 1097 | * Is there need to periodically free_page_list? It would |
| 1098 | * appear not as the counts should be low |
| 1099 | */ |
| 1100 | list_add(&page->lru, &free_pages); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1101 | continue; |
| 1102 | |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 1103 | cull_mlocked: |
Hugh Dickins | 63d6c5a | 2009-01-06 14:39:38 -0800 | [diff] [blame] | 1104 | if (PageSwapCache(page)) |
| 1105 | try_to_free_swap(page); |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 1106 | unlock_page(page); |
| 1107 | putback_lru_page(page); |
| 1108 | continue; |
| 1109 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1110 | activate_locked: |
Rik van Riel | 68a22394 | 2008-10-18 20:26:23 -0700 | [diff] [blame] | 1111 | /* Not a candidate for swapping, so reclaim swap space. */ |
| 1112 | if (PageSwapCache(page) && vm_swap_full()) |
Hugh Dickins | a2c43ee | 2009-01-06 14:39:36 -0800 | [diff] [blame] | 1113 | try_to_free_swap(page); |
Sasha Levin | 309381fea | 2014-01-23 15:52:54 -0800 | [diff] [blame] | 1114 | VM_BUG_ON_PAGE(PageActive(page), page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1115 | SetPageActive(page); |
| 1116 | pgactivate++; |
| 1117 | keep_locked: |
| 1118 | unlock_page(page); |
| 1119 | keep: |
| 1120 | list_add(&page->lru, &ret_pages); |
Sasha Levin | 309381fea | 2014-01-23 15:52:54 -0800 | [diff] [blame] | 1121 | VM_BUG_ON_PAGE(PageLRU(page) || PageUnevictable(page), page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1122 | } |
Mel Gorman | abe4c3b | 2010-08-09 17:19:31 -0700 | [diff] [blame] | 1123 | |
Konstantin Khlebnikov | cc59850 | 2012-01-10 15:07:04 -0800 | [diff] [blame] | 1124 | free_hot_cold_page_list(&free_pages, 1); |
Mel Gorman | abe4c3b | 2010-08-09 17:19:31 -0700 | [diff] [blame] | 1125 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1126 | list_splice(&ret_pages, page_list); |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 1127 | count_vm_events(PGACTIVATE, pgactivate); |
Tim Chen | 69980e3 | 2012-07-31 16:46:08 -0700 | [diff] [blame] | 1128 | mem_cgroup_uncharge_end(); |
Mel Gorman | 8e95028 | 2013-07-03 15:02:02 -0700 | [diff] [blame] | 1129 | *ret_nr_dirty += nr_dirty; |
| 1130 | *ret_nr_congested += nr_congested; |
Mel Gorman | d43006d | 2013-07-03 15:01:50 -0700 | [diff] [blame] | 1131 | *ret_nr_unqueued_dirty += nr_unqueued_dirty; |
Mel Gorman | 92df3a7 | 2011-10-31 17:07:56 -0700 | [diff] [blame] | 1132 | *ret_nr_writeback += nr_writeback; |
Mel Gorman | b1a6f21 | 2013-07-03 15:01:58 -0700 | [diff] [blame] | 1133 | *ret_nr_immediate += nr_immediate; |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1134 | return nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1135 | } |
| 1136 | |
Minchan Kim | 02c6de8 | 2012-10-08 16:31:55 -0700 | [diff] [blame] | 1137 | unsigned long reclaim_clean_pages_from_list(struct zone *zone, |
| 1138 | struct list_head *page_list) |
| 1139 | { |
| 1140 | struct scan_control sc = { |
| 1141 | .gfp_mask = GFP_KERNEL, |
| 1142 | .priority = DEF_PRIORITY, |
| 1143 | .may_unmap = 1, |
| 1144 | }; |
Mel Gorman | 8e95028 | 2013-07-03 15:02:02 -0700 | [diff] [blame] | 1145 | unsigned long ret, dummy1, dummy2, dummy3, dummy4, dummy5; |
Minchan Kim | 02c6de8 | 2012-10-08 16:31:55 -0700 | [diff] [blame] | 1146 | struct page *page, *next; |
| 1147 | LIST_HEAD(clean_pages); |
| 1148 | |
| 1149 | list_for_each_entry_safe(page, next, page_list, lru) { |
Rafael Aquini | 117aad1 | 2013-09-30 13:45:16 -0700 | [diff] [blame] | 1150 | if (page_is_file_cache(page) && !PageDirty(page) && |
| 1151 | !isolated_balloon_page(page)) { |
Minchan Kim | 02c6de8 | 2012-10-08 16:31:55 -0700 | [diff] [blame] | 1152 | ClearPageActive(page); |
| 1153 | list_move(&page->lru, &clean_pages); |
| 1154 | } |
| 1155 | } |
| 1156 | |
| 1157 | ret = shrink_page_list(&clean_pages, zone, &sc, |
Mel Gorman | 8e95028 | 2013-07-03 15:02:02 -0700 | [diff] [blame] | 1158 | TTU_UNMAP|TTU_IGNORE_ACCESS, |
| 1159 | &dummy1, &dummy2, &dummy3, &dummy4, &dummy5, true); |
Minchan Kim | 02c6de8 | 2012-10-08 16:31:55 -0700 | [diff] [blame] | 1160 | list_splice(&clean_pages, page_list); |
Christoph Lameter | 83da751 | 2014-04-18 15:07:10 -0700 | [diff] [blame] | 1161 | mod_zone_page_state(zone, NR_ISOLATED_FILE, -ret); |
Minchan Kim | 02c6de8 | 2012-10-08 16:31:55 -0700 | [diff] [blame] | 1162 | return ret; |
| 1163 | } |
| 1164 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1165 | /* |
| 1166 | * Attempt to remove the specified page from its LRU. Only take this page |
| 1167 | * if it is of the appropriate PageActive status. Pages which are being |
| 1168 | * freed elsewhere are also ignored. |
| 1169 | * |
| 1170 | * page: page to consider |
| 1171 | * mode: one of the LRU isolation modes defined above |
| 1172 | * |
| 1173 | * returns 0 on success, -ve errno on failure. |
| 1174 | */ |
Konstantin Khlebnikov | f3fd4a6 | 2012-05-29 15:06:54 -0700 | [diff] [blame] | 1175 | int __isolate_lru_page(struct page *page, isolate_mode_t mode) |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1176 | { |
| 1177 | int ret = -EINVAL; |
| 1178 | |
| 1179 | /* Only take pages on the LRU. */ |
| 1180 | if (!PageLRU(page)) |
| 1181 | return ret; |
| 1182 | |
Minchan Kim | e46a287 | 2012-10-08 16:33:48 -0700 | [diff] [blame] | 1183 | /* Compaction should not handle unevictable pages but CMA can do so */ |
| 1184 | if (PageUnevictable(page) && !(mode & ISOLATE_UNEVICTABLE)) |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 1185 | return ret; |
| 1186 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1187 | ret = -EBUSY; |
KAMEZAWA Hiroyuki | 08e552c | 2009-01-07 18:08:01 -0800 | [diff] [blame] | 1188 | |
Mel Gorman | c824493 | 2012-01-12 17:19:38 -0800 | [diff] [blame] | 1189 | /* |
| 1190 | * To minimise LRU disruption, the caller can indicate that it only |
| 1191 | * wants to isolate pages it will be able to operate on without |
| 1192 | * blocking - clean pages for the most part. |
| 1193 | * |
| 1194 | * ISOLATE_CLEAN means that only clean pages should be isolated. This |
| 1195 | * is used by reclaim when it is cannot write to backing storage |
| 1196 | * |
| 1197 | * ISOLATE_ASYNC_MIGRATE is used to indicate that it only wants to pages |
| 1198 | * that it is possible to migrate without blocking |
| 1199 | */ |
| 1200 | if (mode & (ISOLATE_CLEAN|ISOLATE_ASYNC_MIGRATE)) { |
| 1201 | /* All the caller can do on PageWriteback is block */ |
| 1202 | if (PageWriteback(page)) |
| 1203 | return ret; |
| 1204 | |
| 1205 | if (PageDirty(page)) { |
| 1206 | struct address_space *mapping; |
| 1207 | |
| 1208 | /* ISOLATE_CLEAN means only clean pages */ |
| 1209 | if (mode & ISOLATE_CLEAN) |
| 1210 | return ret; |
| 1211 | |
| 1212 | /* |
| 1213 | * Only pages without mappings or that have a |
| 1214 | * ->migratepage callback are possible to migrate |
| 1215 | * without blocking |
| 1216 | */ |
| 1217 | mapping = page_mapping(page); |
| 1218 | if (mapping && !mapping->a_ops->migratepage) |
| 1219 | return ret; |
| 1220 | } |
| 1221 | } |
Minchan Kim | 39deaf8 | 2011-10-31 17:06:51 -0700 | [diff] [blame] | 1222 | |
Minchan Kim | f80c067 | 2011-10-31 17:06:55 -0700 | [diff] [blame] | 1223 | if ((mode & ISOLATE_UNMAPPED) && page_mapped(page)) |
| 1224 | return ret; |
| 1225 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1226 | if (likely(get_page_unless_zero(page))) { |
| 1227 | /* |
| 1228 | * Be careful not to clear PageLRU until after we're |
| 1229 | * sure the page is not being freed elsewhere -- the |
| 1230 | * page release code relies on it. |
| 1231 | */ |
| 1232 | ClearPageLRU(page); |
| 1233 | ret = 0; |
| 1234 | } |
| 1235 | |
| 1236 | return ret; |
| 1237 | } |
| 1238 | |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 1239 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1240 | * zone->lru_lock is heavily contended. Some of the functions that |
| 1241 | * shrink the lists perform better by taking out a batch of pages |
| 1242 | * and working on them outside the LRU lock. |
| 1243 | * |
| 1244 | * For pagecache intensive workloads, this function is the hottest |
| 1245 | * spot in the kernel (apart from copy_*_user functions). |
| 1246 | * |
| 1247 | * Appropriate locks must be held before calling this function. |
| 1248 | * |
| 1249 | * @nr_to_scan: The number of pages to look through on the list. |
Konstantin Khlebnikov | 5dc3597 | 2012-05-29 15:06:58 -0700 | [diff] [blame] | 1250 | * @lruvec: The LRU vector to pull pages from. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1251 | * @dst: The temp list to put pages on to. |
Hugh Dickins | f626012 | 2012-01-12 17:20:06 -0800 | [diff] [blame] | 1252 | * @nr_scanned: The number of pages that were scanned. |
Rik van Riel | fe2c2a1 | 2012-03-21 16:33:51 -0700 | [diff] [blame] | 1253 | * @sc: The scan_control struct for this reclaim session |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1254 | * @mode: One of the LRU isolation modes |
Konstantin Khlebnikov | 3cb9945 | 2012-05-29 15:06:53 -0700 | [diff] [blame] | 1255 | * @lru: LRU list id for isolating |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1256 | * |
| 1257 | * returns how many pages were moved onto *@dst. |
| 1258 | */ |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1259 | static unsigned long isolate_lru_pages(unsigned long nr_to_scan, |
Konstantin Khlebnikov | 5dc3597 | 2012-05-29 15:06:58 -0700 | [diff] [blame] | 1260 | struct lruvec *lruvec, struct list_head *dst, |
Rik van Riel | fe2c2a1 | 2012-03-21 16:33:51 -0700 | [diff] [blame] | 1261 | unsigned long *nr_scanned, struct scan_control *sc, |
Konstantin Khlebnikov | 3cb9945 | 2012-05-29 15:06:53 -0700 | [diff] [blame] | 1262 | isolate_mode_t mode, enum lru_list lru) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1263 | { |
Hugh Dickins | 75b00af | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1264 | struct list_head *src = &lruvec->lists[lru]; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1265 | unsigned long nr_taken = 0; |
Wu Fengguang | c9b02d9 | 2006-03-22 00:08:23 -0800 | [diff] [blame] | 1266 | unsigned long scan; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1267 | |
Wu Fengguang | c9b02d9 | 2006-03-22 00:08:23 -0800 | [diff] [blame] | 1268 | for (scan = 0; scan < nr_to_scan && !list_empty(src); scan++) { |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1269 | struct page *page; |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1270 | int nr_pages; |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1271 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1272 | page = lru_to_page(src); |
| 1273 | prefetchw_prev_lru_page(page, src, flags); |
| 1274 | |
Sasha Levin | 309381fea | 2014-01-23 15:52:54 -0800 | [diff] [blame] | 1275 | VM_BUG_ON_PAGE(!PageLRU(page), page); |
Nick Piggin | 8d438f9 | 2006-03-22 00:07:59 -0800 | [diff] [blame] | 1276 | |
Konstantin Khlebnikov | f3fd4a6 | 2012-05-29 15:06:54 -0700 | [diff] [blame] | 1277 | switch (__isolate_lru_page(page, mode)) { |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1278 | case 0: |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1279 | nr_pages = hpage_nr_pages(page); |
| 1280 | mem_cgroup_update_lru_size(lruvec, lru, -nr_pages); |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1281 | list_move(&page->lru, dst); |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1282 | nr_taken += nr_pages; |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1283 | break; |
Nick Piggin | 46453a6 | 2006-03-22 00:07:58 -0800 | [diff] [blame] | 1284 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1285 | case -EBUSY: |
| 1286 | /* else it is being freed elsewhere */ |
| 1287 | list_move(&page->lru, src); |
| 1288 | continue; |
| 1289 | |
| 1290 | default: |
| 1291 | BUG(); |
| 1292 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1293 | } |
| 1294 | |
Hugh Dickins | f626012 | 2012-01-12 17:20:06 -0800 | [diff] [blame] | 1295 | *nr_scanned = scan; |
Hugh Dickins | 75b00af | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1296 | trace_mm_vmscan_lru_isolate(sc->order, nr_to_scan, scan, |
| 1297 | nr_taken, mode, is_file_lru(lru)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1298 | return nr_taken; |
| 1299 | } |
| 1300 | |
Nick Piggin | 62695a8 | 2008-10-18 20:26:09 -0700 | [diff] [blame] | 1301 | /** |
| 1302 | * isolate_lru_page - tries to isolate a page from its LRU list |
| 1303 | * @page: page to isolate from its LRU list |
| 1304 | * |
| 1305 | * Isolates a @page from an LRU list, clears PageLRU and adjusts the |
| 1306 | * vmstat statistic corresponding to whatever LRU list the page was on. |
| 1307 | * |
| 1308 | * Returns 0 if the page was removed from an LRU list. |
| 1309 | * Returns -EBUSY if the page was not on an LRU list. |
| 1310 | * |
| 1311 | * The returned page will have PageLRU() cleared. If it was found on |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 1312 | * the active list, it will have PageActive set. If it was found on |
| 1313 | * the unevictable list, it will have the PageUnevictable bit set. That flag |
| 1314 | * may need to be cleared by the caller before letting the page go. |
Nick Piggin | 62695a8 | 2008-10-18 20:26:09 -0700 | [diff] [blame] | 1315 | * |
| 1316 | * The vmstat statistic corresponding to the list on which the page was |
| 1317 | * found will be decremented. |
| 1318 | * |
| 1319 | * Restrictions: |
| 1320 | * (1) Must be called with an elevated refcount on the page. This is a |
| 1321 | * fundamentnal difference from isolate_lru_pages (which is called |
| 1322 | * without a stable reference). |
| 1323 | * (2) the lru_lock must not be held. |
| 1324 | * (3) interrupts must be enabled. |
| 1325 | */ |
| 1326 | int isolate_lru_page(struct page *page) |
| 1327 | { |
| 1328 | int ret = -EBUSY; |
| 1329 | |
Sasha Levin | 309381fea | 2014-01-23 15:52:54 -0800 | [diff] [blame] | 1330 | VM_BUG_ON_PAGE(!page_count(page), page); |
Konstantin Khlebnikov | 0c91731 | 2011-05-24 17:12:21 -0700 | [diff] [blame] | 1331 | |
Nick Piggin | 62695a8 | 2008-10-18 20:26:09 -0700 | [diff] [blame] | 1332 | if (PageLRU(page)) { |
| 1333 | struct zone *zone = page_zone(page); |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1334 | struct lruvec *lruvec; |
Nick Piggin | 62695a8 | 2008-10-18 20:26:09 -0700 | [diff] [blame] | 1335 | |
| 1336 | spin_lock_irq(&zone->lru_lock); |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1337 | lruvec = mem_cgroup_page_lruvec(page, zone); |
Konstantin Khlebnikov | 0c91731 | 2011-05-24 17:12:21 -0700 | [diff] [blame] | 1338 | if (PageLRU(page)) { |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 1339 | int lru = page_lru(page); |
Konstantin Khlebnikov | 0c91731 | 2011-05-24 17:12:21 -0700 | [diff] [blame] | 1340 | get_page(page); |
Nick Piggin | 62695a8 | 2008-10-18 20:26:09 -0700 | [diff] [blame] | 1341 | ClearPageLRU(page); |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1342 | del_page_from_lru_list(page, lruvec, lru); |
| 1343 | ret = 0; |
Nick Piggin | 62695a8 | 2008-10-18 20:26:09 -0700 | [diff] [blame] | 1344 | } |
| 1345 | spin_unlock_irq(&zone->lru_lock); |
| 1346 | } |
| 1347 | return ret; |
| 1348 | } |
| 1349 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1350 | /* |
Fengguang Wu | d37dd5d | 2012-12-18 14:23:28 -0800 | [diff] [blame] | 1351 | * A direct reclaimer may isolate SWAP_CLUSTER_MAX pages from the LRU list and |
| 1352 | * then get resheduled. When there are massive number of tasks doing page |
| 1353 | * allocation, such sleeping direct reclaimers may keep piling up on each CPU, |
| 1354 | * the LRU list will go small and be scanned faster than necessary, leading to |
| 1355 | * unnecessary swapping, thrashing and OOM. |
Rik van Riel | 35cd781 | 2009-09-21 17:01:38 -0700 | [diff] [blame] | 1356 | */ |
| 1357 | static int too_many_isolated(struct zone *zone, int file, |
| 1358 | struct scan_control *sc) |
| 1359 | { |
| 1360 | unsigned long inactive, isolated; |
| 1361 | |
| 1362 | if (current_is_kswapd()) |
| 1363 | return 0; |
| 1364 | |
Johannes Weiner | 89b5fae | 2012-01-12 17:17:50 -0800 | [diff] [blame] | 1365 | if (!global_reclaim(sc)) |
Rik van Riel | 35cd781 | 2009-09-21 17:01:38 -0700 | [diff] [blame] | 1366 | return 0; |
| 1367 | |
| 1368 | if (file) { |
| 1369 | inactive = zone_page_state(zone, NR_INACTIVE_FILE); |
| 1370 | isolated = zone_page_state(zone, NR_ISOLATED_FILE); |
| 1371 | } else { |
| 1372 | inactive = zone_page_state(zone, NR_INACTIVE_ANON); |
| 1373 | isolated = zone_page_state(zone, NR_ISOLATED_ANON); |
| 1374 | } |
| 1375 | |
Fengguang Wu | 3cf2384 | 2012-12-18 14:23:31 -0800 | [diff] [blame] | 1376 | /* |
| 1377 | * GFP_NOIO/GFP_NOFS callers are allowed to isolate more pages, so they |
| 1378 | * won't get blocked by normal direct-reclaimers, forming a circular |
| 1379 | * deadlock. |
| 1380 | */ |
| 1381 | if ((sc->gfp_mask & GFP_IOFS) == GFP_IOFS) |
| 1382 | inactive >>= 3; |
| 1383 | |
Rik van Riel | 35cd781 | 2009-09-21 17:01:38 -0700 | [diff] [blame] | 1384 | return isolated > inactive; |
| 1385 | } |
| 1386 | |
Mel Gorman | 6663562 | 2010-08-09 17:19:30 -0700 | [diff] [blame] | 1387 | static noinline_for_stack void |
Hugh Dickins | 75b00af | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1388 | putback_inactive_pages(struct lruvec *lruvec, struct list_head *page_list) |
Mel Gorman | 6663562 | 2010-08-09 17:19:30 -0700 | [diff] [blame] | 1389 | { |
Konstantin Khlebnikov | 27ac81d | 2012-05-29 15:07:00 -0700 | [diff] [blame] | 1390 | struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat; |
| 1391 | struct zone *zone = lruvec_zone(lruvec); |
Hugh Dickins | 3f79768 | 2012-01-12 17:20:07 -0800 | [diff] [blame] | 1392 | LIST_HEAD(pages_to_free); |
Mel Gorman | 6663562 | 2010-08-09 17:19:30 -0700 | [diff] [blame] | 1393 | |
Mel Gorman | 6663562 | 2010-08-09 17:19:30 -0700 | [diff] [blame] | 1394 | /* |
| 1395 | * Put back any unfreeable pages. |
| 1396 | */ |
Mel Gorman | 6663562 | 2010-08-09 17:19:30 -0700 | [diff] [blame] | 1397 | while (!list_empty(page_list)) { |
Hugh Dickins | 3f79768 | 2012-01-12 17:20:07 -0800 | [diff] [blame] | 1398 | struct page *page = lru_to_page(page_list); |
Mel Gorman | 6663562 | 2010-08-09 17:19:30 -0700 | [diff] [blame] | 1399 | int lru; |
Hugh Dickins | 3f79768 | 2012-01-12 17:20:07 -0800 | [diff] [blame] | 1400 | |
Sasha Levin | 309381fea | 2014-01-23 15:52:54 -0800 | [diff] [blame] | 1401 | VM_BUG_ON_PAGE(PageLRU(page), page); |
Mel Gorman | 6663562 | 2010-08-09 17:19:30 -0700 | [diff] [blame] | 1402 | list_del(&page->lru); |
Hugh Dickins | 39b5f29 | 2012-10-08 16:33:18 -0700 | [diff] [blame] | 1403 | if (unlikely(!page_evictable(page))) { |
Mel Gorman | 6663562 | 2010-08-09 17:19:30 -0700 | [diff] [blame] | 1404 | spin_unlock_irq(&zone->lru_lock); |
| 1405 | putback_lru_page(page); |
| 1406 | spin_lock_irq(&zone->lru_lock); |
| 1407 | continue; |
| 1408 | } |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1409 | |
| 1410 | lruvec = mem_cgroup_page_lruvec(page, zone); |
| 1411 | |
Linus Torvalds | 7a60857 | 2011-01-17 14:42:19 -0800 | [diff] [blame] | 1412 | SetPageLRU(page); |
Mel Gorman | 6663562 | 2010-08-09 17:19:30 -0700 | [diff] [blame] | 1413 | lru = page_lru(page); |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1414 | add_page_to_lru_list(page, lruvec, lru); |
| 1415 | |
Mel Gorman | 6663562 | 2010-08-09 17:19:30 -0700 | [diff] [blame] | 1416 | if (is_active_lru(lru)) { |
| 1417 | int file = is_file_lru(lru); |
Rik van Riel | 9992af1 | 2011-01-13 15:47:13 -0800 | [diff] [blame] | 1418 | int numpages = hpage_nr_pages(page); |
| 1419 | reclaim_stat->recent_rotated[file] += numpages; |
Mel Gorman | 6663562 | 2010-08-09 17:19:30 -0700 | [diff] [blame] | 1420 | } |
Hugh Dickins | 2bcf887 | 2012-01-12 17:19:56 -0800 | [diff] [blame] | 1421 | if (put_page_testzero(page)) { |
| 1422 | __ClearPageLRU(page); |
| 1423 | __ClearPageActive(page); |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1424 | del_page_from_lru_list(page, lruvec, lru); |
Hugh Dickins | 2bcf887 | 2012-01-12 17:19:56 -0800 | [diff] [blame] | 1425 | |
| 1426 | if (unlikely(PageCompound(page))) { |
| 1427 | spin_unlock_irq(&zone->lru_lock); |
| 1428 | (*get_compound_page_dtor(page))(page); |
| 1429 | spin_lock_irq(&zone->lru_lock); |
| 1430 | } else |
| 1431 | list_add(&page->lru, &pages_to_free); |
Mel Gorman | 6663562 | 2010-08-09 17:19:30 -0700 | [diff] [blame] | 1432 | } |
| 1433 | } |
Mel Gorman | 6663562 | 2010-08-09 17:19:30 -0700 | [diff] [blame] | 1434 | |
Hugh Dickins | 3f79768 | 2012-01-12 17:20:07 -0800 | [diff] [blame] | 1435 | /* |
| 1436 | * To save our caller's stack, now use input list for pages to free. |
| 1437 | */ |
| 1438 | list_splice(&pages_to_free, page_list); |
Mel Gorman | 6663562 | 2010-08-09 17:19:30 -0700 | [diff] [blame] | 1439 | } |
| 1440 | |
| 1441 | /* |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 1442 | * shrink_inactive_list() is a helper for shrink_zone(). It returns the number |
| 1443 | * of reclaimed pages |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1444 | */ |
Mel Gorman | 6663562 | 2010-08-09 17:19:30 -0700 | [diff] [blame] | 1445 | static noinline_for_stack unsigned long |
Konstantin Khlebnikov | 1a93be0 | 2012-05-29 15:07:01 -0700 | [diff] [blame] | 1446 | shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, |
Konstantin Khlebnikov | 9e3b2f8 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 1447 | struct scan_control *sc, enum lru_list lru) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1448 | { |
| 1449 | LIST_HEAD(page_list); |
KOSAKI Motohiro | e247dbc | 2010-08-09 17:19:28 -0700 | [diff] [blame] | 1450 | unsigned long nr_scanned; |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1451 | unsigned long nr_reclaimed = 0; |
KOSAKI Motohiro | e247dbc | 2010-08-09 17:19:28 -0700 | [diff] [blame] | 1452 | unsigned long nr_taken; |
Mel Gorman | 8e95028 | 2013-07-03 15:02:02 -0700 | [diff] [blame] | 1453 | unsigned long nr_dirty = 0; |
| 1454 | unsigned long nr_congested = 0; |
Mel Gorman | e2be15f | 2013-07-03 15:01:57 -0700 | [diff] [blame] | 1455 | unsigned long nr_unqueued_dirty = 0; |
Mel Gorman | 92df3a7 | 2011-10-31 17:07:56 -0700 | [diff] [blame] | 1456 | unsigned long nr_writeback = 0; |
Mel Gorman | b1a6f21 | 2013-07-03 15:01:58 -0700 | [diff] [blame] | 1457 | unsigned long nr_immediate = 0; |
Konstantin Khlebnikov | f3fd4a6 | 2012-05-29 15:06:54 -0700 | [diff] [blame] | 1458 | isolate_mode_t isolate_mode = 0; |
Konstantin Khlebnikov | 3cb9945 | 2012-05-29 15:06:53 -0700 | [diff] [blame] | 1459 | int file = is_file_lru(lru); |
Konstantin Khlebnikov | 1a93be0 | 2012-05-29 15:07:01 -0700 | [diff] [blame] | 1460 | struct zone *zone = lruvec_zone(lruvec); |
| 1461 | struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat; |
KOSAKI Motohiro | 78dc583 | 2009-06-16 15:31:40 -0700 | [diff] [blame] | 1462 | |
Rik van Riel | 35cd781 | 2009-09-21 17:01:38 -0700 | [diff] [blame] | 1463 | while (unlikely(too_many_isolated(zone, file, sc))) { |
KOSAKI Motohiro | 58355c7 | 2009-10-26 16:49:35 -0700 | [diff] [blame] | 1464 | congestion_wait(BLK_RW_ASYNC, HZ/10); |
Rik van Riel | 35cd781 | 2009-09-21 17:01:38 -0700 | [diff] [blame] | 1465 | |
| 1466 | /* We are about to die and free our memory. Return now. */ |
| 1467 | if (fatal_signal_pending(current)) |
| 1468 | return SWAP_CLUSTER_MAX; |
| 1469 | } |
| 1470 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1471 | lru_add_drain(); |
Minchan Kim | f80c067 | 2011-10-31 17:06:55 -0700 | [diff] [blame] | 1472 | |
| 1473 | if (!sc->may_unmap) |
Hillf Danton | 6131728 | 2012-03-21 16:33:48 -0700 | [diff] [blame] | 1474 | isolate_mode |= ISOLATE_UNMAPPED; |
Minchan Kim | f80c067 | 2011-10-31 17:06:55 -0700 | [diff] [blame] | 1475 | if (!sc->may_writepage) |
Hillf Danton | 6131728 | 2012-03-21 16:33:48 -0700 | [diff] [blame] | 1476 | isolate_mode |= ISOLATE_CLEAN; |
Minchan Kim | f80c067 | 2011-10-31 17:06:55 -0700 | [diff] [blame] | 1477 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1478 | spin_lock_irq(&zone->lru_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1479 | |
Konstantin Khlebnikov | 5dc3597 | 2012-05-29 15:06:58 -0700 | [diff] [blame] | 1480 | nr_taken = isolate_lru_pages(nr_to_scan, lruvec, &page_list, |
| 1481 | &nr_scanned, sc, isolate_mode, lru); |
Konstantin Khlebnikov | 95d918f | 2012-05-29 15:06:59 -0700 | [diff] [blame] | 1482 | |
| 1483 | __mod_zone_page_state(zone, NR_LRU_BASE + lru, -nr_taken); |
| 1484 | __mod_zone_page_state(zone, NR_ISOLATED_ANON + file, nr_taken); |
| 1485 | |
Johannes Weiner | 89b5fae | 2012-01-12 17:17:50 -0800 | [diff] [blame] | 1486 | if (global_reclaim(sc)) { |
KOSAKI Motohiro | e247dbc | 2010-08-09 17:19:28 -0700 | [diff] [blame] | 1487 | zone->pages_scanned += nr_scanned; |
KOSAKI Motohiro | b35ea17 | 2009-09-21 17:01:36 -0700 | [diff] [blame] | 1488 | if (current_is_kswapd()) |
Hugh Dickins | 75b00af | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1489 | __count_zone_vm_events(PGSCAN_KSWAPD, zone, nr_scanned); |
KOSAKI Motohiro | e247dbc | 2010-08-09 17:19:28 -0700 | [diff] [blame] | 1490 | else |
Hugh Dickins | 75b00af | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1491 | __count_zone_vm_events(PGSCAN_DIRECT, zone, nr_scanned); |
KOSAKI Motohiro | e247dbc | 2010-08-09 17:19:28 -0700 | [diff] [blame] | 1492 | } |
Hillf Danton | d563c05 | 2012-03-21 16:34:02 -0700 | [diff] [blame] | 1493 | spin_unlock_irq(&zone->lru_lock); |
KOSAKI Motohiro | a731286 | 2009-09-21 17:01:37 -0700 | [diff] [blame] | 1494 | |
Hillf Danton | d563c05 | 2012-03-21 16:34:02 -0700 | [diff] [blame] | 1495 | if (nr_taken == 0) |
Mel Gorman | 6663562 | 2010-08-09 17:19:30 -0700 | [diff] [blame] | 1496 | return 0; |
KOSAKI Motohiro | e247dbc | 2010-08-09 17:19:28 -0700 | [diff] [blame] | 1497 | |
Minchan Kim | 02c6de8 | 2012-10-08 16:31:55 -0700 | [diff] [blame] | 1498 | nr_reclaimed = shrink_page_list(&page_list, zone, sc, TTU_UNMAP, |
Mel Gorman | 8e95028 | 2013-07-03 15:02:02 -0700 | [diff] [blame] | 1499 | &nr_dirty, &nr_unqueued_dirty, &nr_congested, |
| 1500 | &nr_writeback, &nr_immediate, |
| 1501 | false); |
KOSAKI Motohiro | e247dbc | 2010-08-09 17:19:28 -0700 | [diff] [blame] | 1502 | |
Hugh Dickins | 3f79768 | 2012-01-12 17:20:07 -0800 | [diff] [blame] | 1503 | spin_lock_irq(&zone->lru_lock); |
| 1504 | |
Konstantin Khlebnikov | 95d918f | 2012-05-29 15:06:59 -0700 | [diff] [blame] | 1505 | reclaim_stat->recent_scanned[file] += nr_taken; |
Hillf Danton | d563c05 | 2012-03-21 16:34:02 -0700 | [diff] [blame] | 1506 | |
Ying Han | 904249a | 2012-04-25 16:01:48 -0700 | [diff] [blame] | 1507 | if (global_reclaim(sc)) { |
| 1508 | if (current_is_kswapd()) |
| 1509 | __count_zone_vm_events(PGSTEAL_KSWAPD, zone, |
| 1510 | nr_reclaimed); |
| 1511 | else |
| 1512 | __count_zone_vm_events(PGSTEAL_DIRECT, zone, |
| 1513 | nr_reclaimed); |
| 1514 | } |
KOSAKI Motohiro | e247dbc | 2010-08-09 17:19:28 -0700 | [diff] [blame] | 1515 | |
Konstantin Khlebnikov | 27ac81d | 2012-05-29 15:07:00 -0700 | [diff] [blame] | 1516 | putback_inactive_pages(lruvec, &page_list); |
Hugh Dickins | 3f79768 | 2012-01-12 17:20:07 -0800 | [diff] [blame] | 1517 | |
Konstantin Khlebnikov | 95d918f | 2012-05-29 15:06:59 -0700 | [diff] [blame] | 1518 | __mod_zone_page_state(zone, NR_ISOLATED_ANON + file, -nr_taken); |
Hugh Dickins | 3f79768 | 2012-01-12 17:20:07 -0800 | [diff] [blame] | 1519 | |
| 1520 | spin_unlock_irq(&zone->lru_lock); |
| 1521 | |
| 1522 | free_hot_cold_page_list(&page_list, 1); |
Mel Gorman | e11da5b | 2010-10-26 14:21:40 -0700 | [diff] [blame] | 1523 | |
Mel Gorman | 92df3a7 | 2011-10-31 17:07:56 -0700 | [diff] [blame] | 1524 | /* |
| 1525 | * If reclaim is isolating dirty pages under writeback, it implies |
| 1526 | * that the long-lived page allocation rate is exceeding the page |
| 1527 | * laundering rate. Either the global limits are not being effective |
| 1528 | * at throttling processes due to the page distribution throughout |
| 1529 | * zones or there is heavy usage of a slow backing device. The |
| 1530 | * only option is to throttle from reclaim context which is not ideal |
| 1531 | * as there is no guarantee the dirtying process is throttled in the |
| 1532 | * same way balance_dirty_pages() manages. |
| 1533 | * |
Mel Gorman | 8e95028 | 2013-07-03 15:02:02 -0700 | [diff] [blame] | 1534 | * Once a zone is flagged ZONE_WRITEBACK, kswapd will count the number |
| 1535 | * of pages under pages flagged for immediate reclaim and stall if any |
| 1536 | * are encountered in the nr_immediate check below. |
Mel Gorman | 92df3a7 | 2011-10-31 17:07:56 -0700 | [diff] [blame] | 1537 | */ |
Mel Gorman | 918fc71 | 2013-07-08 16:00:25 -0700 | [diff] [blame] | 1538 | if (nr_writeback && nr_writeback == nr_taken) |
Mel Gorman | 283aba9 | 2013-07-03 15:01:51 -0700 | [diff] [blame] | 1539 | zone_set_flag(zone, ZONE_WRITEBACK); |
Mel Gorman | 92df3a7 | 2011-10-31 17:07:56 -0700 | [diff] [blame] | 1540 | |
Mel Gorman | d43006d | 2013-07-03 15:01:50 -0700 | [diff] [blame] | 1541 | /* |
Mel Gorman | b1a6f21 | 2013-07-03 15:01:58 -0700 | [diff] [blame] | 1542 | * memcg will stall in page writeback so only consider forcibly |
| 1543 | * stalling for global reclaim |
Mel Gorman | d43006d | 2013-07-03 15:01:50 -0700 | [diff] [blame] | 1544 | */ |
Mel Gorman | b1a6f21 | 2013-07-03 15:01:58 -0700 | [diff] [blame] | 1545 | if (global_reclaim(sc)) { |
| 1546 | /* |
Mel Gorman | 8e95028 | 2013-07-03 15:02:02 -0700 | [diff] [blame] | 1547 | * Tag a zone as congested if all the dirty pages scanned were |
| 1548 | * backed by a congested BDI and wait_iff_congested will stall. |
| 1549 | */ |
| 1550 | if (nr_dirty && nr_dirty == nr_congested) |
| 1551 | zone_set_flag(zone, ZONE_CONGESTED); |
| 1552 | |
| 1553 | /* |
Mel Gorman | b1a6f21 | 2013-07-03 15:01:58 -0700 | [diff] [blame] | 1554 | * If dirty pages are scanned that are not queued for IO, it |
| 1555 | * implies that flushers are not keeping up. In this case, flag |
| 1556 | * the zone ZONE_TAIL_LRU_DIRTY and kswapd will start writing |
| 1557 | * pages from reclaim context. It will forcibly stall in the |
| 1558 | * next check. |
| 1559 | */ |
| 1560 | if (nr_unqueued_dirty == nr_taken) |
| 1561 | zone_set_flag(zone, ZONE_TAIL_LRU_DIRTY); |
| 1562 | |
| 1563 | /* |
| 1564 | * In addition, if kswapd scans pages marked marked for |
| 1565 | * immediate reclaim and under writeback (nr_immediate), it |
| 1566 | * implies that pages are cycling through the LRU faster than |
| 1567 | * they are written so also forcibly stall. |
| 1568 | */ |
| 1569 | if (nr_unqueued_dirty == nr_taken || nr_immediate) |
| 1570 | congestion_wait(BLK_RW_ASYNC, HZ/10); |
Mel Gorman | e2be15f | 2013-07-03 15:01:57 -0700 | [diff] [blame] | 1571 | } |
Mel Gorman | d43006d | 2013-07-03 15:01:50 -0700 | [diff] [blame] | 1572 | |
Mel Gorman | 8e95028 | 2013-07-03 15:02:02 -0700 | [diff] [blame] | 1573 | /* |
| 1574 | * Stall direct reclaim for IO completions if underlying BDIs or zone |
| 1575 | * is congested. Allow kswapd to continue until it starts encountering |
| 1576 | * unqueued dirty pages or cycling through the LRU too quickly. |
| 1577 | */ |
| 1578 | if (!sc->hibernation_mode && !current_is_kswapd()) |
| 1579 | wait_iff_congested(zone, BLK_RW_ASYNC, HZ/10); |
| 1580 | |
Mel Gorman | e11da5b | 2010-10-26 14:21:40 -0700 | [diff] [blame] | 1581 | trace_mm_vmscan_lru_shrink_inactive(zone->zone_pgdat->node_id, |
| 1582 | zone_idx(zone), |
| 1583 | nr_scanned, nr_reclaimed, |
Konstantin Khlebnikov | 9e3b2f8 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 1584 | sc->priority, |
Mel Gorman | 23b9da5 | 2012-05-29 15:06:20 -0700 | [diff] [blame] | 1585 | trace_shrink_flags(file)); |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1586 | return nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1587 | } |
| 1588 | |
Martin Bligh | 3bb1a852 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1589 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1590 | * This moves pages from the active list to the inactive list. |
| 1591 | * |
| 1592 | * We move them the other way if the page is referenced by one or more |
| 1593 | * processes, from rmap. |
| 1594 | * |
| 1595 | * If the pages are mostly unmapped, the processing is fast and it is |
| 1596 | * appropriate to hold zone->lru_lock across the whole operation. But if |
| 1597 | * the pages are mapped, the processing is slow (page_referenced()) so we |
| 1598 | * should drop zone->lru_lock around each page. It's impossible to balance |
| 1599 | * this, so instead we remove the pages from the LRU while processing them. |
| 1600 | * It is safe to rely on PG_active against the non-LRU pages in here because |
| 1601 | * nobody will play with that bit on a non-LRU page. |
| 1602 | * |
| 1603 | * The downside is that we have to touch page->_count against each page. |
| 1604 | * But we had to alter page->flags anyway. |
| 1605 | */ |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1606 | |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1607 | static void move_active_pages_to_lru(struct lruvec *lruvec, |
Wu Fengguang | 3eb4140 | 2009-06-16 15:33:13 -0700 | [diff] [blame] | 1608 | struct list_head *list, |
Hugh Dickins | 2bcf887 | 2012-01-12 17:19:56 -0800 | [diff] [blame] | 1609 | struct list_head *pages_to_free, |
Wu Fengguang | 3eb4140 | 2009-06-16 15:33:13 -0700 | [diff] [blame] | 1610 | enum lru_list lru) |
| 1611 | { |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1612 | struct zone *zone = lruvec_zone(lruvec); |
Wu Fengguang | 3eb4140 | 2009-06-16 15:33:13 -0700 | [diff] [blame] | 1613 | unsigned long pgmoved = 0; |
Wu Fengguang | 3eb4140 | 2009-06-16 15:33:13 -0700 | [diff] [blame] | 1614 | struct page *page; |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1615 | int nr_pages; |
Wu Fengguang | 3eb4140 | 2009-06-16 15:33:13 -0700 | [diff] [blame] | 1616 | |
Wu Fengguang | 3eb4140 | 2009-06-16 15:33:13 -0700 | [diff] [blame] | 1617 | while (!list_empty(list)) { |
| 1618 | page = lru_to_page(list); |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1619 | lruvec = mem_cgroup_page_lruvec(page, zone); |
Wu Fengguang | 3eb4140 | 2009-06-16 15:33:13 -0700 | [diff] [blame] | 1620 | |
Sasha Levin | 309381fea | 2014-01-23 15:52:54 -0800 | [diff] [blame] | 1621 | VM_BUG_ON_PAGE(PageLRU(page), page); |
Wu Fengguang | 3eb4140 | 2009-06-16 15:33:13 -0700 | [diff] [blame] | 1622 | SetPageLRU(page); |
| 1623 | |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1624 | nr_pages = hpage_nr_pages(page); |
| 1625 | mem_cgroup_update_lru_size(lruvec, lru, nr_pages); |
Johannes Weiner | 925b767 | 2012-01-12 17:18:15 -0800 | [diff] [blame] | 1626 | list_move(&page->lru, &lruvec->lists[lru]); |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1627 | pgmoved += nr_pages; |
Wu Fengguang | 3eb4140 | 2009-06-16 15:33:13 -0700 | [diff] [blame] | 1628 | |
Hugh Dickins | 2bcf887 | 2012-01-12 17:19:56 -0800 | [diff] [blame] | 1629 | if (put_page_testzero(page)) { |
| 1630 | __ClearPageLRU(page); |
| 1631 | __ClearPageActive(page); |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1632 | del_page_from_lru_list(page, lruvec, lru); |
Hugh Dickins | 2bcf887 | 2012-01-12 17:19:56 -0800 | [diff] [blame] | 1633 | |
| 1634 | if (unlikely(PageCompound(page))) { |
| 1635 | spin_unlock_irq(&zone->lru_lock); |
| 1636 | (*get_compound_page_dtor(page))(page); |
| 1637 | spin_lock_irq(&zone->lru_lock); |
| 1638 | } else |
| 1639 | list_add(&page->lru, pages_to_free); |
Wu Fengguang | 3eb4140 | 2009-06-16 15:33:13 -0700 | [diff] [blame] | 1640 | } |
| 1641 | } |
| 1642 | __mod_zone_page_state(zone, NR_LRU_BASE + lru, pgmoved); |
| 1643 | if (!is_active_lru(lru)) |
| 1644 | __count_vm_events(PGDEACTIVATE, pgmoved); |
| 1645 | } |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1646 | |
Hugh Dickins | f626012 | 2012-01-12 17:20:06 -0800 | [diff] [blame] | 1647 | static void shrink_active_list(unsigned long nr_to_scan, |
Konstantin Khlebnikov | 1a93be0 | 2012-05-29 15:07:01 -0700 | [diff] [blame] | 1648 | struct lruvec *lruvec, |
Johannes Weiner | f16015f | 2012-01-12 17:17:52 -0800 | [diff] [blame] | 1649 | struct scan_control *sc, |
Konstantin Khlebnikov | 9e3b2f8 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 1650 | enum lru_list lru) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1651 | { |
KOSAKI Motohiro | 44c241f | 2009-09-21 17:01:35 -0700 | [diff] [blame] | 1652 | unsigned long nr_taken; |
Hugh Dickins | f626012 | 2012-01-12 17:20:06 -0800 | [diff] [blame] | 1653 | unsigned long nr_scanned; |
Wu Fengguang | 6fe6b7e | 2009-06-16 15:33:05 -0700 | [diff] [blame] | 1654 | unsigned long vm_flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1655 | LIST_HEAD(l_hold); /* The pages which were snipped off */ |
Wu Fengguang | 8cab475 | 2009-06-16 15:33:12 -0700 | [diff] [blame] | 1656 | LIST_HEAD(l_active); |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1657 | LIST_HEAD(l_inactive); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1658 | struct page *page; |
Konstantin Khlebnikov | 1a93be0 | 2012-05-29 15:07:01 -0700 | [diff] [blame] | 1659 | struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat; |
KOSAKI Motohiro | 44c241f | 2009-09-21 17:01:35 -0700 | [diff] [blame] | 1660 | unsigned long nr_rotated = 0; |
Konstantin Khlebnikov | f3fd4a6 | 2012-05-29 15:06:54 -0700 | [diff] [blame] | 1661 | isolate_mode_t isolate_mode = 0; |
Konstantin Khlebnikov | 3cb9945 | 2012-05-29 15:06:53 -0700 | [diff] [blame] | 1662 | int file = is_file_lru(lru); |
Konstantin Khlebnikov | 1a93be0 | 2012-05-29 15:07:01 -0700 | [diff] [blame] | 1663 | struct zone *zone = lruvec_zone(lruvec); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1664 | |
| 1665 | lru_add_drain(); |
Minchan Kim | f80c067 | 2011-10-31 17:06:55 -0700 | [diff] [blame] | 1666 | |
| 1667 | if (!sc->may_unmap) |
Hillf Danton | 6131728 | 2012-03-21 16:33:48 -0700 | [diff] [blame] | 1668 | isolate_mode |= ISOLATE_UNMAPPED; |
Minchan Kim | f80c067 | 2011-10-31 17:06:55 -0700 | [diff] [blame] | 1669 | if (!sc->may_writepage) |
Hillf Danton | 6131728 | 2012-03-21 16:33:48 -0700 | [diff] [blame] | 1670 | isolate_mode |= ISOLATE_CLEAN; |
Minchan Kim | f80c067 | 2011-10-31 17:06:55 -0700 | [diff] [blame] | 1671 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1672 | spin_lock_irq(&zone->lru_lock); |
Johannes Weiner | 925b767 | 2012-01-12 17:18:15 -0800 | [diff] [blame] | 1673 | |
Konstantin Khlebnikov | 5dc3597 | 2012-05-29 15:06:58 -0700 | [diff] [blame] | 1674 | nr_taken = isolate_lru_pages(nr_to_scan, lruvec, &l_hold, |
| 1675 | &nr_scanned, sc, isolate_mode, lru); |
Johannes Weiner | 89b5fae | 2012-01-12 17:17:50 -0800 | [diff] [blame] | 1676 | if (global_reclaim(sc)) |
Hugh Dickins | f626012 | 2012-01-12 17:20:06 -0800 | [diff] [blame] | 1677 | zone->pages_scanned += nr_scanned; |
Johannes Weiner | 89b5fae | 2012-01-12 17:17:50 -0800 | [diff] [blame] | 1678 | |
Johannes Weiner | b7c46d1 | 2009-09-21 17:02:56 -0700 | [diff] [blame] | 1679 | reclaim_stat->recent_scanned[file] += nr_taken; |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1680 | |
Hugh Dickins | f626012 | 2012-01-12 17:20:06 -0800 | [diff] [blame] | 1681 | __count_zone_vm_events(PGREFILL, zone, nr_scanned); |
Konstantin Khlebnikov | 3cb9945 | 2012-05-29 15:06:53 -0700 | [diff] [blame] | 1682 | __mod_zone_page_state(zone, NR_LRU_BASE + lru, -nr_taken); |
KOSAKI Motohiro | a731286 | 2009-09-21 17:01:37 -0700 | [diff] [blame] | 1683 | __mod_zone_page_state(zone, NR_ISOLATED_ANON + file, nr_taken); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1684 | spin_unlock_irq(&zone->lru_lock); |
| 1685 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1686 | while (!list_empty(&l_hold)) { |
| 1687 | cond_resched(); |
| 1688 | page = lru_to_page(&l_hold); |
| 1689 | list_del(&page->lru); |
Rik van Riel | 7e9cd48 | 2008-10-18 20:26:35 -0700 | [diff] [blame] | 1690 | |
Hugh Dickins | 39b5f29 | 2012-10-08 16:33:18 -0700 | [diff] [blame] | 1691 | if (unlikely(!page_evictable(page))) { |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 1692 | putback_lru_page(page); |
| 1693 | continue; |
| 1694 | } |
| 1695 | |
Mel Gorman | cc715d9 | 2012-03-21 16:34:00 -0700 | [diff] [blame] | 1696 | if (unlikely(buffer_heads_over_limit)) { |
| 1697 | if (page_has_private(page) && trylock_page(page)) { |
| 1698 | if (page_has_private(page)) |
| 1699 | try_to_release_page(page, 0); |
| 1700 | unlock_page(page); |
| 1701 | } |
| 1702 | } |
| 1703 | |
Johannes Weiner | c3ac9a8 | 2012-05-29 15:06:25 -0700 | [diff] [blame] | 1704 | if (page_referenced(page, 0, sc->target_mem_cgroup, |
| 1705 | &vm_flags)) { |
Rik van Riel | 9992af1 | 2011-01-13 15:47:13 -0800 | [diff] [blame] | 1706 | nr_rotated += hpage_nr_pages(page); |
Wu Fengguang | 8cab475 | 2009-06-16 15:33:12 -0700 | [diff] [blame] | 1707 | /* |
| 1708 | * Identify referenced, file-backed active pages and |
| 1709 | * give them one more trip around the active list. So |
| 1710 | * that executable code get better chances to stay in |
| 1711 | * memory under moderate memory pressure. Anon pages |
| 1712 | * are not likely to be evicted by use-once streaming |
| 1713 | * IO, plus JVM can create lots of anon VM_EXEC pages, |
| 1714 | * so we ignore them here. |
| 1715 | */ |
Wu Fengguang | 41e2098 | 2009-10-26 16:49:53 -0700 | [diff] [blame] | 1716 | if ((vm_flags & VM_EXEC) && page_is_file_cache(page)) { |
Wu Fengguang | 8cab475 | 2009-06-16 15:33:12 -0700 | [diff] [blame] | 1717 | list_add(&page->lru, &l_active); |
| 1718 | continue; |
| 1719 | } |
| 1720 | } |
Rik van Riel | 7e9cd48 | 2008-10-18 20:26:35 -0700 | [diff] [blame] | 1721 | |
KOSAKI Motohiro | 5205e56 | 2009-09-21 17:01:44 -0700 | [diff] [blame] | 1722 | ClearPageActive(page); /* we are de-activating */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1723 | list_add(&page->lru, &l_inactive); |
| 1724 | } |
| 1725 | |
Andrew Morton | b555749 | 2009-01-06 14:40:13 -0800 | [diff] [blame] | 1726 | /* |
Wu Fengguang | 8cab475 | 2009-06-16 15:33:12 -0700 | [diff] [blame] | 1727 | * Move pages back to the lru list. |
Andrew Morton | b555749 | 2009-01-06 14:40:13 -0800 | [diff] [blame] | 1728 | */ |
Johannes Weiner | 2a1dc50 | 2008-12-01 03:00:35 +0100 | [diff] [blame] | 1729 | spin_lock_irq(&zone->lru_lock); |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1730 | /* |
Wu Fengguang | 8cab475 | 2009-06-16 15:33:12 -0700 | [diff] [blame] | 1731 | * Count referenced pages from currently used mappings as rotated, |
| 1732 | * even though only some of them are actually re-activated. This |
| 1733 | * helps balance scan pressure between file and anonymous pages in |
| 1734 | * get_scan_ratio. |
Rik van Riel | 7e9cd48 | 2008-10-18 20:26:35 -0700 | [diff] [blame] | 1735 | */ |
Johannes Weiner | b7c46d1 | 2009-09-21 17:02:56 -0700 | [diff] [blame] | 1736 | reclaim_stat->recent_rotated[file] += nr_rotated; |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 1737 | |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1738 | move_active_pages_to_lru(lruvec, &l_active, &l_hold, lru); |
| 1739 | move_active_pages_to_lru(lruvec, &l_inactive, &l_hold, lru - LRU_ACTIVE); |
KOSAKI Motohiro | a731286 | 2009-09-21 17:01:37 -0700 | [diff] [blame] | 1740 | __mod_zone_page_state(zone, NR_ISOLATED_ANON + file, -nr_taken); |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 1741 | spin_unlock_irq(&zone->lru_lock); |
Hugh Dickins | 2bcf887 | 2012-01-12 17:19:56 -0800 | [diff] [blame] | 1742 | |
| 1743 | free_hot_cold_page_list(&l_hold, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1744 | } |
| 1745 | |
Minchan Kim | 74e3f3c | 2010-10-26 14:21:31 -0700 | [diff] [blame] | 1746 | #ifdef CONFIG_SWAP |
KOSAKI Motohiro | 14797e2 | 2009-01-07 18:08:18 -0800 | [diff] [blame] | 1747 | static int inactive_anon_is_low_global(struct zone *zone) |
KOSAKI Motohiro | f89eb90 | 2009-01-07 18:08:14 -0800 | [diff] [blame] | 1748 | { |
| 1749 | unsigned long active, inactive; |
| 1750 | |
| 1751 | active = zone_page_state(zone, NR_ACTIVE_ANON); |
| 1752 | inactive = zone_page_state(zone, NR_INACTIVE_ANON); |
| 1753 | |
| 1754 | if (inactive * zone->inactive_ratio < active) |
| 1755 | return 1; |
| 1756 | |
| 1757 | return 0; |
| 1758 | } |
| 1759 | |
KOSAKI Motohiro | 14797e2 | 2009-01-07 18:08:18 -0800 | [diff] [blame] | 1760 | /** |
| 1761 | * inactive_anon_is_low - check if anonymous pages need to be deactivated |
Konstantin Khlebnikov | c56d5c7 | 2012-05-29 15:07:00 -0700 | [diff] [blame] | 1762 | * @lruvec: LRU vector to check |
KOSAKI Motohiro | 14797e2 | 2009-01-07 18:08:18 -0800 | [diff] [blame] | 1763 | * |
| 1764 | * Returns true if the zone does not have enough inactive anon pages, |
| 1765 | * meaning some active anon pages need to be deactivated. |
| 1766 | */ |
Konstantin Khlebnikov | c56d5c7 | 2012-05-29 15:07:00 -0700 | [diff] [blame] | 1767 | static int inactive_anon_is_low(struct lruvec *lruvec) |
KOSAKI Motohiro | 14797e2 | 2009-01-07 18:08:18 -0800 | [diff] [blame] | 1768 | { |
Minchan Kim | 74e3f3c | 2010-10-26 14:21:31 -0700 | [diff] [blame] | 1769 | /* |
| 1770 | * If we don't have swap space, anonymous page deactivation |
| 1771 | * is pointless. |
| 1772 | */ |
| 1773 | if (!total_swap_pages) |
| 1774 | return 0; |
| 1775 | |
Hugh Dickins | c3c787e | 2012-05-29 15:06:52 -0700 | [diff] [blame] | 1776 | if (!mem_cgroup_disabled()) |
Konstantin Khlebnikov | c56d5c7 | 2012-05-29 15:07:00 -0700 | [diff] [blame] | 1777 | return mem_cgroup_inactive_anon_is_low(lruvec); |
Johannes Weiner | f16015f | 2012-01-12 17:17:52 -0800 | [diff] [blame] | 1778 | |
Konstantin Khlebnikov | c56d5c7 | 2012-05-29 15:07:00 -0700 | [diff] [blame] | 1779 | return inactive_anon_is_low_global(lruvec_zone(lruvec)); |
KOSAKI Motohiro | 14797e2 | 2009-01-07 18:08:18 -0800 | [diff] [blame] | 1780 | } |
Minchan Kim | 74e3f3c | 2010-10-26 14:21:31 -0700 | [diff] [blame] | 1781 | #else |
Konstantin Khlebnikov | c56d5c7 | 2012-05-29 15:07:00 -0700 | [diff] [blame] | 1782 | static inline int inactive_anon_is_low(struct lruvec *lruvec) |
Minchan Kim | 74e3f3c | 2010-10-26 14:21:31 -0700 | [diff] [blame] | 1783 | { |
| 1784 | return 0; |
| 1785 | } |
| 1786 | #endif |
KOSAKI Motohiro | 14797e2 | 2009-01-07 18:08:18 -0800 | [diff] [blame] | 1787 | |
Rik van Riel | 56e49d2 | 2009-06-16 15:32:28 -0700 | [diff] [blame] | 1788 | /** |
| 1789 | * inactive_file_is_low - check if file pages need to be deactivated |
Konstantin Khlebnikov | c56d5c7 | 2012-05-29 15:07:00 -0700 | [diff] [blame] | 1790 | * @lruvec: LRU vector to check |
Rik van Riel | 56e49d2 | 2009-06-16 15:32:28 -0700 | [diff] [blame] | 1791 | * |
| 1792 | * When the system is doing streaming IO, memory pressure here |
| 1793 | * ensures that active file pages get deactivated, until more |
| 1794 | * than half of the file pages are on the inactive list. |
| 1795 | * |
| 1796 | * Once we get to that situation, protect the system's working |
| 1797 | * set from being evicted by disabling active file page aging. |
| 1798 | * |
| 1799 | * This uses a different ratio than the anonymous pages, because |
| 1800 | * the page cache uses a use-once replacement algorithm. |
| 1801 | */ |
Konstantin Khlebnikov | c56d5c7 | 2012-05-29 15:07:00 -0700 | [diff] [blame] | 1802 | static int inactive_file_is_low(struct lruvec *lruvec) |
Rik van Riel | 56e49d2 | 2009-06-16 15:32:28 -0700 | [diff] [blame] | 1803 | { |
Johannes Weiner | e379014 | 2013-02-22 16:35:19 -0800 | [diff] [blame] | 1804 | unsigned long inactive; |
| 1805 | unsigned long active; |
Rik van Riel | 56e49d2 | 2009-06-16 15:32:28 -0700 | [diff] [blame] | 1806 | |
Johannes Weiner | e379014 | 2013-02-22 16:35:19 -0800 | [diff] [blame] | 1807 | inactive = get_lru_size(lruvec, LRU_INACTIVE_FILE); |
| 1808 | active = get_lru_size(lruvec, LRU_ACTIVE_FILE); |
| 1809 | |
| 1810 | return active > inactive; |
Rik van Riel | 56e49d2 | 2009-06-16 15:32:28 -0700 | [diff] [blame] | 1811 | } |
| 1812 | |
Hugh Dickins | 75b00af | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1813 | static int inactive_list_is_low(struct lruvec *lruvec, enum lru_list lru) |
Rik van Riel | b39415b | 2009-12-14 17:59:48 -0800 | [diff] [blame] | 1814 | { |
Hugh Dickins | 75b00af | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1815 | if (is_file_lru(lru)) |
Konstantin Khlebnikov | c56d5c7 | 2012-05-29 15:07:00 -0700 | [diff] [blame] | 1816 | return inactive_file_is_low(lruvec); |
Rik van Riel | b39415b | 2009-12-14 17:59:48 -0800 | [diff] [blame] | 1817 | else |
Konstantin Khlebnikov | c56d5c7 | 2012-05-29 15:07:00 -0700 | [diff] [blame] | 1818 | return inactive_anon_is_low(lruvec); |
Rik van Riel | b39415b | 2009-12-14 17:59:48 -0800 | [diff] [blame] | 1819 | } |
| 1820 | |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1821 | static unsigned long shrink_list(enum lru_list lru, unsigned long nr_to_scan, |
Konstantin Khlebnikov | 1a93be0 | 2012-05-29 15:07:01 -0700 | [diff] [blame] | 1822 | struct lruvec *lruvec, struct scan_control *sc) |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1823 | { |
Rik van Riel | b39415b | 2009-12-14 17:59:48 -0800 | [diff] [blame] | 1824 | if (is_active_lru(lru)) { |
Hugh Dickins | 75b00af | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1825 | if (inactive_list_is_low(lruvec, lru)) |
Konstantin Khlebnikov | 1a93be0 | 2012-05-29 15:07:01 -0700 | [diff] [blame] | 1826 | shrink_active_list(nr_to_scan, lruvec, sc, lru); |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 1827 | return 0; |
| 1828 | } |
| 1829 | |
Konstantin Khlebnikov | 1a93be0 | 2012-05-29 15:07:01 -0700 | [diff] [blame] | 1830 | return shrink_inactive_list(nr_to_scan, lruvec, sc, lru); |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1831 | } |
| 1832 | |
Konstantin Khlebnikov | 3d58ab5 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 1833 | static int vmscan_swappiness(struct scan_control *sc) |
KAMEZAWA Hiroyuki | 1f4c025 | 2011-07-26 16:08:21 -0700 | [diff] [blame] | 1834 | { |
Johannes Weiner | 89b5fae | 2012-01-12 17:17:50 -0800 | [diff] [blame] | 1835 | if (global_reclaim(sc)) |
KAMEZAWA Hiroyuki | 1f4c025 | 2011-07-26 16:08:21 -0700 | [diff] [blame] | 1836 | return vm_swappiness; |
Konstantin Khlebnikov | 3d58ab5 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 1837 | return mem_cgroup_swappiness(sc->target_mem_cgroup); |
KAMEZAWA Hiroyuki | 1f4c025 | 2011-07-26 16:08:21 -0700 | [diff] [blame] | 1838 | } |
| 1839 | |
Johannes Weiner | 9a26511 | 2013-02-22 16:32:17 -0800 | [diff] [blame] | 1840 | enum scan_balance { |
| 1841 | SCAN_EQUAL, |
| 1842 | SCAN_FRACT, |
| 1843 | SCAN_ANON, |
| 1844 | SCAN_FILE, |
| 1845 | }; |
| 1846 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1847 | /* |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1848 | * Determine how aggressively the anon and file LRU lists should be |
| 1849 | * scanned. The relative value of each set of LRU lists is determined |
| 1850 | * by looking at the fraction of the pages scanned we did rotate back |
| 1851 | * onto the active list instead of evict. |
| 1852 | * |
Wanpeng Li | be7bd59 | 2012-06-14 20:41:02 +0800 | [diff] [blame] | 1853 | * nr[0] = anon inactive pages to scan; nr[1] = anon active pages to scan |
| 1854 | * nr[2] = file inactive pages to scan; nr[3] = file active pages to scan |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1855 | */ |
Konstantin Khlebnikov | 9012637 | 2012-05-29 15:07:01 -0700 | [diff] [blame] | 1856 | static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc, |
Konstantin Khlebnikov | 9e3b2f8 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 1857 | unsigned long *nr) |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1858 | { |
Konstantin Khlebnikov | 9012637 | 2012-05-29 15:07:01 -0700 | [diff] [blame] | 1859 | struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat; |
Johannes Weiner | 9a26511 | 2013-02-22 16:32:17 -0800 | [diff] [blame] | 1860 | u64 fraction[2]; |
| 1861 | u64 denominator = 0; /* gcc */ |
Konstantin Khlebnikov | 9012637 | 2012-05-29 15:07:01 -0700 | [diff] [blame] | 1862 | struct zone *zone = lruvec_zone(lruvec); |
Johannes Weiner | 9a26511 | 2013-02-22 16:32:17 -0800 | [diff] [blame] | 1863 | unsigned long anon_prio, file_prio; |
| 1864 | enum scan_balance scan_balance; |
Johannes Weiner | 0bf1457 | 2014-04-08 16:04:10 -0700 | [diff] [blame] | 1865 | unsigned long anon, file; |
Johannes Weiner | 9a26511 | 2013-02-22 16:32:17 -0800 | [diff] [blame] | 1866 | bool force_scan = false; |
| 1867 | unsigned long ap, fp; |
| 1868 | enum lru_list lru; |
Suleiman Souhlal | 6f04f48 | 2014-06-04 16:06:44 -0700 | [diff] [blame] | 1869 | bool some_scanned; |
| 1870 | int pass; |
KAMEZAWA Hiroyuki | 246e87a | 2011-05-26 16:25:34 -0700 | [diff] [blame] | 1871 | |
Johannes Weiner | f11c0ca | 2011-10-31 17:07:27 -0700 | [diff] [blame] | 1872 | /* |
| 1873 | * If the zone or memcg is small, nr[l] can be 0. This |
| 1874 | * results in no scanning on this priority and a potential |
| 1875 | * priority drop. Global direct reclaim can go to the next |
| 1876 | * zone and tends to have no problems. Global kswapd is for |
| 1877 | * zone balancing and it needs to scan a minimum amount. When |
| 1878 | * reclaiming for a memcg, a priority drop can cause high |
| 1879 | * latencies, so it's better to scan a minimum amount there as |
| 1880 | * well. |
| 1881 | */ |
Lisa Du | 6e543d5 | 2013-09-11 14:22:36 -0700 | [diff] [blame] | 1882 | if (current_is_kswapd() && !zone_reclaimable(zone)) |
Johannes Weiner | a4d3e9e | 2011-09-14 16:21:52 -0700 | [diff] [blame] | 1883 | force_scan = true; |
Johannes Weiner | 89b5fae | 2012-01-12 17:17:50 -0800 | [diff] [blame] | 1884 | if (!global_reclaim(sc)) |
Johannes Weiner | a4d3e9e | 2011-09-14 16:21:52 -0700 | [diff] [blame] | 1885 | force_scan = true; |
Shaohua Li | 76a33fc | 2010-05-24 14:32:36 -0700 | [diff] [blame] | 1886 | |
| 1887 | /* If we have no swap space, do not bother scanning anon pages. */ |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 1888 | if (!sc->may_swap || (get_nr_swap_pages() <= 0)) { |
Johannes Weiner | 9a26511 | 2013-02-22 16:32:17 -0800 | [diff] [blame] | 1889 | scan_balance = SCAN_FILE; |
Shaohua Li | 76a33fc | 2010-05-24 14:32:36 -0700 | [diff] [blame] | 1890 | goto out; |
| 1891 | } |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1892 | |
Johannes Weiner | 10316b3 | 2013-02-22 16:32:14 -0800 | [diff] [blame] | 1893 | /* |
| 1894 | * Global reclaim will swap to prevent OOM even with no |
| 1895 | * swappiness, but memcg users want to use this knob to |
| 1896 | * disable swapping for individual groups completely when |
| 1897 | * using the memory controller's swap limit feature would be |
| 1898 | * too expensive. |
| 1899 | */ |
| 1900 | if (!global_reclaim(sc) && !vmscan_swappiness(sc)) { |
Johannes Weiner | 9a26511 | 2013-02-22 16:32:17 -0800 | [diff] [blame] | 1901 | scan_balance = SCAN_FILE; |
Johannes Weiner | 10316b3 | 2013-02-22 16:32:14 -0800 | [diff] [blame] | 1902 | goto out; |
| 1903 | } |
| 1904 | |
| 1905 | /* |
| 1906 | * Do not apply any pressure balancing cleverness when the |
| 1907 | * system is close to OOM, scan both anon and file equally |
| 1908 | * (unless the swappiness setting disagrees with swapping). |
| 1909 | */ |
| 1910 | if (!sc->priority && vmscan_swappiness(sc)) { |
Johannes Weiner | 9a26511 | 2013-02-22 16:32:17 -0800 | [diff] [blame] | 1911 | scan_balance = SCAN_EQUAL; |
Johannes Weiner | 10316b3 | 2013-02-22 16:32:14 -0800 | [diff] [blame] | 1912 | goto out; |
| 1913 | } |
| 1914 | |
Hugh Dickins | 4d7dcca | 2012-05-29 15:07:08 -0700 | [diff] [blame] | 1915 | anon = get_lru_size(lruvec, LRU_ACTIVE_ANON) + |
| 1916 | get_lru_size(lruvec, LRU_INACTIVE_ANON); |
| 1917 | file = get_lru_size(lruvec, LRU_ACTIVE_FILE) + |
| 1918 | get_lru_size(lruvec, LRU_INACTIVE_FILE); |
Johannes Weiner | a4d3e9e | 2011-09-14 16:21:52 -0700 | [diff] [blame] | 1919 | |
Johannes Weiner | 11d16c2 | 2013-02-22 16:32:15 -0800 | [diff] [blame] | 1920 | /* |
Johannes Weiner | 6237625 | 2014-05-06 12:50:07 -0700 | [diff] [blame] | 1921 | * Prevent the reclaimer from falling into the cache trap: as |
| 1922 | * cache pages start out inactive, every cache fault will tip |
| 1923 | * the scan balance towards the file LRU. And as the file LRU |
| 1924 | * shrinks, so does the window for rotation from references. |
| 1925 | * This means we have a runaway feedback loop where a tiny |
| 1926 | * thrashing file LRU becomes infinitely more attractive than |
| 1927 | * anon pages. Try to detect this based on file LRU size. |
| 1928 | */ |
| 1929 | if (global_reclaim(sc)) { |
| 1930 | unsigned long free = zone_page_state(zone, NR_FREE_PAGES); |
| 1931 | |
| 1932 | if (unlikely(file + free <= high_wmark_pages(zone))) { |
| 1933 | scan_balance = SCAN_ANON; |
| 1934 | goto out; |
| 1935 | } |
| 1936 | } |
| 1937 | |
| 1938 | /* |
Johannes Weiner | 7c5bd70 | 2013-02-22 16:32:10 -0800 | [diff] [blame] | 1939 | * There is enough inactive page cache, do not reclaim |
| 1940 | * anything from the anonymous working set right now. |
| 1941 | */ |
| 1942 | if (!inactive_file_is_low(lruvec)) { |
Johannes Weiner | 9a26511 | 2013-02-22 16:32:17 -0800 | [diff] [blame] | 1943 | scan_balance = SCAN_FILE; |
Johannes Weiner | 7c5bd70 | 2013-02-22 16:32:10 -0800 | [diff] [blame] | 1944 | goto out; |
| 1945 | } |
| 1946 | |
Johannes Weiner | 9a26511 | 2013-02-22 16:32:17 -0800 | [diff] [blame] | 1947 | scan_balance = SCAN_FRACT; |
| 1948 | |
Johannes Weiner | 7c5bd70 | 2013-02-22 16:32:10 -0800 | [diff] [blame] | 1949 | /* |
KOSAKI Motohiro | 58c37f6 | 2010-08-09 17:19:51 -0700 | [diff] [blame] | 1950 | * With swappiness at 100, anonymous and file have the same priority. |
| 1951 | * This scanning priority is essentially the inverse of IO cost. |
| 1952 | */ |
Konstantin Khlebnikov | 3d58ab5 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 1953 | anon_prio = vmscan_swappiness(sc); |
Hugh Dickins | 75b00af | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1954 | file_prio = 200 - anon_prio; |
KOSAKI Motohiro | 58c37f6 | 2010-08-09 17:19:51 -0700 | [diff] [blame] | 1955 | |
| 1956 | /* |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1957 | * OK, so we have swap space and a fair amount of page cache |
| 1958 | * pages. We use the recently rotated / recently scanned |
| 1959 | * ratios to determine how valuable each cache is. |
| 1960 | * |
| 1961 | * Because workloads change over time (and to avoid overflow) |
| 1962 | * we keep these statistics as a floating average, which ends |
| 1963 | * up weighing recent references more than old ones. |
| 1964 | * |
| 1965 | * anon in [0], file in [1] |
| 1966 | */ |
Konstantin Khlebnikov | 9012637 | 2012-05-29 15:07:01 -0700 | [diff] [blame] | 1967 | spin_lock_irq(&zone->lru_lock); |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1968 | if (unlikely(reclaim_stat->recent_scanned[0] > anon / 4)) { |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1969 | reclaim_stat->recent_scanned[0] /= 2; |
| 1970 | reclaim_stat->recent_rotated[0] /= 2; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1971 | } |
| 1972 | |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1973 | if (unlikely(reclaim_stat->recent_scanned[1] > file / 4)) { |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1974 | reclaim_stat->recent_scanned[1] /= 2; |
| 1975 | reclaim_stat->recent_rotated[1] /= 2; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1976 | } |
| 1977 | |
| 1978 | /* |
Rik van Riel | 00d8089 | 2008-11-19 15:36:44 -0800 | [diff] [blame] | 1979 | * The amount of pressure on anon vs file pages is inversely |
| 1980 | * proportional to the fraction of recently scanned pages on |
| 1981 | * each list that were recently referenced and in active use. |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1982 | */ |
Satoru Moriya | fe35004 | 2012-05-29 15:06:47 -0700 | [diff] [blame] | 1983 | ap = anon_prio * (reclaim_stat->recent_scanned[0] + 1); |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1984 | ap /= reclaim_stat->recent_rotated[0] + 1; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1985 | |
Satoru Moriya | fe35004 | 2012-05-29 15:06:47 -0700 | [diff] [blame] | 1986 | fp = file_prio * (reclaim_stat->recent_scanned[1] + 1); |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1987 | fp /= reclaim_stat->recent_rotated[1] + 1; |
Konstantin Khlebnikov | 9012637 | 2012-05-29 15:07:01 -0700 | [diff] [blame] | 1988 | spin_unlock_irq(&zone->lru_lock); |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1989 | |
Shaohua Li | 76a33fc | 2010-05-24 14:32:36 -0700 | [diff] [blame] | 1990 | fraction[0] = ap; |
| 1991 | fraction[1] = fp; |
| 1992 | denominator = ap + fp + 1; |
| 1993 | out: |
Suleiman Souhlal | 6f04f48 | 2014-06-04 16:06:44 -0700 | [diff] [blame] | 1994 | some_scanned = false; |
| 1995 | /* Only use force_scan on second pass. */ |
| 1996 | for (pass = 0; !some_scanned && pass < 2; pass++) { |
| 1997 | for_each_evictable_lru(lru) { |
| 1998 | int file = is_file_lru(lru); |
| 1999 | unsigned long size; |
| 2000 | unsigned long scan; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 2001 | |
Suleiman Souhlal | 6f04f48 | 2014-06-04 16:06:44 -0700 | [diff] [blame] | 2002 | size = get_lru_size(lruvec, lru); |
| 2003 | scan = size >> sc->priority; |
Johannes Weiner | 9a26511 | 2013-02-22 16:32:17 -0800 | [diff] [blame] | 2004 | |
Suleiman Souhlal | 6f04f48 | 2014-06-04 16:06:44 -0700 | [diff] [blame] | 2005 | if (!scan && pass && force_scan) |
| 2006 | scan = min(size, SWAP_CLUSTER_MAX); |
Johannes Weiner | 9a26511 | 2013-02-22 16:32:17 -0800 | [diff] [blame] | 2007 | |
Suleiman Souhlal | 6f04f48 | 2014-06-04 16:06:44 -0700 | [diff] [blame] | 2008 | switch (scan_balance) { |
| 2009 | case SCAN_EQUAL: |
| 2010 | /* Scan lists relative to size */ |
| 2011 | break; |
| 2012 | case SCAN_FRACT: |
| 2013 | /* |
| 2014 | * Scan types proportional to swappiness and |
| 2015 | * their relative recent reclaim efficiency. |
| 2016 | */ |
| 2017 | scan = div64_u64(scan * fraction[file], |
| 2018 | denominator); |
| 2019 | break; |
| 2020 | case SCAN_FILE: |
| 2021 | case SCAN_ANON: |
| 2022 | /* Scan one type exclusively */ |
| 2023 | if ((scan_balance == SCAN_FILE) != file) |
| 2024 | scan = 0; |
| 2025 | break; |
| 2026 | default: |
| 2027 | /* Look ma, no brain */ |
| 2028 | BUG(); |
| 2029 | } |
| 2030 | nr[lru] = scan; |
Johannes Weiner | 9a26511 | 2013-02-22 16:32:17 -0800 | [diff] [blame] | 2031 | /* |
Suleiman Souhlal | 6f04f48 | 2014-06-04 16:06:44 -0700 | [diff] [blame] | 2032 | * Skip the second pass and don't force_scan, |
| 2033 | * if we found something to scan. |
Johannes Weiner | 9a26511 | 2013-02-22 16:32:17 -0800 | [diff] [blame] | 2034 | */ |
Suleiman Souhlal | 6f04f48 | 2014-06-04 16:06:44 -0700 | [diff] [blame] | 2035 | some_scanned |= !!scan; |
Johannes Weiner | 9a26511 | 2013-02-22 16:32:17 -0800 | [diff] [blame] | 2036 | } |
Shaohua Li | 76a33fc | 2010-05-24 14:32:36 -0700 | [diff] [blame] | 2037 | } |
Wu Fengguang | 6e08a36 | 2009-06-16 15:32:29 -0700 | [diff] [blame] | 2038 | } |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 2039 | |
Johannes Weiner | 9b4f98c | 2013-02-22 16:32:19 -0800 | [diff] [blame] | 2040 | /* |
| 2041 | * This is a basic per-zone page freer. Used by both kswapd and direct reclaim. |
| 2042 | */ |
| 2043 | static void shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc) |
| 2044 | { |
| 2045 | unsigned long nr[NR_LRU_LISTS]; |
Mel Gorman | e82e056 | 2013-07-03 15:01:44 -0700 | [diff] [blame] | 2046 | unsigned long targets[NR_LRU_LISTS]; |
Johannes Weiner | 9b4f98c | 2013-02-22 16:32:19 -0800 | [diff] [blame] | 2047 | unsigned long nr_to_scan; |
| 2048 | enum lru_list lru; |
| 2049 | unsigned long nr_reclaimed = 0; |
| 2050 | unsigned long nr_to_reclaim = sc->nr_to_reclaim; |
| 2051 | struct blk_plug plug; |
Mel Gorman | e82e056 | 2013-07-03 15:01:44 -0700 | [diff] [blame] | 2052 | bool scan_adjusted = false; |
Johannes Weiner | 9b4f98c | 2013-02-22 16:32:19 -0800 | [diff] [blame] | 2053 | |
| 2054 | get_scan_count(lruvec, sc, nr); |
| 2055 | |
Mel Gorman | e82e056 | 2013-07-03 15:01:44 -0700 | [diff] [blame] | 2056 | /* Record the original scan target for proportional adjustments later */ |
| 2057 | memcpy(targets, nr, sizeof(nr)); |
| 2058 | |
Johannes Weiner | 9b4f98c | 2013-02-22 16:32:19 -0800 | [diff] [blame] | 2059 | blk_start_plug(&plug); |
| 2060 | while (nr[LRU_INACTIVE_ANON] || nr[LRU_ACTIVE_FILE] || |
| 2061 | nr[LRU_INACTIVE_FILE]) { |
Mel Gorman | e82e056 | 2013-07-03 15:01:44 -0700 | [diff] [blame] | 2062 | unsigned long nr_anon, nr_file, percentage; |
| 2063 | unsigned long nr_scanned; |
| 2064 | |
Johannes Weiner | 9b4f98c | 2013-02-22 16:32:19 -0800 | [diff] [blame] | 2065 | for_each_evictable_lru(lru) { |
| 2066 | if (nr[lru]) { |
| 2067 | nr_to_scan = min(nr[lru], SWAP_CLUSTER_MAX); |
| 2068 | nr[lru] -= nr_to_scan; |
| 2069 | |
| 2070 | nr_reclaimed += shrink_list(lru, nr_to_scan, |
| 2071 | lruvec, sc); |
| 2072 | } |
| 2073 | } |
Mel Gorman | e82e056 | 2013-07-03 15:01:44 -0700 | [diff] [blame] | 2074 | |
| 2075 | if (nr_reclaimed < nr_to_reclaim || scan_adjusted) |
| 2076 | continue; |
| 2077 | |
Johannes Weiner | 9b4f98c | 2013-02-22 16:32:19 -0800 | [diff] [blame] | 2078 | /* |
Mel Gorman | e82e056 | 2013-07-03 15:01:44 -0700 | [diff] [blame] | 2079 | * For global direct reclaim, reclaim only the number of pages |
| 2080 | * requested. Less care is taken to scan proportionally as it |
| 2081 | * is more important to minimise direct reclaim stall latency |
| 2082 | * than it is to properly age the LRU lists. |
Johannes Weiner | 9b4f98c | 2013-02-22 16:32:19 -0800 | [diff] [blame] | 2083 | */ |
Mel Gorman | e82e056 | 2013-07-03 15:01:44 -0700 | [diff] [blame] | 2084 | if (global_reclaim(sc) && !current_is_kswapd()) |
Johannes Weiner | 9b4f98c | 2013-02-22 16:32:19 -0800 | [diff] [blame] | 2085 | break; |
Mel Gorman | e82e056 | 2013-07-03 15:01:44 -0700 | [diff] [blame] | 2086 | |
| 2087 | /* |
| 2088 | * For kswapd and memcg, reclaim at least the number of pages |
| 2089 | * requested. Ensure that the anon and file LRUs shrink |
| 2090 | * proportionally what was requested by get_scan_count(). We |
| 2091 | * stop reclaiming one LRU and reduce the amount scanning |
| 2092 | * proportional to the original scan target. |
| 2093 | */ |
| 2094 | nr_file = nr[LRU_INACTIVE_FILE] + nr[LRU_ACTIVE_FILE]; |
| 2095 | nr_anon = nr[LRU_INACTIVE_ANON] + nr[LRU_ACTIVE_ANON]; |
| 2096 | |
| 2097 | if (nr_file > nr_anon) { |
| 2098 | unsigned long scan_target = targets[LRU_INACTIVE_ANON] + |
| 2099 | targets[LRU_ACTIVE_ANON] + 1; |
| 2100 | lru = LRU_BASE; |
| 2101 | percentage = nr_anon * 100 / scan_target; |
| 2102 | } else { |
| 2103 | unsigned long scan_target = targets[LRU_INACTIVE_FILE] + |
| 2104 | targets[LRU_ACTIVE_FILE] + 1; |
| 2105 | lru = LRU_FILE; |
| 2106 | percentage = nr_file * 100 / scan_target; |
| 2107 | } |
| 2108 | |
| 2109 | /* Stop scanning the smaller of the LRU */ |
| 2110 | nr[lru] = 0; |
| 2111 | nr[lru + LRU_ACTIVE] = 0; |
| 2112 | |
| 2113 | /* |
| 2114 | * Recalculate the other LRU scan count based on its original |
| 2115 | * scan target and the percentage scanning already complete |
| 2116 | */ |
| 2117 | lru = (lru == LRU_FILE) ? LRU_BASE : LRU_FILE; |
| 2118 | nr_scanned = targets[lru] - nr[lru]; |
| 2119 | nr[lru] = targets[lru] * (100 - percentage) / 100; |
| 2120 | nr[lru] -= min(nr[lru], nr_scanned); |
| 2121 | |
| 2122 | lru += LRU_ACTIVE; |
| 2123 | nr_scanned = targets[lru] - nr[lru]; |
| 2124 | nr[lru] = targets[lru] * (100 - percentage) / 100; |
| 2125 | nr[lru] -= min(nr[lru], nr_scanned); |
| 2126 | |
| 2127 | scan_adjusted = true; |
Johannes Weiner | 9b4f98c | 2013-02-22 16:32:19 -0800 | [diff] [blame] | 2128 | } |
| 2129 | blk_finish_plug(&plug); |
| 2130 | sc->nr_reclaimed += nr_reclaimed; |
| 2131 | |
| 2132 | /* |
| 2133 | * Even if we did not try to evict anon pages at all, we want to |
| 2134 | * rebalance the anon lru active/inactive ratio. |
| 2135 | */ |
| 2136 | if (inactive_anon_is_low(lruvec)) |
| 2137 | shrink_active_list(SWAP_CLUSTER_MAX, lruvec, |
| 2138 | sc, LRU_ACTIVE_ANON); |
| 2139 | |
| 2140 | throttle_vm_writeout(sc->gfp_mask); |
| 2141 | } |
| 2142 | |
Mel Gorman | 23b9da5 | 2012-05-29 15:06:20 -0700 | [diff] [blame] | 2143 | /* Use reclaim/compaction for costly allocs or under memory pressure */ |
Konstantin Khlebnikov | 9e3b2f8 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 2144 | static bool in_reclaim_compaction(struct scan_control *sc) |
Mel Gorman | 23b9da5 | 2012-05-29 15:06:20 -0700 | [diff] [blame] | 2145 | { |
Kirill A. Shutemov | d84da3f | 2012-12-11 16:00:31 -0800 | [diff] [blame] | 2146 | if (IS_ENABLED(CONFIG_COMPACTION) && sc->order && |
Mel Gorman | 23b9da5 | 2012-05-29 15:06:20 -0700 | [diff] [blame] | 2147 | (sc->order > PAGE_ALLOC_COSTLY_ORDER || |
Konstantin Khlebnikov | 9e3b2f8 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 2148 | sc->priority < DEF_PRIORITY - 2)) |
Mel Gorman | 23b9da5 | 2012-05-29 15:06:20 -0700 | [diff] [blame] | 2149 | return true; |
| 2150 | |
| 2151 | return false; |
| 2152 | } |
| 2153 | |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 2154 | /* |
Mel Gorman | 23b9da5 | 2012-05-29 15:06:20 -0700 | [diff] [blame] | 2155 | * Reclaim/compaction is used for high-order allocation requests. It reclaims |
| 2156 | * order-0 pages before compacting the zone. should_continue_reclaim() returns |
| 2157 | * true if more pages should be reclaimed such that when the page allocator |
| 2158 | * calls try_to_compact_zone() that it will have enough free pages to succeed. |
| 2159 | * It will give up earlier than that if there is difficulty reclaiming pages. |
Mel Gorman | 3e7d344 | 2011-01-13 15:45:56 -0800 | [diff] [blame] | 2160 | */ |
Johannes Weiner | 9b4f98c | 2013-02-22 16:32:19 -0800 | [diff] [blame] | 2161 | static inline bool should_continue_reclaim(struct zone *zone, |
Mel Gorman | 3e7d344 | 2011-01-13 15:45:56 -0800 | [diff] [blame] | 2162 | unsigned long nr_reclaimed, |
| 2163 | unsigned long nr_scanned, |
| 2164 | struct scan_control *sc) |
| 2165 | { |
| 2166 | unsigned long pages_for_compaction; |
| 2167 | unsigned long inactive_lru_pages; |
| 2168 | |
| 2169 | /* If not in reclaim/compaction mode, stop */ |
Konstantin Khlebnikov | 9e3b2f8 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 2170 | if (!in_reclaim_compaction(sc)) |
Mel Gorman | 3e7d344 | 2011-01-13 15:45:56 -0800 | [diff] [blame] | 2171 | return false; |
| 2172 | |
Mel Gorman | 2876592 | 2011-02-25 14:44:20 -0800 | [diff] [blame] | 2173 | /* Consider stopping depending on scan and reclaim activity */ |
| 2174 | if (sc->gfp_mask & __GFP_REPEAT) { |
| 2175 | /* |
| 2176 | * For __GFP_REPEAT allocations, stop reclaiming if the |
| 2177 | * full LRU list has been scanned and we are still failing |
| 2178 | * to reclaim pages. This full LRU scan is potentially |
| 2179 | * expensive but a __GFP_REPEAT caller really wants to succeed |
| 2180 | */ |
| 2181 | if (!nr_reclaimed && !nr_scanned) |
| 2182 | return false; |
| 2183 | } else { |
| 2184 | /* |
| 2185 | * For non-__GFP_REPEAT allocations which can presumably |
| 2186 | * fail without consequence, stop if we failed to reclaim |
| 2187 | * any pages from the last SWAP_CLUSTER_MAX number of |
| 2188 | * pages that were scanned. This will return to the |
| 2189 | * caller faster at the risk reclaim/compaction and |
| 2190 | * the resulting allocation attempt fails |
| 2191 | */ |
| 2192 | if (!nr_reclaimed) |
| 2193 | return false; |
| 2194 | } |
Mel Gorman | 3e7d344 | 2011-01-13 15:45:56 -0800 | [diff] [blame] | 2195 | |
| 2196 | /* |
| 2197 | * If we have not reclaimed enough pages for compaction and the |
| 2198 | * inactive lists are large enough, continue reclaiming |
| 2199 | */ |
| 2200 | pages_for_compaction = (2UL << sc->order); |
Johannes Weiner | 9b4f98c | 2013-02-22 16:32:19 -0800 | [diff] [blame] | 2201 | inactive_lru_pages = zone_page_state(zone, NR_INACTIVE_FILE); |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 2202 | if (get_nr_swap_pages() > 0) |
Johannes Weiner | 9b4f98c | 2013-02-22 16:32:19 -0800 | [diff] [blame] | 2203 | inactive_lru_pages += zone_page_state(zone, NR_INACTIVE_ANON); |
Mel Gorman | 3e7d344 | 2011-01-13 15:45:56 -0800 | [diff] [blame] | 2204 | if (sc->nr_reclaimed < pages_for_compaction && |
| 2205 | inactive_lru_pages > pages_for_compaction) |
| 2206 | return true; |
| 2207 | |
| 2208 | /* If compaction would go ahead or the allocation would succeed, stop */ |
Johannes Weiner | 9b4f98c | 2013-02-22 16:32:19 -0800 | [diff] [blame] | 2209 | switch (compaction_suitable(zone, sc->order)) { |
Mel Gorman | 3e7d344 | 2011-01-13 15:45:56 -0800 | [diff] [blame] | 2210 | case COMPACT_PARTIAL: |
| 2211 | case COMPACT_CONTINUE: |
| 2212 | return false; |
| 2213 | default: |
| 2214 | return true; |
| 2215 | } |
| 2216 | } |
| 2217 | |
Andrew Morton | 0608f43 | 2013-09-24 15:27:41 -0700 | [diff] [blame] | 2218 | static void shrink_zone(struct zone *zone, struct scan_control *sc) |
Johannes Weiner | f16015f | 2012-01-12 17:17:52 -0800 | [diff] [blame] | 2219 | { |
Johannes Weiner | 9b4f98c | 2013-02-22 16:32:19 -0800 | [diff] [blame] | 2220 | unsigned long nr_reclaimed, nr_scanned; |
Johannes Weiner | f16015f | 2012-01-12 17:17:52 -0800 | [diff] [blame] | 2221 | |
Johannes Weiner | 5660048 | 2012-01-12 17:17:59 -0800 | [diff] [blame] | 2222 | do { |
Johannes Weiner | 9b4f98c | 2013-02-22 16:32:19 -0800 | [diff] [blame] | 2223 | struct mem_cgroup *root = sc->target_mem_cgroup; |
| 2224 | struct mem_cgroup_reclaim_cookie reclaim = { |
| 2225 | .zone = zone, |
| 2226 | .priority = sc->priority, |
| 2227 | }; |
Andrew Morton | 694fbc0 | 2013-09-24 15:27:37 -0700 | [diff] [blame] | 2228 | struct mem_cgroup *memcg; |
Johannes Weiner | 5660048 | 2012-01-12 17:17:59 -0800 | [diff] [blame] | 2229 | |
Johannes Weiner | 9b4f98c | 2013-02-22 16:32:19 -0800 | [diff] [blame] | 2230 | nr_reclaimed = sc->nr_reclaimed; |
| 2231 | nr_scanned = sc->nr_scanned; |
Konstantin Khlebnikov | f9be23d | 2012-05-29 15:07:02 -0700 | [diff] [blame] | 2232 | |
Andrew Morton | 694fbc0 | 2013-09-24 15:27:37 -0700 | [diff] [blame] | 2233 | memcg = mem_cgroup_iter(root, NULL, &reclaim); |
| 2234 | do { |
Johannes Weiner | 9b4f98c | 2013-02-22 16:32:19 -0800 | [diff] [blame] | 2235 | struct lruvec *lruvec; |
| 2236 | |
| 2237 | lruvec = mem_cgroup_zone_lruvec(zone, memcg); |
| 2238 | |
| 2239 | shrink_lruvec(lruvec, sc); |
| 2240 | |
| 2241 | /* |
Michal Hocko | a394cb8 | 2013-02-22 16:32:30 -0800 | [diff] [blame] | 2242 | * Direct reclaim and kswapd have to scan all memory |
| 2243 | * cgroups to fulfill the overall scan target for the |
Johannes Weiner | 9b4f98c | 2013-02-22 16:32:19 -0800 | [diff] [blame] | 2244 | * zone. |
Michal Hocko | a394cb8 | 2013-02-22 16:32:30 -0800 | [diff] [blame] | 2245 | * |
| 2246 | * Limit reclaim, on the other hand, only cares about |
| 2247 | * nr_to_reclaim pages to be reclaimed and it will |
| 2248 | * retry with decreasing priority if one round over the |
| 2249 | * whole hierarchy is not sufficient. |
Johannes Weiner | 9b4f98c | 2013-02-22 16:32:19 -0800 | [diff] [blame] | 2250 | */ |
Michal Hocko | a394cb8 | 2013-02-22 16:32:30 -0800 | [diff] [blame] | 2251 | if (!global_reclaim(sc) && |
| 2252 | sc->nr_reclaimed >= sc->nr_to_reclaim) { |
Johannes Weiner | 9b4f98c | 2013-02-22 16:32:19 -0800 | [diff] [blame] | 2253 | mem_cgroup_iter_break(root, memcg); |
| 2254 | break; |
| 2255 | } |
Andrew Morton | 694fbc0 | 2013-09-24 15:27:37 -0700 | [diff] [blame] | 2256 | memcg = mem_cgroup_iter(root, memcg, &reclaim); |
| 2257 | } while (memcg); |
Anton Vorontsov | 70ddf63 | 2013-04-29 15:08:31 -0700 | [diff] [blame] | 2258 | |
| 2259 | vmpressure(sc->gfp_mask, sc->target_mem_cgroup, |
| 2260 | sc->nr_scanned - nr_scanned, |
| 2261 | sc->nr_reclaimed - nr_reclaimed); |
| 2262 | |
Johannes Weiner | 9b4f98c | 2013-02-22 16:32:19 -0800 | [diff] [blame] | 2263 | } while (should_continue_reclaim(zone, sc->nr_reclaimed - nr_reclaimed, |
| 2264 | sc->nr_scanned - nr_scanned, sc)); |
Johannes Weiner | f16015f | 2012-01-12 17:17:52 -0800 | [diff] [blame] | 2265 | } |
| 2266 | |
Mel Gorman | fe4b1b2 | 2012-01-12 17:19:45 -0800 | [diff] [blame] | 2267 | /* Returns true if compaction should go ahead for a high-order request */ |
| 2268 | static inline bool compaction_ready(struct zone *zone, struct scan_control *sc) |
| 2269 | { |
| 2270 | unsigned long balance_gap, watermark; |
| 2271 | bool watermark_ok; |
| 2272 | |
| 2273 | /* Do not consider compaction for orders reclaim is meant to satisfy */ |
| 2274 | if (sc->order <= PAGE_ALLOC_COSTLY_ORDER) |
| 2275 | return false; |
| 2276 | |
| 2277 | /* |
| 2278 | * Compaction takes time to run and there are potentially other |
| 2279 | * callers using the pages just freed. Continue reclaiming until |
| 2280 | * there is a buffer of free pages available to give compaction |
| 2281 | * a reasonable chance of completing and allocating the page |
| 2282 | */ |
| 2283 | balance_gap = min(low_wmark_pages(zone), |
Jiang Liu | b40da04 | 2013-02-22 16:33:52 -0800 | [diff] [blame] | 2284 | (zone->managed_pages + KSWAPD_ZONE_BALANCE_GAP_RATIO-1) / |
Mel Gorman | fe4b1b2 | 2012-01-12 17:19:45 -0800 | [diff] [blame] | 2285 | KSWAPD_ZONE_BALANCE_GAP_RATIO); |
| 2286 | watermark = high_wmark_pages(zone) + balance_gap + (2UL << sc->order); |
| 2287 | watermark_ok = zone_watermark_ok_safe(zone, 0, watermark, 0, 0); |
| 2288 | |
| 2289 | /* |
| 2290 | * If compaction is deferred, reclaim up to a point where |
| 2291 | * compaction will have a chance of success when re-enabled |
| 2292 | */ |
Rik van Riel | aff6224 | 2012-03-21 16:33:52 -0700 | [diff] [blame] | 2293 | if (compaction_deferred(zone, sc->order)) |
Mel Gorman | fe4b1b2 | 2012-01-12 17:19:45 -0800 | [diff] [blame] | 2294 | return watermark_ok; |
| 2295 | |
| 2296 | /* If compaction is not ready to start, keep reclaiming */ |
| 2297 | if (!compaction_suitable(zone, sc->order)) |
| 2298 | return false; |
| 2299 | |
| 2300 | return watermark_ok; |
| 2301 | } |
| 2302 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2303 | /* |
| 2304 | * This is the direct reclaim path, for page-allocating processes. We only |
| 2305 | * try to reclaim pages from zones which will satisfy the caller's allocation |
| 2306 | * request. |
| 2307 | * |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 2308 | * We reclaim from a zone even if that zone is over high_wmark_pages(zone). |
| 2309 | * Because: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2310 | * a) The caller may be trying to free *extra* pages to satisfy a higher-order |
| 2311 | * allocation or |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 2312 | * b) The target zone may be at high_wmark_pages(zone) but the lower zones |
| 2313 | * must go *over* high_wmark_pages(zone) to satisfy the `incremental min' |
| 2314 | * zone defense algorithm. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2315 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2316 | * If a zone is deemed to be full of pinned pages then just give it a light |
| 2317 | * scan then give up on it. |
Mel Gorman | e0c2327 | 2011-10-31 17:09:33 -0700 | [diff] [blame] | 2318 | * |
| 2319 | * This function returns true if a zone is being reclaimed for a costly |
Mel Gorman | fe4b1b2 | 2012-01-12 17:19:45 -0800 | [diff] [blame] | 2320 | * high-order allocation and compaction is ready to begin. This indicates to |
Mel Gorman | 0cee34f | 2012-01-12 17:19:49 -0800 | [diff] [blame] | 2321 | * the caller that it should consider retrying the allocation instead of |
| 2322 | * further reclaim. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2323 | */ |
Vladimir Davydov | 3115cd9 | 2014-04-03 14:47:22 -0700 | [diff] [blame] | 2324 | static bool shrink_zones(struct zonelist *zonelist, struct scan_control *sc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2325 | { |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 2326 | struct zoneref *z; |
Mel Gorman | 54a6eb5 | 2008-04-28 02:12:16 -0700 | [diff] [blame] | 2327 | struct zone *zone; |
Andrew Morton | 0608f43 | 2013-09-24 15:27:41 -0700 | [diff] [blame] | 2328 | unsigned long nr_soft_reclaimed; |
| 2329 | unsigned long nr_soft_scanned; |
Vladimir Davydov | 65ec02c | 2014-04-03 14:47:20 -0700 | [diff] [blame] | 2330 | unsigned long lru_pages = 0; |
Mel Gorman | 0cee34f | 2012-01-12 17:19:49 -0800 | [diff] [blame] | 2331 | bool aborted_reclaim = false; |
Vladimir Davydov | 65ec02c | 2014-04-03 14:47:20 -0700 | [diff] [blame] | 2332 | struct reclaim_state *reclaim_state = current->reclaim_state; |
Weijie Yang | 619d0d76 | 2014-04-07 15:36:59 -0700 | [diff] [blame] | 2333 | gfp_t orig_mask; |
Vladimir Davydov | 3115cd9 | 2014-04-03 14:47:22 -0700 | [diff] [blame] | 2334 | struct shrink_control shrink = { |
| 2335 | .gfp_mask = sc->gfp_mask, |
| 2336 | }; |
Weijie Yang | 9bbc04e | 2014-04-07 15:37:00 -0700 | [diff] [blame] | 2337 | enum zone_type requested_highidx = gfp_zone(sc->gfp_mask); |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 2338 | |
Mel Gorman | cc715d9 | 2012-03-21 16:34:00 -0700 | [diff] [blame] | 2339 | /* |
| 2340 | * If the number of buffer_heads in the machine exceeds the maximum |
| 2341 | * allowed level, force direct reclaim to scan the highmem zone as |
| 2342 | * highmem pages could be pinning lowmem pages storing buffer_heads |
| 2343 | */ |
Weijie Yang | 619d0d76 | 2014-04-07 15:36:59 -0700 | [diff] [blame] | 2344 | orig_mask = sc->gfp_mask; |
Mel Gorman | cc715d9 | 2012-03-21 16:34:00 -0700 | [diff] [blame] | 2345 | if (buffer_heads_over_limit) |
| 2346 | sc->gfp_mask |= __GFP_HIGHMEM; |
| 2347 | |
Vladimir Davydov | 3115cd9 | 2014-04-03 14:47:22 -0700 | [diff] [blame] | 2348 | nodes_clear(shrink.nodes_to_scan); |
Vladimir Davydov | 65ec02c | 2014-04-03 14:47:20 -0700 | [diff] [blame] | 2349 | |
Mel Gorman | d4debc6 | 2010-08-09 17:19:29 -0700 | [diff] [blame] | 2350 | for_each_zone_zonelist_nodemask(zone, z, zonelist, |
| 2351 | gfp_zone(sc->gfp_mask), sc->nodemask) { |
Con Kolivas | f3fe651 | 2006-01-06 00:11:15 -0800 | [diff] [blame] | 2352 | if (!populated_zone(zone)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2353 | continue; |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 2354 | /* |
| 2355 | * Take care memory controller reclaiming has small influence |
| 2356 | * to global LRU. |
| 2357 | */ |
Johannes Weiner | 89b5fae | 2012-01-12 17:17:50 -0800 | [diff] [blame] | 2358 | if (global_reclaim(sc)) { |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 2359 | if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) |
| 2360 | continue; |
Vladimir Davydov | 65ec02c | 2014-04-03 14:47:20 -0700 | [diff] [blame] | 2361 | |
| 2362 | lru_pages += zone_reclaimable_pages(zone); |
Vladimir Davydov | 3115cd9 | 2014-04-03 14:47:22 -0700 | [diff] [blame] | 2363 | node_set(zone_to_nid(zone), shrink.nodes_to_scan); |
Vladimir Davydov | 65ec02c | 2014-04-03 14:47:20 -0700 | [diff] [blame] | 2364 | |
Lisa Du | 6e543d5 | 2013-09-11 14:22:36 -0700 | [diff] [blame] | 2365 | if (sc->priority != DEF_PRIORITY && |
| 2366 | !zone_reclaimable(zone)) |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 2367 | continue; /* Let kswapd poll it */ |
Kirill A. Shutemov | d84da3f | 2012-12-11 16:00:31 -0800 | [diff] [blame] | 2368 | if (IS_ENABLED(CONFIG_COMPACTION)) { |
Rik van Riel | e0887c1 | 2011-10-31 17:09:31 -0700 | [diff] [blame] | 2369 | /* |
Mel Gorman | e0c2327 | 2011-10-31 17:09:33 -0700 | [diff] [blame] | 2370 | * If we already have plenty of memory free for |
| 2371 | * compaction in this zone, don't free any more. |
| 2372 | * Even though compaction is invoked for any |
| 2373 | * non-zero order, only frequent costly order |
| 2374 | * reclamation is disruptive enough to become a |
Copot Alexandru | c7cfa37 | 2012-03-21 16:34:10 -0700 | [diff] [blame] | 2375 | * noticeable problem, like transparent huge |
| 2376 | * page allocations. |
Rik van Riel | e0887c1 | 2011-10-31 17:09:31 -0700 | [diff] [blame] | 2377 | */ |
Weijie Yang | 9bbc04e | 2014-04-07 15:37:00 -0700 | [diff] [blame] | 2378 | if ((zonelist_zone_idx(z) <= requested_highidx) |
| 2379 | && compaction_ready(zone, sc)) { |
Mel Gorman | 0cee34f | 2012-01-12 17:19:49 -0800 | [diff] [blame] | 2380 | aborted_reclaim = true; |
Rik van Riel | e0887c1 | 2011-10-31 17:09:31 -0700 | [diff] [blame] | 2381 | continue; |
Mel Gorman | e0c2327 | 2011-10-31 17:09:33 -0700 | [diff] [blame] | 2382 | } |
Rik van Riel | e0887c1 | 2011-10-31 17:09:31 -0700 | [diff] [blame] | 2383 | } |
Andrew Morton | 0608f43 | 2013-09-24 15:27:41 -0700 | [diff] [blame] | 2384 | /* |
| 2385 | * This steals pages from memory cgroups over softlimit |
| 2386 | * and returns the number of reclaimed pages and |
| 2387 | * scanned pages. This works for global memory pressure |
| 2388 | * and balancing, not for a memcg's limit. |
| 2389 | */ |
| 2390 | nr_soft_scanned = 0; |
| 2391 | nr_soft_reclaimed = mem_cgroup_soft_limit_reclaim(zone, |
| 2392 | sc->order, sc->gfp_mask, |
| 2393 | &nr_soft_scanned); |
| 2394 | sc->nr_reclaimed += nr_soft_reclaimed; |
| 2395 | sc->nr_scanned += nr_soft_scanned; |
KAMEZAWA Hiroyuki | ac34a1a | 2011-06-27 16:18:12 -0700 | [diff] [blame] | 2396 | /* need some check for avoid more shrink_zone() */ |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 2397 | } |
Nick Piggin | 408d854 | 2006-09-25 23:31:27 -0700 | [diff] [blame] | 2398 | |
Konstantin Khlebnikov | 9e3b2f8 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 2399 | shrink_zone(zone, sc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2400 | } |
Mel Gorman | e0c2327 | 2011-10-31 17:09:33 -0700 | [diff] [blame] | 2401 | |
Vladimir Davydov | 65ec02c | 2014-04-03 14:47:20 -0700 | [diff] [blame] | 2402 | /* |
| 2403 | * Don't shrink slabs when reclaiming memory from over limit cgroups |
| 2404 | * but do shrink slab at least once when aborting reclaim for |
| 2405 | * compaction to avoid unevenly scanning file/anon LRU pages over slab |
| 2406 | * pages. |
| 2407 | */ |
| 2408 | if (global_reclaim(sc)) { |
Vladimir Davydov | 3115cd9 | 2014-04-03 14:47:22 -0700 | [diff] [blame] | 2409 | shrink_slab(&shrink, sc->nr_scanned, lru_pages); |
Vladimir Davydov | 65ec02c | 2014-04-03 14:47:20 -0700 | [diff] [blame] | 2410 | if (reclaim_state) { |
| 2411 | sc->nr_reclaimed += reclaim_state->reclaimed_slab; |
| 2412 | reclaim_state->reclaimed_slab = 0; |
| 2413 | } |
| 2414 | } |
| 2415 | |
Weijie Yang | 619d0d76 | 2014-04-07 15:36:59 -0700 | [diff] [blame] | 2416 | /* |
| 2417 | * Restore to original mask to avoid the impact on the caller if we |
| 2418 | * promoted it to __GFP_HIGHMEM. |
| 2419 | */ |
| 2420 | sc->gfp_mask = orig_mask; |
| 2421 | |
Mel Gorman | 0cee34f | 2012-01-12 17:19:49 -0800 | [diff] [blame] | 2422 | return aborted_reclaim; |
Minchan Kim | d190836 | 2010-09-22 13:05:01 -0700 | [diff] [blame] | 2423 | } |
| 2424 | |
KOSAKI Motohiro | 929bea7 | 2011-04-14 15:22:12 -0700 | [diff] [blame] | 2425 | /* All zones in zonelist are unreclaimable? */ |
Minchan Kim | d190836 | 2010-09-22 13:05:01 -0700 | [diff] [blame] | 2426 | static bool all_unreclaimable(struct zonelist *zonelist, |
| 2427 | struct scan_control *sc) |
| 2428 | { |
| 2429 | struct zoneref *z; |
| 2430 | struct zone *zone; |
Minchan Kim | d190836 | 2010-09-22 13:05:01 -0700 | [diff] [blame] | 2431 | |
| 2432 | for_each_zone_zonelist_nodemask(zone, z, zonelist, |
| 2433 | gfp_zone(sc->gfp_mask), sc->nodemask) { |
| 2434 | if (!populated_zone(zone)) |
| 2435 | continue; |
| 2436 | if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) |
| 2437 | continue; |
Lisa Du | 6e543d5 | 2013-09-11 14:22:36 -0700 | [diff] [blame] | 2438 | if (zone_reclaimable(zone)) |
KOSAKI Motohiro | 929bea7 | 2011-04-14 15:22:12 -0700 | [diff] [blame] | 2439 | return false; |
Minchan Kim | d190836 | 2010-09-22 13:05:01 -0700 | [diff] [blame] | 2440 | } |
| 2441 | |
KOSAKI Motohiro | 929bea7 | 2011-04-14 15:22:12 -0700 | [diff] [blame] | 2442 | return true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2443 | } |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 2444 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2445 | /* |
| 2446 | * This is the main entry point to direct page reclaim. |
| 2447 | * |
| 2448 | * If a full scan of the inactive list fails to free enough memory then we |
| 2449 | * are "out of memory" and something needs to be killed. |
| 2450 | * |
| 2451 | * If the caller is !__GFP_FS then the probability of a failure is reasonably |
| 2452 | * high - the zone may be full of dirty or under-writeback pages, which this |
Jens Axboe | 5b0830c | 2009-09-23 19:37:09 +0200 | [diff] [blame] | 2453 | * caller can't do much about. We kick the writeback threads and take explicit |
| 2454 | * naps in the hope that some of these pages can be written. But if the |
| 2455 | * allocating task holds filesystem locks which prevent writeout this might not |
| 2456 | * work, and the allocation attempt will fail. |
Nishanth Aravamudan | a41f24e | 2008-04-29 00:58:25 -0700 | [diff] [blame] | 2457 | * |
| 2458 | * returns: 0, if no pages reclaimed |
| 2459 | * else, the number of pages reclaimed |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2460 | */ |
Mel Gorman | dac1d27 | 2008-04-28 02:12:12 -0700 | [diff] [blame] | 2461 | static unsigned long do_try_to_free_pages(struct zonelist *zonelist, |
Vladimir Davydov | 3115cd9 | 2014-04-03 14:47:22 -0700 | [diff] [blame] | 2462 | struct scan_control *sc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2463 | { |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 2464 | unsigned long total_scanned = 0; |
KOSAKI Motohiro | 22fba33 | 2009-12-14 17:59:10 -0800 | [diff] [blame] | 2465 | unsigned long writeback_threshold; |
Mel Gorman | 0cee34f | 2012-01-12 17:19:49 -0800 | [diff] [blame] | 2466 | bool aborted_reclaim; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2467 | |
Keika Kobayashi | 873b477 | 2008-07-25 01:48:52 -0700 | [diff] [blame] | 2468 | delayacct_freepages_start(); |
| 2469 | |
Johannes Weiner | 89b5fae | 2012-01-12 17:17:50 -0800 | [diff] [blame] | 2470 | if (global_reclaim(sc)) |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 2471 | count_vm_event(ALLOCSTALL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2472 | |
Konstantin Khlebnikov | 9e3b2f8 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 2473 | do { |
Anton Vorontsov | 70ddf63 | 2013-04-29 15:08:31 -0700 | [diff] [blame] | 2474 | vmpressure_prio(sc->gfp_mask, sc->target_mem_cgroup, |
| 2475 | sc->priority); |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2476 | sc->nr_scanned = 0; |
Vladimir Davydov | 3115cd9 | 2014-04-03 14:47:22 -0700 | [diff] [blame] | 2477 | aborted_reclaim = shrink_zones(zonelist, sc); |
Mel Gorman | e0c2327 | 2011-10-31 17:09:33 -0700 | [diff] [blame] | 2478 | |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2479 | total_scanned += sc->nr_scanned; |
KOSAKI Motohiro | bb21c7c | 2010-06-04 14:15:05 -0700 | [diff] [blame] | 2480 | if (sc->nr_reclaimed >= sc->nr_to_reclaim) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2481 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2482 | |
| 2483 | /* |
Minchan Kim | 0e50ce3 | 2013-02-22 16:35:37 -0800 | [diff] [blame] | 2484 | * If we're getting trouble reclaiming, start doing |
| 2485 | * writepage even in laptop mode. |
| 2486 | */ |
| 2487 | if (sc->priority < DEF_PRIORITY - 2) |
| 2488 | sc->may_writepage = 1; |
| 2489 | |
| 2490 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2491 | * Try to write back as many pages as we just scanned. This |
| 2492 | * tends to cause slow streaming writers to write data to the |
| 2493 | * disk smoothly, at the dirtying rate, which is nice. But |
| 2494 | * that's undesirable in laptop mode, where we *want* lumpy |
| 2495 | * writeout. So in laptop mode, write out the whole world. |
| 2496 | */ |
KOSAKI Motohiro | 22fba33 | 2009-12-14 17:59:10 -0800 | [diff] [blame] | 2497 | writeback_threshold = sc->nr_to_reclaim + sc->nr_to_reclaim / 2; |
| 2498 | if (total_scanned > writeback_threshold) { |
Curt Wohlgemuth | 0e175a1 | 2011-10-07 21:54:10 -0600 | [diff] [blame] | 2499 | wakeup_flusher_threads(laptop_mode ? 0 : total_scanned, |
| 2500 | WB_REASON_TRY_TO_FREE_PAGES); |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2501 | sc->may_writepage = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2502 | } |
Mel Gorman | 5a1c9cb | 2013-07-08 16:00:24 -0700 | [diff] [blame] | 2503 | } while (--sc->priority >= 0 && !aborted_reclaim); |
KOSAKI Motohiro | bb21c7c | 2010-06-04 14:15:05 -0700 | [diff] [blame] | 2504 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2505 | out: |
Keika Kobayashi | 873b477 | 2008-07-25 01:48:52 -0700 | [diff] [blame] | 2506 | delayacct_freepages_end(); |
| 2507 | |
KOSAKI Motohiro | bb21c7c | 2010-06-04 14:15:05 -0700 | [diff] [blame] | 2508 | if (sc->nr_reclaimed) |
| 2509 | return sc->nr_reclaimed; |
| 2510 | |
KOSAKI Motohiro | 929bea7 | 2011-04-14 15:22:12 -0700 | [diff] [blame] | 2511 | /* |
| 2512 | * As hibernation is going on, kswapd is freezed so that it can't mark |
| 2513 | * the zone into all_unreclaimable. Thus bypassing all_unreclaimable |
| 2514 | * check. |
| 2515 | */ |
| 2516 | if (oom_killer_disabled) |
| 2517 | return 0; |
| 2518 | |
Mel Gorman | 0cee34f | 2012-01-12 17:19:49 -0800 | [diff] [blame] | 2519 | /* Aborted reclaim to try compaction? don't OOM, then */ |
| 2520 | if (aborted_reclaim) |
Mel Gorman | 7335084 | 2012-01-12 17:19:33 -0800 | [diff] [blame] | 2521 | return 1; |
| 2522 | |
KOSAKI Motohiro | bb21c7c | 2010-06-04 14:15:05 -0700 | [diff] [blame] | 2523 | /* top priority shrink_zones still had more to do? don't OOM, then */ |
Johannes Weiner | 89b5fae | 2012-01-12 17:17:50 -0800 | [diff] [blame] | 2524 | if (global_reclaim(sc) && !all_unreclaimable(zonelist, sc)) |
KOSAKI Motohiro | bb21c7c | 2010-06-04 14:15:05 -0700 | [diff] [blame] | 2525 | return 1; |
| 2526 | |
| 2527 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2528 | } |
| 2529 | |
Mel Gorman | 5515061 | 2012-07-31 16:44:35 -0700 | [diff] [blame] | 2530 | static bool pfmemalloc_watermark_ok(pg_data_t *pgdat) |
| 2531 | { |
| 2532 | struct zone *zone; |
| 2533 | unsigned long pfmemalloc_reserve = 0; |
| 2534 | unsigned long free_pages = 0; |
| 2535 | int i; |
| 2536 | bool wmark_ok; |
| 2537 | |
| 2538 | for (i = 0; i <= ZONE_NORMAL; i++) { |
| 2539 | zone = &pgdat->node_zones[i]; |
| 2540 | pfmemalloc_reserve += min_wmark_pages(zone); |
| 2541 | free_pages += zone_page_state(zone, NR_FREE_PAGES); |
| 2542 | } |
| 2543 | |
| 2544 | wmark_ok = free_pages > pfmemalloc_reserve / 2; |
| 2545 | |
| 2546 | /* kswapd must be awake if processes are being throttled */ |
| 2547 | if (!wmark_ok && waitqueue_active(&pgdat->kswapd_wait)) { |
| 2548 | pgdat->classzone_idx = min(pgdat->classzone_idx, |
| 2549 | (enum zone_type)ZONE_NORMAL); |
| 2550 | wake_up_interruptible(&pgdat->kswapd_wait); |
| 2551 | } |
| 2552 | |
| 2553 | return wmark_ok; |
| 2554 | } |
| 2555 | |
| 2556 | /* |
| 2557 | * Throttle direct reclaimers if backing storage is backed by the network |
| 2558 | * and the PFMEMALLOC reserve for the preferred node is getting dangerously |
| 2559 | * depleted. kswapd will continue to make progress and wake the processes |
Mel Gorman | 50694c2 | 2012-11-26 16:29:48 -0800 | [diff] [blame] | 2560 | * when the low watermark is reached. |
| 2561 | * |
| 2562 | * Returns true if a fatal signal was delivered during throttling. If this |
| 2563 | * happens, the page allocator should not consider triggering the OOM killer. |
Mel Gorman | 5515061 | 2012-07-31 16:44:35 -0700 | [diff] [blame] | 2564 | */ |
Mel Gorman | 50694c2 | 2012-11-26 16:29:48 -0800 | [diff] [blame] | 2565 | static bool throttle_direct_reclaim(gfp_t gfp_mask, struct zonelist *zonelist, |
Mel Gorman | 5515061 | 2012-07-31 16:44:35 -0700 | [diff] [blame] | 2566 | nodemask_t *nodemask) |
| 2567 | { |
| 2568 | struct zone *zone; |
| 2569 | int high_zoneidx = gfp_zone(gfp_mask); |
| 2570 | pg_data_t *pgdat; |
| 2571 | |
| 2572 | /* |
| 2573 | * Kernel threads should not be throttled as they may be indirectly |
| 2574 | * responsible for cleaning pages necessary for reclaim to make forward |
| 2575 | * progress. kjournald for example may enter direct reclaim while |
| 2576 | * committing a transaction where throttling it could forcing other |
| 2577 | * processes to block on log_wait_commit(). |
| 2578 | */ |
| 2579 | if (current->flags & PF_KTHREAD) |
Mel Gorman | 50694c2 | 2012-11-26 16:29:48 -0800 | [diff] [blame] | 2580 | goto out; |
| 2581 | |
| 2582 | /* |
| 2583 | * If a fatal signal is pending, this process should not throttle. |
| 2584 | * It should return quickly so it can exit and free its memory |
| 2585 | */ |
| 2586 | if (fatal_signal_pending(current)) |
| 2587 | goto out; |
Mel Gorman | 5515061 | 2012-07-31 16:44:35 -0700 | [diff] [blame] | 2588 | |
| 2589 | /* Check if the pfmemalloc reserves are ok */ |
| 2590 | first_zones_zonelist(zonelist, high_zoneidx, NULL, &zone); |
| 2591 | pgdat = zone->zone_pgdat; |
| 2592 | if (pfmemalloc_watermark_ok(pgdat)) |
Mel Gorman | 50694c2 | 2012-11-26 16:29:48 -0800 | [diff] [blame] | 2593 | goto out; |
Mel Gorman | 5515061 | 2012-07-31 16:44:35 -0700 | [diff] [blame] | 2594 | |
Mel Gorman | 68243e7 | 2012-07-31 16:44:39 -0700 | [diff] [blame] | 2595 | /* Account for the throttling */ |
| 2596 | count_vm_event(PGSCAN_DIRECT_THROTTLE); |
| 2597 | |
Mel Gorman | 5515061 | 2012-07-31 16:44:35 -0700 | [diff] [blame] | 2598 | /* |
| 2599 | * If the caller cannot enter the filesystem, it's possible that it |
| 2600 | * is due to the caller holding an FS lock or performing a journal |
| 2601 | * transaction in the case of a filesystem like ext[3|4]. In this case, |
| 2602 | * it is not safe to block on pfmemalloc_wait as kswapd could be |
| 2603 | * blocked waiting on the same lock. Instead, throttle for up to a |
| 2604 | * second before continuing. |
| 2605 | */ |
| 2606 | if (!(gfp_mask & __GFP_FS)) { |
| 2607 | wait_event_interruptible_timeout(pgdat->pfmemalloc_wait, |
| 2608 | pfmemalloc_watermark_ok(pgdat), HZ); |
Mel Gorman | 50694c2 | 2012-11-26 16:29:48 -0800 | [diff] [blame] | 2609 | |
| 2610 | goto check_pending; |
Mel Gorman | 5515061 | 2012-07-31 16:44:35 -0700 | [diff] [blame] | 2611 | } |
| 2612 | |
| 2613 | /* Throttle until kswapd wakes the process */ |
| 2614 | wait_event_killable(zone->zone_pgdat->pfmemalloc_wait, |
| 2615 | pfmemalloc_watermark_ok(pgdat)); |
Mel Gorman | 50694c2 | 2012-11-26 16:29:48 -0800 | [diff] [blame] | 2616 | |
| 2617 | check_pending: |
| 2618 | if (fatal_signal_pending(current)) |
| 2619 | return true; |
| 2620 | |
| 2621 | out: |
| 2622 | return false; |
Mel Gorman | 5515061 | 2012-07-31 16:44:35 -0700 | [diff] [blame] | 2623 | } |
| 2624 | |
Mel Gorman | dac1d27 | 2008-04-28 02:12:12 -0700 | [diff] [blame] | 2625 | unsigned long try_to_free_pages(struct zonelist *zonelist, int order, |
KAMEZAWA Hiroyuki | 327c0e9 | 2009-03-31 15:23:31 -0700 | [diff] [blame] | 2626 | gfp_t gfp_mask, nodemask_t *nodemask) |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2627 | { |
Mel Gorman | 33906bc | 2010-08-09 17:19:16 -0700 | [diff] [blame] | 2628 | unsigned long nr_reclaimed; |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2629 | struct scan_control sc = { |
Ming Lei | 21caf2f | 2013-02-22 16:34:08 -0800 | [diff] [blame] | 2630 | .gfp_mask = (gfp_mask = memalloc_noio_flags(gfp_mask)), |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2631 | .may_writepage = !laptop_mode, |
KOSAKI Motohiro | 22fba33 | 2009-12-14 17:59:10 -0800 | [diff] [blame] | 2632 | .nr_to_reclaim = SWAP_CLUSTER_MAX, |
Johannes Weiner | a6dc60f8 | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 2633 | .may_unmap = 1, |
KOSAKI Motohiro | 2e2e425 | 2009-04-21 12:24:57 -0700 | [diff] [blame] | 2634 | .may_swap = 1, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2635 | .order = order, |
Konstantin Khlebnikov | 9e3b2f8 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 2636 | .priority = DEF_PRIORITY, |
Johannes Weiner | f16015f | 2012-01-12 17:17:52 -0800 | [diff] [blame] | 2637 | .target_mem_cgroup = NULL, |
KAMEZAWA Hiroyuki | 327c0e9 | 2009-03-31 15:23:31 -0700 | [diff] [blame] | 2638 | .nodemask = nodemask, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2639 | }; |
| 2640 | |
Mel Gorman | 5515061 | 2012-07-31 16:44:35 -0700 | [diff] [blame] | 2641 | /* |
Mel Gorman | 50694c2 | 2012-11-26 16:29:48 -0800 | [diff] [blame] | 2642 | * Do not enter reclaim if fatal signal was delivered while throttled. |
| 2643 | * 1 is returned so that the page allocator does not OOM kill at this |
| 2644 | * point. |
Mel Gorman | 5515061 | 2012-07-31 16:44:35 -0700 | [diff] [blame] | 2645 | */ |
Mel Gorman | 50694c2 | 2012-11-26 16:29:48 -0800 | [diff] [blame] | 2646 | if (throttle_direct_reclaim(gfp_mask, zonelist, nodemask)) |
Mel Gorman | 5515061 | 2012-07-31 16:44:35 -0700 | [diff] [blame] | 2647 | return 1; |
| 2648 | |
Mel Gorman | 33906bc | 2010-08-09 17:19:16 -0700 | [diff] [blame] | 2649 | trace_mm_vmscan_direct_reclaim_begin(order, |
| 2650 | sc.may_writepage, |
| 2651 | gfp_mask); |
| 2652 | |
Vladimir Davydov | 3115cd9 | 2014-04-03 14:47:22 -0700 | [diff] [blame] | 2653 | nr_reclaimed = do_try_to_free_pages(zonelist, &sc); |
Mel Gorman | 33906bc | 2010-08-09 17:19:16 -0700 | [diff] [blame] | 2654 | |
| 2655 | trace_mm_vmscan_direct_reclaim_end(nr_reclaimed); |
| 2656 | |
| 2657 | return nr_reclaimed; |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2658 | } |
| 2659 | |
Andrew Morton | c255a45 | 2012-07-31 16:43:02 -0700 | [diff] [blame] | 2660 | #ifdef CONFIG_MEMCG |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2661 | |
Johannes Weiner | 72835c8 | 2012-01-12 17:18:32 -0800 | [diff] [blame] | 2662 | unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *memcg, |
Balbir Singh | 4e41695 | 2009-09-23 15:56:39 -0700 | [diff] [blame] | 2663 | gfp_t gfp_mask, bool noswap, |
Ying Han | 0ae5e89 | 2011-05-26 16:25:25 -0700 | [diff] [blame] | 2664 | struct zone *zone, |
| 2665 | unsigned long *nr_scanned) |
Balbir Singh | 4e41695 | 2009-09-23 15:56:39 -0700 | [diff] [blame] | 2666 | { |
| 2667 | struct scan_control sc = { |
Ying Han | 0ae5e89 | 2011-05-26 16:25:25 -0700 | [diff] [blame] | 2668 | .nr_scanned = 0, |
KOSAKI Motohiro | b8f5c56 | 2010-08-10 18:03:02 -0700 | [diff] [blame] | 2669 | .nr_to_reclaim = SWAP_CLUSTER_MAX, |
Balbir Singh | 4e41695 | 2009-09-23 15:56:39 -0700 | [diff] [blame] | 2670 | .may_writepage = !laptop_mode, |
| 2671 | .may_unmap = 1, |
| 2672 | .may_swap = !noswap, |
Balbir Singh | 4e41695 | 2009-09-23 15:56:39 -0700 | [diff] [blame] | 2673 | .order = 0, |
Konstantin Khlebnikov | 9e3b2f8 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 2674 | .priority = 0, |
Johannes Weiner | 72835c8 | 2012-01-12 17:18:32 -0800 | [diff] [blame] | 2675 | .target_mem_cgroup = memcg, |
Balbir Singh | 4e41695 | 2009-09-23 15:56:39 -0700 | [diff] [blame] | 2676 | }; |
Konstantin Khlebnikov | f9be23d | 2012-05-29 15:07:02 -0700 | [diff] [blame] | 2677 | struct lruvec *lruvec = mem_cgroup_zone_lruvec(zone, memcg); |
Ying Han | 0ae5e89 | 2011-05-26 16:25:25 -0700 | [diff] [blame] | 2678 | |
Balbir Singh | 4e41695 | 2009-09-23 15:56:39 -0700 | [diff] [blame] | 2679 | sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) | |
| 2680 | (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK); |
KOSAKI Motohiro | bdce6d9 | 2010-08-09 17:19:56 -0700 | [diff] [blame] | 2681 | |
Konstantin Khlebnikov | 9e3b2f8 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 2682 | trace_mm_vmscan_memcg_softlimit_reclaim_begin(sc.order, |
KOSAKI Motohiro | bdce6d9 | 2010-08-09 17:19:56 -0700 | [diff] [blame] | 2683 | sc.may_writepage, |
| 2684 | sc.gfp_mask); |
| 2685 | |
Balbir Singh | 4e41695 | 2009-09-23 15:56:39 -0700 | [diff] [blame] | 2686 | /* |
| 2687 | * NOTE: Although we can get the priority field, using it |
| 2688 | * here is not a good idea, since it limits the pages we can scan. |
| 2689 | * if we don't reclaim here, the shrink_zone from balance_pgdat |
| 2690 | * will pick up pages from other mem cgroup's as well. We hack |
| 2691 | * the priority and make it zero. |
| 2692 | */ |
Konstantin Khlebnikov | f9be23d | 2012-05-29 15:07:02 -0700 | [diff] [blame] | 2693 | shrink_lruvec(lruvec, &sc); |
KOSAKI Motohiro | bdce6d9 | 2010-08-09 17:19:56 -0700 | [diff] [blame] | 2694 | |
| 2695 | trace_mm_vmscan_memcg_softlimit_reclaim_end(sc.nr_reclaimed); |
| 2696 | |
Ying Han | 0ae5e89 | 2011-05-26 16:25:25 -0700 | [diff] [blame] | 2697 | *nr_scanned = sc.nr_scanned; |
Balbir Singh | 4e41695 | 2009-09-23 15:56:39 -0700 | [diff] [blame] | 2698 | return sc.nr_reclaimed; |
| 2699 | } |
| 2700 | |
Johannes Weiner | 72835c8 | 2012-01-12 17:18:32 -0800 | [diff] [blame] | 2701 | unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg, |
KOSAKI Motohiro | a7885eb | 2009-01-07 18:08:24 -0800 | [diff] [blame] | 2702 | gfp_t gfp_mask, |
Johannes Weiner | 185efc0 | 2011-09-14 16:21:58 -0700 | [diff] [blame] | 2703 | bool noswap) |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2704 | { |
Balbir Singh | 4e41695 | 2009-09-23 15:56:39 -0700 | [diff] [blame] | 2705 | struct zonelist *zonelist; |
KOSAKI Motohiro | bdce6d9 | 2010-08-09 17:19:56 -0700 | [diff] [blame] | 2706 | unsigned long nr_reclaimed; |
Ying Han | 889976d | 2011-05-26 16:25:33 -0700 | [diff] [blame] | 2707 | int nid; |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2708 | struct scan_control sc = { |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2709 | .may_writepage = !laptop_mode, |
Johannes Weiner | a6dc60f8 | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 2710 | .may_unmap = 1, |
KOSAKI Motohiro | 2e2e425 | 2009-04-21 12:24:57 -0700 | [diff] [blame] | 2711 | .may_swap = !noswap, |
KOSAKI Motohiro | 22fba33 | 2009-12-14 17:59:10 -0800 | [diff] [blame] | 2712 | .nr_to_reclaim = SWAP_CLUSTER_MAX, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2713 | .order = 0, |
Konstantin Khlebnikov | 9e3b2f8 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 2714 | .priority = DEF_PRIORITY, |
Johannes Weiner | 72835c8 | 2012-01-12 17:18:32 -0800 | [diff] [blame] | 2715 | .target_mem_cgroup = memcg, |
KAMEZAWA Hiroyuki | 327c0e9 | 2009-03-31 15:23:31 -0700 | [diff] [blame] | 2716 | .nodemask = NULL, /* we don't care the placement */ |
Ying Han | a09ed5e | 2011-05-24 17:12:26 -0700 | [diff] [blame] | 2717 | .gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) | |
| 2718 | (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK), |
| 2719 | }; |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2720 | |
Ying Han | 889976d | 2011-05-26 16:25:33 -0700 | [diff] [blame] | 2721 | /* |
| 2722 | * Unlike direct reclaim via alloc_pages(), memcg's reclaim doesn't |
| 2723 | * take care of from where we get pages. So the node where we start the |
| 2724 | * scan does not need to be the current node. |
| 2725 | */ |
Johannes Weiner | 72835c8 | 2012-01-12 17:18:32 -0800 | [diff] [blame] | 2726 | nid = mem_cgroup_select_victim_node(memcg); |
Ying Han | 889976d | 2011-05-26 16:25:33 -0700 | [diff] [blame] | 2727 | |
| 2728 | zonelist = NODE_DATA(nid)->node_zonelists; |
KOSAKI Motohiro | bdce6d9 | 2010-08-09 17:19:56 -0700 | [diff] [blame] | 2729 | |
| 2730 | trace_mm_vmscan_memcg_reclaim_begin(0, |
| 2731 | sc.may_writepage, |
| 2732 | sc.gfp_mask); |
| 2733 | |
Vladimir Davydov | 3115cd9 | 2014-04-03 14:47:22 -0700 | [diff] [blame] | 2734 | nr_reclaimed = do_try_to_free_pages(zonelist, &sc); |
KOSAKI Motohiro | bdce6d9 | 2010-08-09 17:19:56 -0700 | [diff] [blame] | 2735 | |
| 2736 | trace_mm_vmscan_memcg_reclaim_end(nr_reclaimed); |
| 2737 | |
| 2738 | return nr_reclaimed; |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2739 | } |
| 2740 | #endif |
| 2741 | |
Konstantin Khlebnikov | 9e3b2f8 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 2742 | static void age_active_anon(struct zone *zone, struct scan_control *sc) |
Johannes Weiner | f16015f | 2012-01-12 17:17:52 -0800 | [diff] [blame] | 2743 | { |
Johannes Weiner | b95a2f2 | 2012-01-12 17:18:06 -0800 | [diff] [blame] | 2744 | struct mem_cgroup *memcg; |
Johannes Weiner | f16015f | 2012-01-12 17:17:52 -0800 | [diff] [blame] | 2745 | |
Johannes Weiner | b95a2f2 | 2012-01-12 17:18:06 -0800 | [diff] [blame] | 2746 | if (!total_swap_pages) |
| 2747 | return; |
| 2748 | |
| 2749 | memcg = mem_cgroup_iter(NULL, NULL, NULL); |
| 2750 | do { |
Konstantin Khlebnikov | c56d5c7 | 2012-05-29 15:07:00 -0700 | [diff] [blame] | 2751 | struct lruvec *lruvec = mem_cgroup_zone_lruvec(zone, memcg); |
Johannes Weiner | b95a2f2 | 2012-01-12 17:18:06 -0800 | [diff] [blame] | 2752 | |
Konstantin Khlebnikov | c56d5c7 | 2012-05-29 15:07:00 -0700 | [diff] [blame] | 2753 | if (inactive_anon_is_low(lruvec)) |
Konstantin Khlebnikov | 1a93be0 | 2012-05-29 15:07:01 -0700 | [diff] [blame] | 2754 | shrink_active_list(SWAP_CLUSTER_MAX, lruvec, |
Konstantin Khlebnikov | 9e3b2f8 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 2755 | sc, LRU_ACTIVE_ANON); |
Johannes Weiner | b95a2f2 | 2012-01-12 17:18:06 -0800 | [diff] [blame] | 2756 | |
| 2757 | memcg = mem_cgroup_iter(NULL, memcg, NULL); |
| 2758 | } while (memcg); |
Johannes Weiner | f16015f | 2012-01-12 17:17:52 -0800 | [diff] [blame] | 2759 | } |
| 2760 | |
Johannes Weiner | 60cefed | 2012-11-29 13:54:23 -0800 | [diff] [blame] | 2761 | static bool zone_balanced(struct zone *zone, int order, |
| 2762 | unsigned long balance_gap, int classzone_idx) |
| 2763 | { |
| 2764 | if (!zone_watermark_ok_safe(zone, order, high_wmark_pages(zone) + |
| 2765 | balance_gap, classzone_idx, 0)) |
| 2766 | return false; |
| 2767 | |
Kirill A. Shutemov | d84da3f | 2012-12-11 16:00:31 -0800 | [diff] [blame] | 2768 | if (IS_ENABLED(CONFIG_COMPACTION) && order && |
| 2769 | !compaction_suitable(zone, order)) |
Johannes Weiner | 60cefed | 2012-11-29 13:54:23 -0800 | [diff] [blame] | 2770 | return false; |
| 2771 | |
| 2772 | return true; |
| 2773 | } |
| 2774 | |
Mel Gorman | 1741c87 | 2011-01-13 15:46:21 -0800 | [diff] [blame] | 2775 | /* |
Zlatko Calusic | 4ae0a48 | 2012-12-23 15:12:54 +0100 | [diff] [blame] | 2776 | * pgdat_balanced() is used when checking if a node is balanced. |
| 2777 | * |
| 2778 | * For order-0, all zones must be balanced! |
| 2779 | * |
| 2780 | * For high-order allocations only zones that meet watermarks and are in a |
| 2781 | * zone allowed by the callers classzone_idx are added to balanced_pages. The |
| 2782 | * total of balanced pages must be at least 25% of the zones allowed by |
| 2783 | * classzone_idx for the node to be considered balanced. Forcing all zones to |
| 2784 | * be balanced for high orders can cause excessive reclaim when there are |
| 2785 | * imbalanced zones. |
Mel Gorman | 1741c87 | 2011-01-13 15:46:21 -0800 | [diff] [blame] | 2786 | * The choice of 25% is due to |
| 2787 | * o a 16M DMA zone that is balanced will not balance a zone on any |
| 2788 | * reasonable sized machine |
| 2789 | * o On all other machines, the top zone must be at least a reasonable |
Lucas De Marchi | 25985ed | 2011-03-30 22:57:33 -0300 | [diff] [blame] | 2790 | * percentage of the middle zones. For example, on 32-bit x86, highmem |
Mel Gorman | 1741c87 | 2011-01-13 15:46:21 -0800 | [diff] [blame] | 2791 | * would need to be at least 256M for it to be balance a whole node. |
| 2792 | * Similarly, on x86-64 the Normal zone would need to be at least 1G |
| 2793 | * to balance a node on its own. These seemed like reasonable ratios. |
| 2794 | */ |
Zlatko Calusic | 4ae0a48 | 2012-12-23 15:12:54 +0100 | [diff] [blame] | 2795 | static bool pgdat_balanced(pg_data_t *pgdat, int order, int classzone_idx) |
Mel Gorman | 1741c87 | 2011-01-13 15:46:21 -0800 | [diff] [blame] | 2796 | { |
Jiang Liu | b40da04 | 2013-02-22 16:33:52 -0800 | [diff] [blame] | 2797 | unsigned long managed_pages = 0; |
Zlatko Calusic | 4ae0a48 | 2012-12-23 15:12:54 +0100 | [diff] [blame] | 2798 | unsigned long balanced_pages = 0; |
Mel Gorman | 1741c87 | 2011-01-13 15:46:21 -0800 | [diff] [blame] | 2799 | int i; |
| 2800 | |
Zlatko Calusic | 4ae0a48 | 2012-12-23 15:12:54 +0100 | [diff] [blame] | 2801 | /* Check the watermark levels */ |
| 2802 | for (i = 0; i <= classzone_idx; i++) { |
| 2803 | struct zone *zone = pgdat->node_zones + i; |
Mel Gorman | 1741c87 | 2011-01-13 15:46:21 -0800 | [diff] [blame] | 2804 | |
Zlatko Calusic | 4ae0a48 | 2012-12-23 15:12:54 +0100 | [diff] [blame] | 2805 | if (!populated_zone(zone)) |
| 2806 | continue; |
| 2807 | |
Jiang Liu | b40da04 | 2013-02-22 16:33:52 -0800 | [diff] [blame] | 2808 | managed_pages += zone->managed_pages; |
Zlatko Calusic | 4ae0a48 | 2012-12-23 15:12:54 +0100 | [diff] [blame] | 2809 | |
| 2810 | /* |
| 2811 | * A special case here: |
| 2812 | * |
| 2813 | * balance_pgdat() skips over all_unreclaimable after |
| 2814 | * DEF_PRIORITY. Effectively, it considers them balanced so |
| 2815 | * they must be considered balanced here as well! |
| 2816 | */ |
Lisa Du | 6e543d5 | 2013-09-11 14:22:36 -0700 | [diff] [blame] | 2817 | if (!zone_reclaimable(zone)) { |
Jiang Liu | b40da04 | 2013-02-22 16:33:52 -0800 | [diff] [blame] | 2818 | balanced_pages += zone->managed_pages; |
Zlatko Calusic | 4ae0a48 | 2012-12-23 15:12:54 +0100 | [diff] [blame] | 2819 | continue; |
| 2820 | } |
| 2821 | |
| 2822 | if (zone_balanced(zone, order, 0, i)) |
Jiang Liu | b40da04 | 2013-02-22 16:33:52 -0800 | [diff] [blame] | 2823 | balanced_pages += zone->managed_pages; |
Zlatko Calusic | 4ae0a48 | 2012-12-23 15:12:54 +0100 | [diff] [blame] | 2824 | else if (!order) |
| 2825 | return false; |
| 2826 | } |
| 2827 | |
| 2828 | if (order) |
Jiang Liu | b40da04 | 2013-02-22 16:33:52 -0800 | [diff] [blame] | 2829 | return balanced_pages >= (managed_pages >> 2); |
Zlatko Calusic | 4ae0a48 | 2012-12-23 15:12:54 +0100 | [diff] [blame] | 2830 | else |
| 2831 | return true; |
Mel Gorman | 1741c87 | 2011-01-13 15:46:21 -0800 | [diff] [blame] | 2832 | } |
| 2833 | |
Mel Gorman | 5515061 | 2012-07-31 16:44:35 -0700 | [diff] [blame] | 2834 | /* |
| 2835 | * Prepare kswapd for sleeping. This verifies that there are no processes |
| 2836 | * waiting in throttle_direct_reclaim() and that watermarks have been met. |
| 2837 | * |
| 2838 | * Returns true if kswapd is ready to sleep |
| 2839 | */ |
| 2840 | static bool prepare_kswapd_sleep(pg_data_t *pgdat, int order, long remaining, |
Mel Gorman | dc83edd | 2011-01-13 15:46:26 -0800 | [diff] [blame] | 2841 | int classzone_idx) |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 2842 | { |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 2843 | /* If a direct reclaimer woke kswapd within HZ/10, it's premature */ |
| 2844 | if (remaining) |
Mel Gorman | 5515061 | 2012-07-31 16:44:35 -0700 | [diff] [blame] | 2845 | return false; |
| 2846 | |
| 2847 | /* |
| 2848 | * There is a potential race between when kswapd checks its watermarks |
| 2849 | * and a process gets throttled. There is also a potential race if |
| 2850 | * processes get throttled, kswapd wakes, a large process exits therby |
| 2851 | * balancing the zones that causes kswapd to miss a wakeup. If kswapd |
| 2852 | * is going to sleep, no process should be sleeping on pfmemalloc_wait |
| 2853 | * so wake them now if necessary. If necessary, processes will wake |
| 2854 | * kswapd and get throttled again |
| 2855 | */ |
| 2856 | if (waitqueue_active(&pgdat->pfmemalloc_wait)) { |
| 2857 | wake_up(&pgdat->pfmemalloc_wait); |
| 2858 | return false; |
| 2859 | } |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 2860 | |
Zlatko Calusic | 4ae0a48 | 2012-12-23 15:12:54 +0100 | [diff] [blame] | 2861 | return pgdat_balanced(pgdat, order, classzone_idx); |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 2862 | } |
| 2863 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2864 | /* |
Mel Gorman | 7548536 | 2013-07-03 15:01:42 -0700 | [diff] [blame] | 2865 | * kswapd shrinks the zone by the number of pages required to reach |
| 2866 | * the high watermark. |
Mel Gorman | b8e83b9 | 2013-07-03 15:01:45 -0700 | [diff] [blame] | 2867 | * |
| 2868 | * Returns true if kswapd scanned at least the requested number of pages to |
Mel Gorman | 283aba9 | 2013-07-03 15:01:51 -0700 | [diff] [blame] | 2869 | * reclaim or if the lack of progress was due to pages under writeback. |
| 2870 | * This is used to determine if the scanning priority needs to be raised. |
Mel Gorman | 7548536 | 2013-07-03 15:01:42 -0700 | [diff] [blame] | 2871 | */ |
Mel Gorman | b8e83b9 | 2013-07-03 15:01:45 -0700 | [diff] [blame] | 2872 | static bool kswapd_shrink_zone(struct zone *zone, |
Mel Gorman | 7c954f6 | 2013-07-03 15:01:54 -0700 | [diff] [blame] | 2873 | int classzone_idx, |
Mel Gorman | 7548536 | 2013-07-03 15:01:42 -0700 | [diff] [blame] | 2874 | struct scan_control *sc, |
Mel Gorman | 2ab44f4 | 2013-07-03 15:01:47 -0700 | [diff] [blame] | 2875 | unsigned long lru_pages, |
| 2876 | unsigned long *nr_attempted) |
Mel Gorman | 7548536 | 2013-07-03 15:01:42 -0700 | [diff] [blame] | 2877 | { |
Mel Gorman | 7c954f6 | 2013-07-03 15:01:54 -0700 | [diff] [blame] | 2878 | int testorder = sc->order; |
| 2879 | unsigned long balance_gap; |
Mel Gorman | 7548536 | 2013-07-03 15:01:42 -0700 | [diff] [blame] | 2880 | struct reclaim_state *reclaim_state = current->reclaim_state; |
| 2881 | struct shrink_control shrink = { |
| 2882 | .gfp_mask = sc->gfp_mask, |
| 2883 | }; |
Mel Gorman | 7c954f6 | 2013-07-03 15:01:54 -0700 | [diff] [blame] | 2884 | bool lowmem_pressure; |
Mel Gorman | 7548536 | 2013-07-03 15:01:42 -0700 | [diff] [blame] | 2885 | |
| 2886 | /* Reclaim above the high watermark. */ |
| 2887 | sc->nr_to_reclaim = max(SWAP_CLUSTER_MAX, high_wmark_pages(zone)); |
Mel Gorman | 7c954f6 | 2013-07-03 15:01:54 -0700 | [diff] [blame] | 2888 | |
| 2889 | /* |
| 2890 | * Kswapd reclaims only single pages with compaction enabled. Trying |
| 2891 | * too hard to reclaim until contiguous free pages have become |
| 2892 | * available can hurt performance by evicting too much useful data |
| 2893 | * from memory. Do not reclaim more than needed for compaction. |
| 2894 | */ |
| 2895 | if (IS_ENABLED(CONFIG_COMPACTION) && sc->order && |
| 2896 | compaction_suitable(zone, sc->order) != |
| 2897 | COMPACT_SKIPPED) |
| 2898 | testorder = 0; |
| 2899 | |
| 2900 | /* |
| 2901 | * We put equal pressure on every zone, unless one zone has way too |
| 2902 | * many pages free already. The "too many pages" is defined as the |
| 2903 | * high wmark plus a "gap" where the gap is either the low |
| 2904 | * watermark or 1% of the zone, whichever is smaller. |
| 2905 | */ |
| 2906 | balance_gap = min(low_wmark_pages(zone), |
| 2907 | (zone->managed_pages + KSWAPD_ZONE_BALANCE_GAP_RATIO-1) / |
| 2908 | KSWAPD_ZONE_BALANCE_GAP_RATIO); |
| 2909 | |
| 2910 | /* |
| 2911 | * If there is no low memory pressure or the zone is balanced then no |
| 2912 | * reclaim is necessary |
| 2913 | */ |
| 2914 | lowmem_pressure = (buffer_heads_over_limit && is_highmem(zone)); |
| 2915 | if (!lowmem_pressure && zone_balanced(zone, testorder, |
| 2916 | balance_gap, classzone_idx)) |
| 2917 | return true; |
| 2918 | |
Mel Gorman | 7548536 | 2013-07-03 15:01:42 -0700 | [diff] [blame] | 2919 | shrink_zone(zone, sc); |
Dave Chinner | 0ce3d74 | 2013-08-28 10:18:03 +1000 | [diff] [blame] | 2920 | nodes_clear(shrink.nodes_to_scan); |
| 2921 | node_set(zone_to_nid(zone), shrink.nodes_to_scan); |
Mel Gorman | 7548536 | 2013-07-03 15:01:42 -0700 | [diff] [blame] | 2922 | |
| 2923 | reclaim_state->reclaimed_slab = 0; |
Lisa Du | 6e543d5 | 2013-09-11 14:22:36 -0700 | [diff] [blame] | 2924 | shrink_slab(&shrink, sc->nr_scanned, lru_pages); |
Mel Gorman | 7548536 | 2013-07-03 15:01:42 -0700 | [diff] [blame] | 2925 | sc->nr_reclaimed += reclaim_state->reclaimed_slab; |
| 2926 | |
Mel Gorman | 2ab44f4 | 2013-07-03 15:01:47 -0700 | [diff] [blame] | 2927 | /* Account for the number of pages attempted to reclaim */ |
| 2928 | *nr_attempted += sc->nr_to_reclaim; |
| 2929 | |
Mel Gorman | 283aba9 | 2013-07-03 15:01:51 -0700 | [diff] [blame] | 2930 | zone_clear_flag(zone, ZONE_WRITEBACK); |
| 2931 | |
Mel Gorman | 7c954f6 | 2013-07-03 15:01:54 -0700 | [diff] [blame] | 2932 | /* |
| 2933 | * If a zone reaches its high watermark, consider it to be no longer |
| 2934 | * congested. It's possible there are dirty pages backed by congested |
| 2935 | * BDIs but as pressure is relieved, speculatively avoid congestion |
| 2936 | * waits. |
| 2937 | */ |
Lisa Du | 6e543d5 | 2013-09-11 14:22:36 -0700 | [diff] [blame] | 2938 | if (zone_reclaimable(zone) && |
Mel Gorman | 7c954f6 | 2013-07-03 15:01:54 -0700 | [diff] [blame] | 2939 | zone_balanced(zone, testorder, 0, classzone_idx)) { |
| 2940 | zone_clear_flag(zone, ZONE_CONGESTED); |
| 2941 | zone_clear_flag(zone, ZONE_TAIL_LRU_DIRTY); |
| 2942 | } |
| 2943 | |
Mel Gorman | b8e83b9 | 2013-07-03 15:01:45 -0700 | [diff] [blame] | 2944 | return sc->nr_scanned >= sc->nr_to_reclaim; |
Mel Gorman | 7548536 | 2013-07-03 15:01:42 -0700 | [diff] [blame] | 2945 | } |
| 2946 | |
| 2947 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2948 | * For kswapd, balance_pgdat() will work across all this node's zones until |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 2949 | * they are all at high_wmark_pages(zone). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2950 | * |
Mel Gorman | 0abdee2 | 2011-01-13 15:46:22 -0800 | [diff] [blame] | 2951 | * Returns the final order kswapd was reclaiming at |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2952 | * |
| 2953 | * There is special handling here for zones which are full of pinned pages. |
| 2954 | * This can happen if the pages are all mlocked, or if they are all used by |
| 2955 | * device drivers (say, ZONE_DMA). Or if they are all in use by hugetlb. |
| 2956 | * What we do is to detect the case where all pages in the zone have been |
| 2957 | * scanned twice and there has been zero successful reclaim. Mark the zone as |
| 2958 | * dead and from now on, only perform a short scan. Basically we're polling |
| 2959 | * the zone for when the problem goes away. |
| 2960 | * |
| 2961 | * kswapd scans the zones in the highmem->normal->dma direction. It skips |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 2962 | * zones which have free_pages > high_wmark_pages(zone), but once a zone is |
| 2963 | * found to have free_pages <= high_wmark_pages(zone), we scan that zone and the |
| 2964 | * lower zones regardless of the number of free pages in the lower zones. This |
| 2965 | * interoperates with the page allocator fallback scheme to ensure that aging |
| 2966 | * of pages is balanced across the zones. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2967 | */ |
Mel Gorman | 9950474 | 2011-01-13 15:46:20 -0800 | [diff] [blame] | 2968 | static unsigned long balance_pgdat(pg_data_t *pgdat, int order, |
Mel Gorman | dc83edd | 2011-01-13 15:46:26 -0800 | [diff] [blame] | 2969 | int *classzone_idx) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2970 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2971 | int i; |
Mel Gorman | 9950474 | 2011-01-13 15:46:20 -0800 | [diff] [blame] | 2972 | int end_zone = 0; /* Inclusive. 0 = ZONE_DMA */ |
Andrew Morton | 0608f43 | 2013-09-24 15:27:41 -0700 | [diff] [blame] | 2973 | unsigned long nr_soft_reclaimed; |
| 2974 | unsigned long nr_soft_scanned; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2975 | struct scan_control sc = { |
| 2976 | .gfp_mask = GFP_KERNEL, |
Mel Gorman | b8e83b9 | 2013-07-03 15:01:45 -0700 | [diff] [blame] | 2977 | .priority = DEF_PRIORITY, |
Johannes Weiner | a6dc60f8 | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 2978 | .may_unmap = 1, |
KOSAKI Motohiro | 2e2e425 | 2009-04-21 12:24:57 -0700 | [diff] [blame] | 2979 | .may_swap = 1, |
Mel Gorman | b8e83b9 | 2013-07-03 15:01:45 -0700 | [diff] [blame] | 2980 | .may_writepage = !laptop_mode, |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 2981 | .order = order, |
Johannes Weiner | f16015f | 2012-01-12 17:17:52 -0800 | [diff] [blame] | 2982 | .target_mem_cgroup = NULL, |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2983 | }; |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 2984 | count_vm_event(PAGEOUTRUN); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2985 | |
Konstantin Khlebnikov | 9e3b2f8 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 2986 | do { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2987 | unsigned long lru_pages = 0; |
Mel Gorman | 2ab44f4 | 2013-07-03 15:01:47 -0700 | [diff] [blame] | 2988 | unsigned long nr_attempted = 0; |
Mel Gorman | b8e83b9 | 2013-07-03 15:01:45 -0700 | [diff] [blame] | 2989 | bool raise_priority = true; |
Mel Gorman | 2ab44f4 | 2013-07-03 15:01:47 -0700 | [diff] [blame] | 2990 | bool pgdat_needs_compaction = (order > 0); |
Mel Gorman | b8e83b9 | 2013-07-03 15:01:45 -0700 | [diff] [blame] | 2991 | |
| 2992 | sc.nr_reclaimed = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2993 | |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2994 | /* |
| 2995 | * Scan in the highmem->dma direction for the highest |
| 2996 | * zone which needs scanning |
| 2997 | */ |
| 2998 | for (i = pgdat->nr_zones - 1; i >= 0; i--) { |
| 2999 | struct zone *zone = pgdat->node_zones + i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3000 | |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 3001 | if (!populated_zone(zone)) |
| 3002 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3003 | |
Lisa Du | 6e543d5 | 2013-09-11 14:22:36 -0700 | [diff] [blame] | 3004 | if (sc.priority != DEF_PRIORITY && |
| 3005 | !zone_reclaimable(zone)) |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 3006 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3007 | |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 3008 | /* |
| 3009 | * Do some background aging of the anon list, to give |
| 3010 | * pages a chance to be referenced before reclaiming. |
| 3011 | */ |
Konstantin Khlebnikov | 9e3b2f8 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 3012 | age_active_anon(zone, &sc); |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 3013 | |
Mel Gorman | cc715d9 | 2012-03-21 16:34:00 -0700 | [diff] [blame] | 3014 | /* |
| 3015 | * If the number of buffer_heads in the machine |
| 3016 | * exceeds the maximum allowed level and this node |
| 3017 | * has a highmem zone, force kswapd to reclaim from |
| 3018 | * it to relieve lowmem pressure. |
| 3019 | */ |
| 3020 | if (buffer_heads_over_limit && is_highmem_idx(i)) { |
| 3021 | end_zone = i; |
| 3022 | break; |
| 3023 | } |
| 3024 | |
Johannes Weiner | 60cefed | 2012-11-29 13:54:23 -0800 | [diff] [blame] | 3025 | if (!zone_balanced(zone, order, 0, 0)) { |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 3026 | end_zone = i; |
Andrew Morton | e1dbeda | 2006-12-06 20:32:01 -0800 | [diff] [blame] | 3027 | break; |
Shaohua Li | 439423f | 2011-08-25 15:59:12 -0700 | [diff] [blame] | 3028 | } else { |
Mel Gorman | d43006d | 2013-07-03 15:01:50 -0700 | [diff] [blame] | 3029 | /* |
| 3030 | * If balanced, clear the dirty and congested |
| 3031 | * flags |
| 3032 | */ |
Shaohua Li | 439423f | 2011-08-25 15:59:12 -0700 | [diff] [blame] | 3033 | zone_clear_flag(zone, ZONE_CONGESTED); |
Mel Gorman | d43006d | 2013-07-03 15:01:50 -0700 | [diff] [blame] | 3034 | zone_clear_flag(zone, ZONE_TAIL_LRU_DIRTY); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3035 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3036 | } |
Zlatko Calusic | dafcb73 | 2013-02-22 16:32:34 -0800 | [diff] [blame] | 3037 | |
Mel Gorman | b8e83b9 | 2013-07-03 15:01:45 -0700 | [diff] [blame] | 3038 | if (i < 0) |
Andrew Morton | e1dbeda | 2006-12-06 20:32:01 -0800 | [diff] [blame] | 3039 | goto out; |
| 3040 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3041 | for (i = 0; i <= end_zone; i++) { |
| 3042 | struct zone *zone = pgdat->node_zones + i; |
| 3043 | |
Mel Gorman | 2ab44f4 | 2013-07-03 15:01:47 -0700 | [diff] [blame] | 3044 | if (!populated_zone(zone)) |
| 3045 | continue; |
| 3046 | |
Wu Fengguang | adea02a | 2009-09-21 17:01:42 -0700 | [diff] [blame] | 3047 | lru_pages += zone_reclaimable_pages(zone); |
Mel Gorman | 2ab44f4 | 2013-07-03 15:01:47 -0700 | [diff] [blame] | 3048 | |
| 3049 | /* |
| 3050 | * If any zone is currently balanced then kswapd will |
| 3051 | * not call compaction as it is expected that the |
| 3052 | * necessary pages are already available. |
| 3053 | */ |
| 3054 | if (pgdat_needs_compaction && |
| 3055 | zone_watermark_ok(zone, order, |
| 3056 | low_wmark_pages(zone), |
| 3057 | *classzone_idx, 0)) |
| 3058 | pgdat_needs_compaction = false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3059 | } |
| 3060 | |
| 3061 | /* |
Mel Gorman | b7ea3c4 | 2013-07-03 15:01:53 -0700 | [diff] [blame] | 3062 | * If we're getting trouble reclaiming, start doing writepage |
| 3063 | * even in laptop mode. |
| 3064 | */ |
| 3065 | if (sc.priority < DEF_PRIORITY - 2) |
| 3066 | sc.may_writepage = 1; |
| 3067 | |
| 3068 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3069 | * Now scan the zone in the dma->highmem direction, stopping |
| 3070 | * at the last zone which needs scanning. |
| 3071 | * |
| 3072 | * We do this because the page allocator works in the opposite |
| 3073 | * direction. This prevents the page allocator from allocating |
| 3074 | * pages behind kswapd's direction of progress, which would |
| 3075 | * cause too much scanning of the lower zones. |
| 3076 | */ |
| 3077 | for (i = 0; i <= end_zone; i++) { |
| 3078 | struct zone *zone = pgdat->node_zones + i; |
| 3079 | |
Con Kolivas | f3fe651 | 2006-01-06 00:11:15 -0800 | [diff] [blame] | 3080 | if (!populated_zone(zone)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3081 | continue; |
| 3082 | |
Lisa Du | 6e543d5 | 2013-09-11 14:22:36 -0700 | [diff] [blame] | 3083 | if (sc.priority != DEF_PRIORITY && |
| 3084 | !zone_reclaimable(zone)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3085 | continue; |
| 3086 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3087 | sc.nr_scanned = 0; |
Balbir Singh | 4e41695 | 2009-09-23 15:56:39 -0700 | [diff] [blame] | 3088 | |
Andrew Morton | 0608f43 | 2013-09-24 15:27:41 -0700 | [diff] [blame] | 3089 | nr_soft_scanned = 0; |
| 3090 | /* |
| 3091 | * Call soft limit reclaim before calling shrink_zone. |
| 3092 | */ |
| 3093 | nr_soft_reclaimed = mem_cgroup_soft_limit_reclaim(zone, |
| 3094 | order, sc.gfp_mask, |
| 3095 | &nr_soft_scanned); |
| 3096 | sc.nr_reclaimed += nr_soft_reclaimed; |
| 3097 | |
Rik van Riel | 32a4330 | 2007-10-16 01:24:50 -0700 | [diff] [blame] | 3098 | /* |
Mel Gorman | 7c954f6 | 2013-07-03 15:01:54 -0700 | [diff] [blame] | 3099 | * There should be no need to raise the scanning |
| 3100 | * priority if enough pages are already being scanned |
| 3101 | * that that high watermark would be met at 100% |
| 3102 | * efficiency. |
Rik van Riel | 32a4330 | 2007-10-16 01:24:50 -0700 | [diff] [blame] | 3103 | */ |
Mel Gorman | 7c954f6 | 2013-07-03 15:01:54 -0700 | [diff] [blame] | 3104 | if (kswapd_shrink_zone(zone, end_zone, &sc, |
| 3105 | lru_pages, &nr_attempted)) |
| 3106 | raise_priority = false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3107 | } |
Mel Gorman | 5515061 | 2012-07-31 16:44:35 -0700 | [diff] [blame] | 3108 | |
| 3109 | /* |
| 3110 | * If the low watermark is met there is no need for processes |
| 3111 | * to be throttled on pfmemalloc_wait as they should not be |
| 3112 | * able to safely make forward progress. Wake them |
| 3113 | */ |
| 3114 | if (waitqueue_active(&pgdat->pfmemalloc_wait) && |
| 3115 | pfmemalloc_watermark_ok(pgdat)) |
| 3116 | wake_up(&pgdat->pfmemalloc_wait); |
| 3117 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3118 | /* |
Mel Gorman | b8e83b9 | 2013-07-03 15:01:45 -0700 | [diff] [blame] | 3119 | * Fragmentation may mean that the system cannot be rebalanced |
| 3120 | * for high-order allocations in all zones. If twice the |
| 3121 | * allocation size has been reclaimed and the zones are still |
| 3122 | * not balanced then recheck the watermarks at order-0 to |
| 3123 | * prevent kswapd reclaiming excessively. Assume that a |
| 3124 | * process requested a high-order can direct reclaim/compact. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3125 | */ |
Mel Gorman | b8e83b9 | 2013-07-03 15:01:45 -0700 | [diff] [blame] | 3126 | if (order && sc.nr_reclaimed >= 2UL << order) |
KOSAKI Motohiro | 73ce02e | 2009-01-06 14:40:33 -0800 | [diff] [blame] | 3127 | order = sc.order = 0; |
| 3128 | |
Mel Gorman | b8e83b9 | 2013-07-03 15:01:45 -0700 | [diff] [blame] | 3129 | /* Check if kswapd should be suspending */ |
| 3130 | if (try_to_freeze() || kthread_should_stop()) |
| 3131 | break; |
| 3132 | |
| 3133 | /* |
Mel Gorman | 2ab44f4 | 2013-07-03 15:01:47 -0700 | [diff] [blame] | 3134 | * Compact if necessary and kswapd is reclaiming at least the |
| 3135 | * high watermark number of pages as requsted |
| 3136 | */ |
| 3137 | if (pgdat_needs_compaction && sc.nr_reclaimed > nr_attempted) |
| 3138 | compact_pgdat(pgdat, order); |
| 3139 | |
| 3140 | /* |
Mel Gorman | b8e83b9 | 2013-07-03 15:01:45 -0700 | [diff] [blame] | 3141 | * Raise priority if scanning rate is too low or there was no |
| 3142 | * progress in reclaiming pages |
| 3143 | */ |
| 3144 | if (raise_priority || !sc.nr_reclaimed) |
| 3145 | sc.priority--; |
Mel Gorman | 9aa4134 | 2013-07-03 15:01:48 -0700 | [diff] [blame] | 3146 | } while (sc.priority >= 1 && |
Mel Gorman | b8e83b9 | 2013-07-03 15:01:45 -0700 | [diff] [blame] | 3147 | !pgdat_balanced(pgdat, order, *classzone_idx)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3148 | |
Mel Gorman | b8e83b9 | 2013-07-03 15:01:45 -0700 | [diff] [blame] | 3149 | out: |
Mel Gorman | 0abdee2 | 2011-01-13 15:46:22 -0800 | [diff] [blame] | 3150 | /* |
Mel Gorman | 5515061 | 2012-07-31 16:44:35 -0700 | [diff] [blame] | 3151 | * Return the order we were reclaiming at so prepare_kswapd_sleep() |
Mel Gorman | 0abdee2 | 2011-01-13 15:46:22 -0800 | [diff] [blame] | 3152 | * makes a decision on the order we were last reclaiming at. However, |
| 3153 | * if another caller entered the allocator slow path while kswapd |
| 3154 | * was awake, order will remain at the higher level |
| 3155 | */ |
Mel Gorman | dc83edd | 2011-01-13 15:46:26 -0800 | [diff] [blame] | 3156 | *classzone_idx = end_zone; |
Mel Gorman | 0abdee2 | 2011-01-13 15:46:22 -0800 | [diff] [blame] | 3157 | return order; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3158 | } |
| 3159 | |
Mel Gorman | dc83edd | 2011-01-13 15:46:26 -0800 | [diff] [blame] | 3160 | static void kswapd_try_to_sleep(pg_data_t *pgdat, int order, int classzone_idx) |
KOSAKI Motohiro | f0bc0a6 | 2011-01-13 15:45:50 -0800 | [diff] [blame] | 3161 | { |
| 3162 | long remaining = 0; |
| 3163 | DEFINE_WAIT(wait); |
| 3164 | |
| 3165 | if (freezing(current) || kthread_should_stop()) |
| 3166 | return; |
| 3167 | |
| 3168 | prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE); |
| 3169 | |
| 3170 | /* Try to sleep for a short interval */ |
Mel Gorman | 5515061 | 2012-07-31 16:44:35 -0700 | [diff] [blame] | 3171 | if (prepare_kswapd_sleep(pgdat, order, remaining, classzone_idx)) { |
KOSAKI Motohiro | f0bc0a6 | 2011-01-13 15:45:50 -0800 | [diff] [blame] | 3172 | remaining = schedule_timeout(HZ/10); |
| 3173 | finish_wait(&pgdat->kswapd_wait, &wait); |
| 3174 | prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE); |
| 3175 | } |
| 3176 | |
| 3177 | /* |
| 3178 | * After a short sleep, check if it was a premature sleep. If not, then |
| 3179 | * go fully to sleep until explicitly woken up. |
| 3180 | */ |
Mel Gorman | 5515061 | 2012-07-31 16:44:35 -0700 | [diff] [blame] | 3181 | if (prepare_kswapd_sleep(pgdat, order, remaining, classzone_idx)) { |
KOSAKI Motohiro | f0bc0a6 | 2011-01-13 15:45:50 -0800 | [diff] [blame] | 3182 | trace_mm_vmscan_kswapd_sleep(pgdat->node_id); |
| 3183 | |
| 3184 | /* |
| 3185 | * vmstat counters are not perfectly accurate and the estimated |
| 3186 | * value for counters such as NR_FREE_PAGES can deviate from the |
| 3187 | * true value by nr_online_cpus * threshold. To avoid the zone |
| 3188 | * watermarks being breached while under pressure, we reduce the |
| 3189 | * per-cpu vmstat threshold while kswapd is awake and restore |
| 3190 | * them before going back to sleep. |
| 3191 | */ |
| 3192 | set_pgdat_percpu_threshold(pgdat, calculate_normal_threshold); |
Aaditya Kumar | 1c7e7f6 | 2012-07-17 15:48:07 -0700 | [diff] [blame] | 3193 | |
Mel Gorman | 6299702 | 2012-10-08 16:32:47 -0700 | [diff] [blame] | 3194 | /* |
| 3195 | * Compaction records what page blocks it recently failed to |
| 3196 | * isolate pages from and skips them in the future scanning. |
| 3197 | * When kswapd is going to sleep, it is reasonable to assume |
| 3198 | * that pages and compaction may succeed so reset the cache. |
| 3199 | */ |
| 3200 | reset_isolation_suitable(pgdat); |
| 3201 | |
Aaditya Kumar | 1c7e7f6 | 2012-07-17 15:48:07 -0700 | [diff] [blame] | 3202 | if (!kthread_should_stop()) |
| 3203 | schedule(); |
| 3204 | |
KOSAKI Motohiro | f0bc0a6 | 2011-01-13 15:45:50 -0800 | [diff] [blame] | 3205 | set_pgdat_percpu_threshold(pgdat, calculate_pressure_threshold); |
| 3206 | } else { |
| 3207 | if (remaining) |
| 3208 | count_vm_event(KSWAPD_LOW_WMARK_HIT_QUICKLY); |
| 3209 | else |
| 3210 | count_vm_event(KSWAPD_HIGH_WMARK_HIT_QUICKLY); |
| 3211 | } |
| 3212 | finish_wait(&pgdat->kswapd_wait, &wait); |
| 3213 | } |
| 3214 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3215 | /* |
| 3216 | * The background pageout daemon, started as a kernel thread |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 3217 | * from the init process. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3218 | * |
| 3219 | * This basically trickles out pages so that we have _some_ |
| 3220 | * free memory available even if there is no other activity |
| 3221 | * that frees anything up. This is needed for things like routing |
| 3222 | * etc, where we otherwise might have all activity going on in |
| 3223 | * asynchronous contexts that cannot page things out. |
| 3224 | * |
| 3225 | * If there are applications that are active memory-allocators |
| 3226 | * (most normal use), this basically shouldn't matter. |
| 3227 | */ |
| 3228 | static int kswapd(void *p) |
| 3229 | { |
Mel Gorman | 215ddd6 | 2011-07-08 15:39:40 -0700 | [diff] [blame] | 3230 | unsigned long order, new_order; |
Alex,Shi | d2ebd0f6 | 2011-10-31 17:08:39 -0700 | [diff] [blame] | 3231 | unsigned balanced_order; |
Mel Gorman | 215ddd6 | 2011-07-08 15:39:40 -0700 | [diff] [blame] | 3232 | int classzone_idx, new_classzone_idx; |
Alex,Shi | d2ebd0f6 | 2011-10-31 17:08:39 -0700 | [diff] [blame] | 3233 | int balanced_classzone_idx; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3234 | pg_data_t *pgdat = (pg_data_t*)p; |
| 3235 | struct task_struct *tsk = current; |
KOSAKI Motohiro | f0bc0a6 | 2011-01-13 15:45:50 -0800 | [diff] [blame] | 3236 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3237 | struct reclaim_state reclaim_state = { |
| 3238 | .reclaimed_slab = 0, |
| 3239 | }; |
Rusty Russell | a70f730 | 2009-03-13 14:49:46 +1030 | [diff] [blame] | 3240 | const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3241 | |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 3242 | lockdep_set_current_reclaim_state(GFP_KERNEL); |
| 3243 | |
Rusty Russell | 174596a | 2009-01-01 10:12:29 +1030 | [diff] [blame] | 3244 | if (!cpumask_empty(cpumask)) |
Mike Travis | c5f59f0 | 2008-04-04 18:11:10 -0700 | [diff] [blame] | 3245 | set_cpus_allowed_ptr(tsk, cpumask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3246 | current->reclaim_state = &reclaim_state; |
| 3247 | |
| 3248 | /* |
| 3249 | * Tell the memory management that we're a "memory allocator", |
| 3250 | * and that if we need more memory we should get access to it |
| 3251 | * regardless (see "__alloc_pages()"). "kswapd" should |
| 3252 | * never get caught in the normal page freeing logic. |
| 3253 | * |
| 3254 | * (Kswapd normally doesn't need memory anyway, but sometimes |
| 3255 | * you need a small amount of memory in order to be able to |
| 3256 | * page out something else, and this flag essentially protects |
| 3257 | * us from recursively trying to free more memory as we're |
| 3258 | * trying to free the first piece of memory in the first place). |
| 3259 | */ |
Christoph Lameter | 930d915 | 2006-01-08 01:00:47 -0800 | [diff] [blame] | 3260 | tsk->flags |= PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD; |
Rafael J. Wysocki | 8314418 | 2007-07-17 04:03:35 -0700 | [diff] [blame] | 3261 | set_freezable(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3262 | |
Mel Gorman | 215ddd6 | 2011-07-08 15:39:40 -0700 | [diff] [blame] | 3263 | order = new_order = 0; |
Alex,Shi | d2ebd0f6 | 2011-10-31 17:08:39 -0700 | [diff] [blame] | 3264 | balanced_order = 0; |
Mel Gorman | 215ddd6 | 2011-07-08 15:39:40 -0700 | [diff] [blame] | 3265 | classzone_idx = new_classzone_idx = pgdat->nr_zones - 1; |
Alex,Shi | d2ebd0f6 | 2011-10-31 17:08:39 -0700 | [diff] [blame] | 3266 | balanced_classzone_idx = classzone_idx; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3267 | for ( ; ; ) { |
Jeff Liu | 6f6313d | 2012-12-11 16:02:48 -0800 | [diff] [blame] | 3268 | bool ret; |
Christoph Lameter | 3e1d1d2 | 2005-06-24 23:13:50 -0700 | [diff] [blame] | 3269 | |
Mel Gorman | 215ddd6 | 2011-07-08 15:39:40 -0700 | [diff] [blame] | 3270 | /* |
| 3271 | * If the last balance_pgdat was unsuccessful it's unlikely a |
| 3272 | * new request of a similar or harder type will succeed soon |
| 3273 | * so consider going to sleep on the basis we reclaimed at |
| 3274 | */ |
Alex,Shi | d2ebd0f6 | 2011-10-31 17:08:39 -0700 | [diff] [blame] | 3275 | if (balanced_classzone_idx >= new_classzone_idx && |
| 3276 | balanced_order == new_order) { |
Mel Gorman | 215ddd6 | 2011-07-08 15:39:40 -0700 | [diff] [blame] | 3277 | new_order = pgdat->kswapd_max_order; |
| 3278 | new_classzone_idx = pgdat->classzone_idx; |
| 3279 | pgdat->kswapd_max_order = 0; |
| 3280 | pgdat->classzone_idx = pgdat->nr_zones - 1; |
| 3281 | } |
| 3282 | |
Mel Gorman | 9950474 | 2011-01-13 15:46:20 -0800 | [diff] [blame] | 3283 | if (order < new_order || classzone_idx > new_classzone_idx) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3284 | /* |
| 3285 | * Don't sleep if someone wants a larger 'order' |
Mel Gorman | 9950474 | 2011-01-13 15:46:20 -0800 | [diff] [blame] | 3286 | * allocation or has tigher zone constraints |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3287 | */ |
| 3288 | order = new_order; |
Mel Gorman | 9950474 | 2011-01-13 15:46:20 -0800 | [diff] [blame] | 3289 | classzone_idx = new_classzone_idx; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3290 | } else { |
Alex,Shi | d2ebd0f6 | 2011-10-31 17:08:39 -0700 | [diff] [blame] | 3291 | kswapd_try_to_sleep(pgdat, balanced_order, |
| 3292 | balanced_classzone_idx); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3293 | order = pgdat->kswapd_max_order; |
Mel Gorman | 9950474 | 2011-01-13 15:46:20 -0800 | [diff] [blame] | 3294 | classzone_idx = pgdat->classzone_idx; |
Alex,Shi | f0dfcde | 2011-10-31 17:08:45 -0700 | [diff] [blame] | 3295 | new_order = order; |
| 3296 | new_classzone_idx = classzone_idx; |
Mel Gorman | 4d40502 | 2011-01-13 15:46:23 -0800 | [diff] [blame] | 3297 | pgdat->kswapd_max_order = 0; |
Mel Gorman | 215ddd6 | 2011-07-08 15:39:40 -0700 | [diff] [blame] | 3298 | pgdat->classzone_idx = pgdat->nr_zones - 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3299 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3300 | |
David Rientjes | 8fe23e0 | 2009-12-14 17:58:33 -0800 | [diff] [blame] | 3301 | ret = try_to_freeze(); |
| 3302 | if (kthread_should_stop()) |
| 3303 | break; |
| 3304 | |
| 3305 | /* |
| 3306 | * We can speed up thawing tasks if we don't call balance_pgdat |
| 3307 | * after returning from the refrigerator |
| 3308 | */ |
Mel Gorman | 33906bc | 2010-08-09 17:19:16 -0700 | [diff] [blame] | 3309 | if (!ret) { |
| 3310 | trace_mm_vmscan_kswapd_wake(pgdat->node_id, order); |
Alex,Shi | d2ebd0f6 | 2011-10-31 17:08:39 -0700 | [diff] [blame] | 3311 | balanced_classzone_idx = classzone_idx; |
| 3312 | balanced_order = balance_pgdat(pgdat, order, |
| 3313 | &balanced_classzone_idx); |
Mel Gorman | 33906bc | 2010-08-09 17:19:16 -0700 | [diff] [blame] | 3314 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3315 | } |
Takamori Yamaguchi | b0a8cc5 | 2012-11-08 15:53:39 -0800 | [diff] [blame] | 3316 | |
| 3317 | current->reclaim_state = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3318 | return 0; |
| 3319 | } |
| 3320 | |
| 3321 | /* |
| 3322 | * A zone is low on free memory, so wake its kswapd task to service it. |
| 3323 | */ |
Mel Gorman | 9950474 | 2011-01-13 15:46:20 -0800 | [diff] [blame] | 3324 | void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3325 | { |
| 3326 | pg_data_t *pgdat; |
| 3327 | |
Con Kolivas | f3fe651 | 2006-01-06 00:11:15 -0800 | [diff] [blame] | 3328 | if (!populated_zone(zone)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3329 | return; |
| 3330 | |
Paul Jackson | 02a0e53 | 2006-12-13 00:34:25 -0800 | [diff] [blame] | 3331 | if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3332 | return; |
Mel Gorman | 88f5acf | 2011-01-13 15:45:41 -0800 | [diff] [blame] | 3333 | pgdat = zone->zone_pgdat; |
Mel Gorman | 9950474 | 2011-01-13 15:46:20 -0800 | [diff] [blame] | 3334 | if (pgdat->kswapd_max_order < order) { |
Mel Gorman | 88f5acf | 2011-01-13 15:45:41 -0800 | [diff] [blame] | 3335 | pgdat->kswapd_max_order = order; |
Mel Gorman | 9950474 | 2011-01-13 15:46:20 -0800 | [diff] [blame] | 3336 | pgdat->classzone_idx = min(pgdat->classzone_idx, classzone_idx); |
| 3337 | } |
Con Kolivas | 8d0986e | 2005-09-13 01:25:07 -0700 | [diff] [blame] | 3338 | if (!waitqueue_active(&pgdat->kswapd_wait)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3339 | return; |
Johannes Weiner | 892f795 | 2013-09-11 14:20:39 -0700 | [diff] [blame] | 3340 | if (zone_balanced(zone, order, 0, 0)) |
Mel Gorman | 88f5acf | 2011-01-13 15:45:41 -0800 | [diff] [blame] | 3341 | return; |
| 3342 | |
| 3343 | trace_mm_vmscan_wakeup_kswapd(pgdat->node_id, zone_idx(zone), order); |
Con Kolivas | 8d0986e | 2005-09-13 01:25:07 -0700 | [diff] [blame] | 3344 | wake_up_interruptible(&pgdat->kswapd_wait); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3345 | } |
| 3346 | |
Rafael J. Wysocki | c6f37f1 | 2009-05-24 22:16:31 +0200 | [diff] [blame] | 3347 | #ifdef CONFIG_HIBERNATION |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3348 | /* |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame] | 3349 | * Try to free `nr_to_reclaim' of memory, system-wide, and return the number of |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 3350 | * freed pages. |
| 3351 | * |
| 3352 | * Rather than trying to age LRUs the aim is to preserve the overall |
| 3353 | * LRU order by reclaiming preferentially |
| 3354 | * inactive > active > active referenced > active mapped |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3355 | */ |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame] | 3356 | unsigned long shrink_all_memory(unsigned long nr_to_reclaim) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3357 | { |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 3358 | struct reclaim_state reclaim_state; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 3359 | struct scan_control sc = { |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame] | 3360 | .gfp_mask = GFP_HIGHUSER_MOVABLE, |
| 3361 | .may_swap = 1, |
| 3362 | .may_unmap = 1, |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 3363 | .may_writepage = 1, |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame] | 3364 | .nr_to_reclaim = nr_to_reclaim, |
| 3365 | .hibernation_mode = 1, |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame] | 3366 | .order = 0, |
Konstantin Khlebnikov | 9e3b2f8 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 3367 | .priority = DEF_PRIORITY, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3368 | }; |
Ying Han | a09ed5e | 2011-05-24 17:12:26 -0700 | [diff] [blame] | 3369 | struct zonelist *zonelist = node_zonelist(numa_node_id(), sc.gfp_mask); |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame] | 3370 | struct task_struct *p = current; |
| 3371 | unsigned long nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3372 | |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame] | 3373 | p->flags |= PF_MEMALLOC; |
| 3374 | lockdep_set_current_reclaim_state(sc.gfp_mask); |
| 3375 | reclaim_state.reclaimed_slab = 0; |
| 3376 | p->reclaim_state = &reclaim_state; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 3377 | |
Vladimir Davydov | 3115cd9 | 2014-04-03 14:47:22 -0700 | [diff] [blame] | 3378 | nr_reclaimed = do_try_to_free_pages(zonelist, &sc); |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 3379 | |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame] | 3380 | p->reclaim_state = NULL; |
| 3381 | lockdep_clear_current_reclaim_state(); |
| 3382 | p->flags &= ~PF_MEMALLOC; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 3383 | |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame] | 3384 | return nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3385 | } |
Rafael J. Wysocki | c6f37f1 | 2009-05-24 22:16:31 +0200 | [diff] [blame] | 3386 | #endif /* CONFIG_HIBERNATION */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3387 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3388 | /* It's optimal to keep kswapds on the same CPUs as their memory, but |
| 3389 | not required for correctness. So if the last cpu in a node goes |
| 3390 | away, we get changed to run anywhere: as the first one comes back, |
| 3391 | restore their cpu bindings. */ |
Greg Kroah-Hartman | fcb35a9 | 2012-12-21 15:01:06 -0800 | [diff] [blame] | 3392 | static int cpu_callback(struct notifier_block *nfb, unsigned long action, |
| 3393 | void *hcpu) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3394 | { |
Yasunori Goto | 58c0a4a | 2007-10-16 01:25:40 -0700 | [diff] [blame] | 3395 | int nid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3396 | |
Rafael J. Wysocki | 8bb7844 | 2007-05-09 02:35:10 -0700 | [diff] [blame] | 3397 | if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN) { |
Lai Jiangshan | 48fb2e2 | 2012-12-12 13:51:43 -0800 | [diff] [blame] | 3398 | for_each_node_state(nid, N_MEMORY) { |
Mike Travis | c5f59f0 | 2008-04-04 18:11:10 -0700 | [diff] [blame] | 3399 | pg_data_t *pgdat = NODE_DATA(nid); |
Rusty Russell | a70f730 | 2009-03-13 14:49:46 +1030 | [diff] [blame] | 3400 | const struct cpumask *mask; |
| 3401 | |
| 3402 | mask = cpumask_of_node(pgdat->node_id); |
Mike Travis | c5f59f0 | 2008-04-04 18:11:10 -0700 | [diff] [blame] | 3403 | |
Rusty Russell | 3e59794 | 2009-01-01 10:12:24 +1030 | [diff] [blame] | 3404 | if (cpumask_any_and(cpu_online_mask, mask) < nr_cpu_ids) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3405 | /* One of our CPUs online: restore mask */ |
Mike Travis | c5f59f0 | 2008-04-04 18:11:10 -0700 | [diff] [blame] | 3406 | set_cpus_allowed_ptr(pgdat->kswapd, mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3407 | } |
| 3408 | } |
| 3409 | return NOTIFY_OK; |
| 3410 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3411 | |
Yasunori Goto | 3218ae1 | 2006-06-27 02:53:33 -0700 | [diff] [blame] | 3412 | /* |
| 3413 | * This kswapd start function will be called by init and node-hot-add. |
| 3414 | * On node-hot-add, kswapd will moved to proper cpus if cpus are hot-added. |
| 3415 | */ |
| 3416 | int kswapd_run(int nid) |
| 3417 | { |
| 3418 | pg_data_t *pgdat = NODE_DATA(nid); |
| 3419 | int ret = 0; |
| 3420 | |
| 3421 | if (pgdat->kswapd) |
| 3422 | return 0; |
| 3423 | |
| 3424 | pgdat->kswapd = kthread_run(kswapd, pgdat, "kswapd%d", nid); |
| 3425 | if (IS_ERR(pgdat->kswapd)) { |
| 3426 | /* failure at boot is fatal */ |
| 3427 | BUG_ON(system_state == SYSTEM_BOOTING); |
Gavin Shan | d5dc0ad | 2012-10-08 16:29:27 -0700 | [diff] [blame] | 3428 | pr_err("Failed to start kswapd on node %d\n", nid); |
| 3429 | ret = PTR_ERR(pgdat->kswapd); |
Xishi Qiu | d72515b | 2013-04-17 15:58:34 -0700 | [diff] [blame] | 3430 | pgdat->kswapd = NULL; |
Yasunori Goto | 3218ae1 | 2006-06-27 02:53:33 -0700 | [diff] [blame] | 3431 | } |
| 3432 | return ret; |
| 3433 | } |
| 3434 | |
David Rientjes | 8fe23e0 | 2009-12-14 17:58:33 -0800 | [diff] [blame] | 3435 | /* |
Jiang Liu | d8adde1 | 2012-07-11 14:01:52 -0700 | [diff] [blame] | 3436 | * Called by memory hotplug when all memory in a node is offlined. Caller must |
Vladimir Davydov | bfc8c90 | 2014-06-04 16:07:18 -0700 | [diff] [blame] | 3437 | * hold mem_hotplug_begin/end(). |
David Rientjes | 8fe23e0 | 2009-12-14 17:58:33 -0800 | [diff] [blame] | 3438 | */ |
| 3439 | void kswapd_stop(int nid) |
| 3440 | { |
| 3441 | struct task_struct *kswapd = NODE_DATA(nid)->kswapd; |
| 3442 | |
Jiang Liu | d8adde1 | 2012-07-11 14:01:52 -0700 | [diff] [blame] | 3443 | if (kswapd) { |
David Rientjes | 8fe23e0 | 2009-12-14 17:58:33 -0800 | [diff] [blame] | 3444 | kthread_stop(kswapd); |
Jiang Liu | d8adde1 | 2012-07-11 14:01:52 -0700 | [diff] [blame] | 3445 | NODE_DATA(nid)->kswapd = NULL; |
| 3446 | } |
David Rientjes | 8fe23e0 | 2009-12-14 17:58:33 -0800 | [diff] [blame] | 3447 | } |
| 3448 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3449 | static int __init kswapd_init(void) |
| 3450 | { |
Yasunori Goto | 3218ae1 | 2006-06-27 02:53:33 -0700 | [diff] [blame] | 3451 | int nid; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 3452 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3453 | swap_setup(); |
Lai Jiangshan | 48fb2e2 | 2012-12-12 13:51:43 -0800 | [diff] [blame] | 3454 | for_each_node_state(nid, N_MEMORY) |
Yasunori Goto | 3218ae1 | 2006-06-27 02:53:33 -0700 | [diff] [blame] | 3455 | kswapd_run(nid); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3456 | hotcpu_notifier(cpu_callback, 0); |
| 3457 | return 0; |
| 3458 | } |
| 3459 | |
| 3460 | module_init(kswapd_init) |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 3461 | |
| 3462 | #ifdef CONFIG_NUMA |
| 3463 | /* |
| 3464 | * Zone reclaim mode |
| 3465 | * |
| 3466 | * If non-zero call zone_reclaim when the number of free pages falls below |
| 3467 | * the watermarks. |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 3468 | */ |
| 3469 | int zone_reclaim_mode __read_mostly; |
| 3470 | |
Christoph Lameter | 1b2ffb7 | 2006-02-01 03:05:34 -0800 | [diff] [blame] | 3471 | #define RECLAIM_OFF 0 |
Fernando Luis Vazquez Cao | 7d03431 | 2008-07-29 22:33:41 -0700 | [diff] [blame] | 3472 | #define RECLAIM_ZONE (1<<0) /* Run shrink_inactive_list on the zone */ |
Christoph Lameter | 1b2ffb7 | 2006-02-01 03:05:34 -0800 | [diff] [blame] | 3473 | #define RECLAIM_WRITE (1<<1) /* Writeout pages during reclaim */ |
| 3474 | #define RECLAIM_SWAP (1<<2) /* Swap pages out during reclaim */ |
| 3475 | |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 3476 | /* |
Christoph Lameter | a92f712 | 2006-02-01 03:05:32 -0800 | [diff] [blame] | 3477 | * Priority for ZONE_RECLAIM. This determines the fraction of pages |
| 3478 | * of a node considered for each zone_reclaim. 4 scans 1/16th of |
| 3479 | * a zone. |
| 3480 | */ |
| 3481 | #define ZONE_RECLAIM_PRIORITY 4 |
| 3482 | |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 3483 | /* |
Christoph Lameter | 9614634 | 2006-07-03 00:24:13 -0700 | [diff] [blame] | 3484 | * Percentage of pages in a zone that must be unmapped for zone_reclaim to |
| 3485 | * occur. |
| 3486 | */ |
| 3487 | int sysctl_min_unmapped_ratio = 1; |
| 3488 | |
| 3489 | /* |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 3490 | * If the number of slab pages in a zone grows beyond this percentage then |
| 3491 | * slab reclaim needs to occur. |
| 3492 | */ |
| 3493 | int sysctl_min_slab_ratio = 5; |
| 3494 | |
Mel Gorman | 90afa5d | 2009-06-16 15:33:20 -0700 | [diff] [blame] | 3495 | static inline unsigned long zone_unmapped_file_pages(struct zone *zone) |
| 3496 | { |
| 3497 | unsigned long file_mapped = zone_page_state(zone, NR_FILE_MAPPED); |
| 3498 | unsigned long file_lru = zone_page_state(zone, NR_INACTIVE_FILE) + |
| 3499 | zone_page_state(zone, NR_ACTIVE_FILE); |
| 3500 | |
| 3501 | /* |
| 3502 | * It's possible for there to be more file mapped pages than |
| 3503 | * accounted for by the pages on the file LRU lists because |
| 3504 | * tmpfs pages accounted for as ANON can also be FILE_MAPPED |
| 3505 | */ |
| 3506 | return (file_lru > file_mapped) ? (file_lru - file_mapped) : 0; |
| 3507 | } |
| 3508 | |
| 3509 | /* Work out how many page cache pages we can reclaim in this reclaim_mode */ |
| 3510 | static long zone_pagecache_reclaimable(struct zone *zone) |
| 3511 | { |
| 3512 | long nr_pagecache_reclaimable; |
| 3513 | long delta = 0; |
| 3514 | |
| 3515 | /* |
| 3516 | * If RECLAIM_SWAP is set, then all file pages are considered |
| 3517 | * potentially reclaimable. Otherwise, we have to worry about |
| 3518 | * pages like swapcache and zone_unmapped_file_pages() provides |
| 3519 | * a better estimate |
| 3520 | */ |
| 3521 | if (zone_reclaim_mode & RECLAIM_SWAP) |
| 3522 | nr_pagecache_reclaimable = zone_page_state(zone, NR_FILE_PAGES); |
| 3523 | else |
| 3524 | nr_pagecache_reclaimable = zone_unmapped_file_pages(zone); |
| 3525 | |
| 3526 | /* If we can't clean pages, remove dirty pages from consideration */ |
| 3527 | if (!(zone_reclaim_mode & RECLAIM_WRITE)) |
| 3528 | delta += zone_page_state(zone, NR_FILE_DIRTY); |
| 3529 | |
| 3530 | /* Watch for any possible underflows due to delta */ |
| 3531 | if (unlikely(delta > nr_pagecache_reclaimable)) |
| 3532 | delta = nr_pagecache_reclaimable; |
| 3533 | |
| 3534 | return nr_pagecache_reclaimable - delta; |
| 3535 | } |
| 3536 | |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 3537 | /* |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 3538 | * Try to free up some pages from this zone through reclaim. |
| 3539 | */ |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 3540 | static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 3541 | { |
Christoph Lameter | 7fb2d46 | 2006-03-22 00:08:22 -0800 | [diff] [blame] | 3542 | /* Minimum pages needed in order to stay on node */ |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 3543 | const unsigned long nr_pages = 1 << order; |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 3544 | struct task_struct *p = current; |
| 3545 | struct reclaim_state reclaim_state; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 3546 | struct scan_control sc = { |
| 3547 | .may_writepage = !!(zone_reclaim_mode & RECLAIM_WRITE), |
Johannes Weiner | a6dc60f8 | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 3548 | .may_unmap = !!(zone_reclaim_mode & RECLAIM_SWAP), |
KOSAKI Motohiro | 2e2e425 | 2009-04-21 12:24:57 -0700 | [diff] [blame] | 3549 | .may_swap = 1, |
Andrew Morton | 62b726c | 2013-02-22 16:32:24 -0800 | [diff] [blame] | 3550 | .nr_to_reclaim = max(nr_pages, SWAP_CLUSTER_MAX), |
Ming Lei | 21caf2f | 2013-02-22 16:34:08 -0800 | [diff] [blame] | 3551 | .gfp_mask = (gfp_mask = memalloc_noio_flags(gfp_mask)), |
Johannes Weiner | bd2f619 | 2009-03-31 15:19:38 -0700 | [diff] [blame] | 3552 | .order = order, |
Konstantin Khlebnikov | 9e3b2f8 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 3553 | .priority = ZONE_RECLAIM_PRIORITY, |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 3554 | }; |
Ying Han | a09ed5e | 2011-05-24 17:12:26 -0700 | [diff] [blame] | 3555 | struct shrink_control shrink = { |
| 3556 | .gfp_mask = sc.gfp_mask, |
| 3557 | }; |
KOSAKI Motohiro | 1574804 | 2010-08-09 17:19:50 -0700 | [diff] [blame] | 3558 | unsigned long nr_slab_pages0, nr_slab_pages1; |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 3559 | |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 3560 | cond_resched(); |
Christoph Lameter | d4f7796 | 2006-02-24 13:04:22 -0800 | [diff] [blame] | 3561 | /* |
| 3562 | * We need to be able to allocate from the reserves for RECLAIM_SWAP |
| 3563 | * and we also need to be able to write out pages for RECLAIM_WRITE |
| 3564 | * and RECLAIM_SWAP. |
| 3565 | */ |
| 3566 | p->flags |= PF_MEMALLOC | PF_SWAPWRITE; |
KOSAKI Motohiro | 76ca542 | 2010-03-05 13:41:47 -0800 | [diff] [blame] | 3567 | lockdep_set_current_reclaim_state(gfp_mask); |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 3568 | reclaim_state.reclaimed_slab = 0; |
| 3569 | p->reclaim_state = &reclaim_state; |
Christoph Lameter | c84db23 | 2006-02-01 03:05:29 -0800 | [diff] [blame] | 3570 | |
Mel Gorman | 90afa5d | 2009-06-16 15:33:20 -0700 | [diff] [blame] | 3571 | if (zone_pagecache_reclaimable(zone) > zone->min_unmapped_pages) { |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 3572 | /* |
| 3573 | * Free memory by calling shrink zone with increasing |
| 3574 | * priorities until we have enough memory freed. |
| 3575 | */ |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 3576 | do { |
Konstantin Khlebnikov | 9e3b2f8 | 2012-05-29 15:06:57 -0700 | [diff] [blame] | 3577 | shrink_zone(zone, &sc); |
| 3578 | } while (sc.nr_reclaimed < nr_pages && --sc.priority >= 0); |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 3579 | } |
Christoph Lameter | c84db23 | 2006-02-01 03:05:29 -0800 | [diff] [blame] | 3580 | |
KOSAKI Motohiro | 1574804 | 2010-08-09 17:19:50 -0700 | [diff] [blame] | 3581 | nr_slab_pages0 = zone_page_state(zone, NR_SLAB_RECLAIMABLE); |
| 3582 | if (nr_slab_pages0 > zone->min_slab_pages) { |
Christoph Lameter | 2a16e3f | 2006-02-01 03:05:35 -0800 | [diff] [blame] | 3583 | /* |
Christoph Lameter | 7fb2d46 | 2006-03-22 00:08:22 -0800 | [diff] [blame] | 3584 | * shrink_slab() does not currently allow us to determine how |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 3585 | * many pages were freed in this zone. So we take the current |
| 3586 | * number of slab pages and shake the slab until it is reduced |
| 3587 | * by the same nr_pages that we used for reclaiming unmapped |
| 3588 | * pages. |
Christoph Lameter | 2a16e3f | 2006-02-01 03:05:35 -0800 | [diff] [blame] | 3589 | */ |
Dave Chinner | 0ce3d74 | 2013-08-28 10:18:03 +1000 | [diff] [blame] | 3590 | nodes_clear(shrink.nodes_to_scan); |
| 3591 | node_set(zone_to_nid(zone), shrink.nodes_to_scan); |
KOSAKI Motohiro | 4dc4b3d | 2010-08-09 17:19:54 -0700 | [diff] [blame] | 3592 | for (;;) { |
| 3593 | unsigned long lru_pages = zone_reclaimable_pages(zone); |
| 3594 | |
| 3595 | /* No reclaimable slab or very low memory pressure */ |
Ying Han | 1495f23 | 2011-05-24 17:12:27 -0700 | [diff] [blame] | 3596 | if (!shrink_slab(&shrink, sc.nr_scanned, lru_pages)) |
KOSAKI Motohiro | 4dc4b3d | 2010-08-09 17:19:54 -0700 | [diff] [blame] | 3597 | break; |
| 3598 | |
| 3599 | /* Freed enough memory */ |
| 3600 | nr_slab_pages1 = zone_page_state(zone, |
| 3601 | NR_SLAB_RECLAIMABLE); |
| 3602 | if (nr_slab_pages1 + nr_pages <= nr_slab_pages0) |
| 3603 | break; |
| 3604 | } |
Christoph Lameter | 83e33a4 | 2006-09-25 23:31:53 -0700 | [diff] [blame] | 3605 | |
| 3606 | /* |
| 3607 | * Update nr_reclaimed by the number of slab pages we |
| 3608 | * reclaimed from this zone. |
| 3609 | */ |
KOSAKI Motohiro | 1574804 | 2010-08-09 17:19:50 -0700 | [diff] [blame] | 3610 | nr_slab_pages1 = zone_page_state(zone, NR_SLAB_RECLAIMABLE); |
| 3611 | if (nr_slab_pages1 < nr_slab_pages0) |
| 3612 | sc.nr_reclaimed += nr_slab_pages0 - nr_slab_pages1; |
Christoph Lameter | 2a16e3f | 2006-02-01 03:05:35 -0800 | [diff] [blame] | 3613 | } |
| 3614 | |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 3615 | p->reclaim_state = NULL; |
Christoph Lameter | d4f7796 | 2006-02-24 13:04:22 -0800 | [diff] [blame] | 3616 | current->flags &= ~(PF_MEMALLOC | PF_SWAPWRITE); |
KOSAKI Motohiro | 76ca542 | 2010-03-05 13:41:47 -0800 | [diff] [blame] | 3617 | lockdep_clear_current_reclaim_state(); |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 3618 | return sc.nr_reclaimed >= nr_pages; |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 3619 | } |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 3620 | |
| 3621 | int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) |
| 3622 | { |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 3623 | int node_id; |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 3624 | int ret; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 3625 | |
| 3626 | /* |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 3627 | * Zone reclaim reclaims unmapped file backed pages and |
| 3628 | * slab pages if we are over the defined limits. |
Christoph Lameter | 34aa133 | 2006-06-30 01:55:37 -0700 | [diff] [blame] | 3629 | * |
Christoph Lameter | 9614634 | 2006-07-03 00:24:13 -0700 | [diff] [blame] | 3630 | * A small portion of unmapped file backed pages is needed for |
| 3631 | * file I/O otherwise pages read by file I/O will be immediately |
| 3632 | * thrown out if the zone is overallocated. So we do not reclaim |
| 3633 | * if less than a specified percentage of the zone is used by |
| 3634 | * unmapped file backed pages. |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 3635 | */ |
Mel Gorman | 90afa5d | 2009-06-16 15:33:20 -0700 | [diff] [blame] | 3636 | if (zone_pagecache_reclaimable(zone) <= zone->min_unmapped_pages && |
| 3637 | zone_page_state(zone, NR_SLAB_RECLAIMABLE) <= zone->min_slab_pages) |
Mel Gorman | fa5e084 | 2009-06-16 15:33:22 -0700 | [diff] [blame] | 3638 | return ZONE_RECLAIM_FULL; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 3639 | |
Lisa Du | 6e543d5 | 2013-09-11 14:22:36 -0700 | [diff] [blame] | 3640 | if (!zone_reclaimable(zone)) |
Mel Gorman | fa5e084 | 2009-06-16 15:33:22 -0700 | [diff] [blame] | 3641 | return ZONE_RECLAIM_FULL; |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 3642 | |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 3643 | /* |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 3644 | * Do not scan if the allocation should not be delayed. |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 3645 | */ |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 3646 | if (!(gfp_mask & __GFP_WAIT) || (current->flags & PF_MEMALLOC)) |
Mel Gorman | fa5e084 | 2009-06-16 15:33:22 -0700 | [diff] [blame] | 3647 | return ZONE_RECLAIM_NOSCAN; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 3648 | |
| 3649 | /* |
| 3650 | * Only run zone reclaim on the local zone or on zones that do not |
| 3651 | * have associated processors. This will favor the local processor |
| 3652 | * over remote processors and spread off node memory allocations |
| 3653 | * as wide as possible. |
| 3654 | */ |
Christoph Lameter | 89fa302 | 2006-09-25 23:31:55 -0700 | [diff] [blame] | 3655 | node_id = zone_to_nid(zone); |
Christoph Lameter | 37c0708 | 2007-10-16 01:25:36 -0700 | [diff] [blame] | 3656 | if (node_state(node_id, N_CPU) && node_id != numa_node_id()) |
Mel Gorman | fa5e084 | 2009-06-16 15:33:22 -0700 | [diff] [blame] | 3657 | return ZONE_RECLAIM_NOSCAN; |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 3658 | |
| 3659 | if (zone_test_and_set_flag(zone, ZONE_RECLAIM_LOCKED)) |
Mel Gorman | fa5e084 | 2009-06-16 15:33:22 -0700 | [diff] [blame] | 3660 | return ZONE_RECLAIM_NOSCAN; |
| 3661 | |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 3662 | ret = __zone_reclaim(zone, gfp_mask, order); |
| 3663 | zone_clear_flag(zone, ZONE_RECLAIM_LOCKED); |
| 3664 | |
Mel Gorman | 24cf72518 | 2009-06-16 15:33:23 -0700 | [diff] [blame] | 3665 | if (!ret) |
| 3666 | count_vm_event(PGSCAN_ZONE_RECLAIM_FAILED); |
| 3667 | |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 3668 | return ret; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 3669 | } |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 3670 | #endif |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 3671 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 3672 | /* |
| 3673 | * page_evictable - test whether a page is evictable |
| 3674 | * @page: the page to test |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 3675 | * |
| 3676 | * Test whether page is evictable--i.e., should be placed on active/inactive |
Hugh Dickins | 39b5f29 | 2012-10-08 16:33:18 -0700 | [diff] [blame] | 3677 | * lists vs unevictable list. |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 3678 | * |
| 3679 | * Reasons page might not be evictable: |
Lee Schermerhorn | ba9ddf4 | 2008-10-18 20:26:42 -0700 | [diff] [blame] | 3680 | * (1) page's mapping marked unevictable |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 3681 | * (2) page is part of an mlocked VMA |
Lee Schermerhorn | ba9ddf4 | 2008-10-18 20:26:42 -0700 | [diff] [blame] | 3682 | * |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 3683 | */ |
Hugh Dickins | 39b5f29 | 2012-10-08 16:33:18 -0700 | [diff] [blame] | 3684 | int page_evictable(struct page *page) |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 3685 | { |
Hugh Dickins | 39b5f29 | 2012-10-08 16:33:18 -0700 | [diff] [blame] | 3686 | return !mapping_unevictable(page_mapping(page)) && !PageMlocked(page); |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 3687 | } |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 3688 | |
Hugh Dickins | 85046579 | 2012-01-20 14:34:19 -0800 | [diff] [blame] | 3689 | #ifdef CONFIG_SHMEM |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 3690 | /** |
Hugh Dickins | 2451326 | 2012-01-20 14:34:21 -0800 | [diff] [blame] | 3691 | * check_move_unevictable_pages - check pages for evictability and move to appropriate zone lru list |
| 3692 | * @pages: array of pages to check |
| 3693 | * @nr_pages: number of pages to check |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 3694 | * |
Hugh Dickins | 2451326 | 2012-01-20 14:34:21 -0800 | [diff] [blame] | 3695 | * Checks pages for evictability and moves them to the appropriate lru list. |
Hugh Dickins | 85046579 | 2012-01-20 14:34:19 -0800 | [diff] [blame] | 3696 | * |
| 3697 | * This function is only used for SysV IPC SHM_UNLOCK. |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 3698 | */ |
Hugh Dickins | 2451326 | 2012-01-20 14:34:21 -0800 | [diff] [blame] | 3699 | void check_move_unevictable_pages(struct page **pages, int nr_pages) |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 3700 | { |
Johannes Weiner | 925b767 | 2012-01-12 17:18:15 -0800 | [diff] [blame] | 3701 | struct lruvec *lruvec; |
Hugh Dickins | 2451326 | 2012-01-20 14:34:21 -0800 | [diff] [blame] | 3702 | struct zone *zone = NULL; |
| 3703 | int pgscanned = 0; |
| 3704 | int pgrescued = 0; |
| 3705 | int i; |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 3706 | |
Hugh Dickins | 2451326 | 2012-01-20 14:34:21 -0800 | [diff] [blame] | 3707 | for (i = 0; i < nr_pages; i++) { |
| 3708 | struct page *page = pages[i]; |
| 3709 | struct zone *pagezone; |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 3710 | |
Hugh Dickins | 2451326 | 2012-01-20 14:34:21 -0800 | [diff] [blame] | 3711 | pgscanned++; |
| 3712 | pagezone = page_zone(page); |
| 3713 | if (pagezone != zone) { |
| 3714 | if (zone) |
| 3715 | spin_unlock_irq(&zone->lru_lock); |
| 3716 | zone = pagezone; |
| 3717 | spin_lock_irq(&zone->lru_lock); |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 3718 | } |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 3719 | lruvec = mem_cgroup_page_lruvec(page, zone); |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 3720 | |
Hugh Dickins | 2451326 | 2012-01-20 14:34:21 -0800 | [diff] [blame] | 3721 | if (!PageLRU(page) || !PageUnevictable(page)) |
| 3722 | continue; |
| 3723 | |
Hugh Dickins | 39b5f29 | 2012-10-08 16:33:18 -0700 | [diff] [blame] | 3724 | if (page_evictable(page)) { |
Hugh Dickins | 2451326 | 2012-01-20 14:34:21 -0800 | [diff] [blame] | 3725 | enum lru_list lru = page_lru_base_type(page); |
| 3726 | |
Sasha Levin | 309381fea | 2014-01-23 15:52:54 -0800 | [diff] [blame] | 3727 | VM_BUG_ON_PAGE(PageActive(page), page); |
Hugh Dickins | 2451326 | 2012-01-20 14:34:21 -0800 | [diff] [blame] | 3728 | ClearPageUnevictable(page); |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 3729 | del_page_from_lru_list(page, lruvec, LRU_UNEVICTABLE); |
| 3730 | add_page_to_lru_list(page, lruvec, lru); |
Hugh Dickins | 2451326 | 2012-01-20 14:34:21 -0800 | [diff] [blame] | 3731 | pgrescued++; |
| 3732 | } |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 3733 | } |
Hugh Dickins | 2451326 | 2012-01-20 14:34:21 -0800 | [diff] [blame] | 3734 | |
| 3735 | if (zone) { |
| 3736 | __count_vm_events(UNEVICTABLE_PGRESCUED, pgrescued); |
| 3737 | __count_vm_events(UNEVICTABLE_PGSCANNED, pgscanned); |
| 3738 | spin_unlock_irq(&zone->lru_lock); |
| 3739 | } |
Hugh Dickins | 85046579 | 2012-01-20 14:34:19 -0800 | [diff] [blame] | 3740 | } |
| 3741 | #endif /* CONFIG_SHMEM */ |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 3742 | |
Johannes Weiner | 264e56d | 2011-10-31 17:09:13 -0700 | [diff] [blame] | 3743 | static void warn_scan_unevictable_pages(void) |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 3744 | { |
Johannes Weiner | 264e56d | 2011-10-31 17:09:13 -0700 | [diff] [blame] | 3745 | printk_once(KERN_WARNING |
KOSAKI Motohiro | 25bd91b | 2012-01-10 15:07:40 -0800 | [diff] [blame] | 3746 | "%s: The scan_unevictable_pages sysctl/node-interface has been " |
Johannes Weiner | 264e56d | 2011-10-31 17:09:13 -0700 | [diff] [blame] | 3747 | "disabled for lack of a legitimate use case. If you have " |
KOSAKI Motohiro | 25bd91b | 2012-01-10 15:07:40 -0800 | [diff] [blame] | 3748 | "one, please send an email to linux-mm@kvack.org.\n", |
| 3749 | current->comm); |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 3750 | } |
| 3751 | |
| 3752 | /* |
| 3753 | * scan_unevictable_pages [vm] sysctl handler. On demand re-scan of |
| 3754 | * all nodes' unevictable lists for evictable pages |
| 3755 | */ |
| 3756 | unsigned long scan_unevictable_pages; |
| 3757 | |
| 3758 | int scan_unevictable_handler(struct ctl_table *table, int write, |
Alexey Dobriyan | 8d65af7 | 2009-09-23 15:57:19 -0700 | [diff] [blame] | 3759 | void __user *buffer, |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 3760 | size_t *length, loff_t *ppos) |
| 3761 | { |
Johannes Weiner | 264e56d | 2011-10-31 17:09:13 -0700 | [diff] [blame] | 3762 | warn_scan_unevictable_pages(); |
Alexey Dobriyan | 8d65af7 | 2009-09-23 15:57:19 -0700 | [diff] [blame] | 3763 | proc_doulongvec_minmax(table, write, buffer, length, ppos); |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 3764 | scan_unevictable_pages = 0; |
| 3765 | return 0; |
| 3766 | } |
| 3767 | |
Thadeu Lima de Souza Cascardo | e4455ab | 2010-10-26 14:21:28 -0700 | [diff] [blame] | 3768 | #ifdef CONFIG_NUMA |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 3769 | /* |
| 3770 | * per node 'scan_unevictable_pages' attribute. On demand re-scan of |
| 3771 | * a specified node's per zone unevictable lists for evictable pages. |
| 3772 | */ |
| 3773 | |
Kay Sievers | 10fbcf4 | 2011-12-21 14:48:43 -0800 | [diff] [blame] | 3774 | static ssize_t read_scan_unevictable_node(struct device *dev, |
| 3775 | struct device_attribute *attr, |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 3776 | char *buf) |
| 3777 | { |
Johannes Weiner | 264e56d | 2011-10-31 17:09:13 -0700 | [diff] [blame] | 3778 | warn_scan_unevictable_pages(); |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 3779 | return sprintf(buf, "0\n"); /* always zero; should fit... */ |
| 3780 | } |
| 3781 | |
Kay Sievers | 10fbcf4 | 2011-12-21 14:48:43 -0800 | [diff] [blame] | 3782 | static ssize_t write_scan_unevictable_node(struct device *dev, |
| 3783 | struct device_attribute *attr, |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 3784 | const char *buf, size_t count) |
| 3785 | { |
Johannes Weiner | 264e56d | 2011-10-31 17:09:13 -0700 | [diff] [blame] | 3786 | warn_scan_unevictable_pages(); |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 3787 | return 1; |
| 3788 | } |
| 3789 | |
| 3790 | |
Kay Sievers | 10fbcf4 | 2011-12-21 14:48:43 -0800 | [diff] [blame] | 3791 | static DEVICE_ATTR(scan_unevictable_pages, S_IRUGO | S_IWUSR, |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 3792 | read_scan_unevictable_node, |
| 3793 | write_scan_unevictable_node); |
| 3794 | |
| 3795 | int scan_unevictable_register_node(struct node *node) |
| 3796 | { |
Kay Sievers | 10fbcf4 | 2011-12-21 14:48:43 -0800 | [diff] [blame] | 3797 | return device_create_file(&node->dev, &dev_attr_scan_unevictable_pages); |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 3798 | } |
| 3799 | |
| 3800 | void scan_unevictable_unregister_node(struct node *node) |
| 3801 | { |
Kay Sievers | 10fbcf4 | 2011-12-21 14:48:43 -0800 | [diff] [blame] | 3802 | device_remove_file(&node->dev, &dev_attr_scan_unevictable_pages); |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 3803 | } |
Thadeu Lima de Souza Cascardo | e4455ab | 2010-10-26 14:21:28 -0700 | [diff] [blame] | 3804 | #endif |