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> |
Andrew Morton | e129b5c | 2006-09-27 01:50:00 -0700 | [diff] [blame] | 22 | #include <linux/vmstat.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 23 | #include <linux/file.h> |
| 24 | #include <linux/writeback.h> |
| 25 | #include <linux/blkdev.h> |
| 26 | #include <linux/buffer_head.h> /* for try_to_release_page(), |
| 27 | buffer_heads_over_limit */ |
| 28 | #include <linux/mm_inline.h> |
| 29 | #include <linux/pagevec.h> |
| 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> |
| 35 | #include <linux/notifier.h> |
| 36 | #include <linux/rwsem.h> |
Rafael J. Wysocki | 248a030 | 2006-03-22 00:09:04 -0800 | [diff] [blame] | 37 | #include <linux/delay.h> |
Yasunori Goto | 3218ae1 | 2006-06-27 02:53:33 -0700 | [diff] [blame] | 38 | #include <linux/kthread.h> |
Nigel Cunningham | 7dfb710 | 2006-12-06 20:34:23 -0800 | [diff] [blame] | 39 | #include <linux/freezer.h> |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 40 | #include <linux/memcontrol.h> |
Keika Kobayashi | 873b477 | 2008-07-25 01:48:52 -0700 | [diff] [blame] | 41 | #include <linux/delayacct.h> |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 42 | #include <linux/sysctl.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | |
| 44 | #include <asm/tlbflush.h> |
| 45 | #include <asm/div64.h> |
| 46 | |
| 47 | #include <linux/swapops.h> |
| 48 | |
Nick Piggin | 0f8053a | 2006-03-22 00:08:33 -0800 | [diff] [blame] | 49 | #include "internal.h" |
| 50 | |
Mel Gorman | 33906bc | 2010-08-09 17:19:16 -0700 | [diff] [blame] | 51 | #define CREATE_TRACE_POINTS |
| 52 | #include <trace/events/vmscan.h> |
| 53 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 54 | struct scan_control { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 55 | /* Incremented by the number of inactive pages that were scanned */ |
| 56 | unsigned long nr_scanned; |
| 57 | |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 58 | /* Number of pages freed so far during a call to shrink_zones() */ |
| 59 | unsigned long nr_reclaimed; |
| 60 | |
KOSAKI Motohiro | 22fba33 | 2009-12-14 17:59:10 -0800 | [diff] [blame] | 61 | /* How many pages shrink_list() should reclaim */ |
| 62 | unsigned long nr_to_reclaim; |
| 63 | |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame] | 64 | unsigned long hibernation_mode; |
| 65 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 66 | /* This context's GFP mask */ |
Al Viro | 6daa0e2 | 2005-10-21 03:18:50 -0400 | [diff] [blame] | 67 | gfp_t gfp_mask; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 68 | |
| 69 | int may_writepage; |
| 70 | |
Johannes Weiner | a6dc60f8 | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 71 | /* Can mapped pages be reclaimed? */ |
| 72 | int may_unmap; |
Christoph Lameter | f1fd106 | 2006-01-18 17:42:30 -0800 | [diff] [blame] | 73 | |
KOSAKI Motohiro | 2e2e425 | 2009-04-21 12:24:57 -0700 | [diff] [blame] | 74 | /* Can pages be swapped as part of reclaim? */ |
| 75 | int may_swap; |
| 76 | |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 77 | int swappiness; |
Nick Piggin | 408d854 | 2006-09-25 23:31:27 -0700 | [diff] [blame] | 78 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 79 | int order; |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 80 | |
KOSAKI Motohiro | 5f53e76 | 2010-05-24 14:32:37 -0700 | [diff] [blame] | 81 | /* |
| 82 | * Intend to reclaim enough contenious memory rather than to reclaim |
| 83 | * enough amount memory. I.e, it's the mode for high order allocation. |
| 84 | */ |
| 85 | bool lumpy_reclaim_mode; |
| 86 | |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 87 | /* Which cgroup do we reclaim from */ |
| 88 | struct mem_cgroup *mem_cgroup; |
| 89 | |
KAMEZAWA Hiroyuki | 327c0e9 | 2009-03-31 15:23:31 -0700 | [diff] [blame] | 90 | /* |
| 91 | * Nodemask of nodes allowed by the caller. If NULL, all nodes |
| 92 | * are scanned. |
| 93 | */ |
| 94 | nodemask_t *nodemask; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 95 | }; |
| 96 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 97 | #define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru)) |
| 98 | |
| 99 | #ifdef ARCH_HAS_PREFETCH |
| 100 | #define prefetch_prev_lru_page(_page, _base, _field) \ |
| 101 | do { \ |
| 102 | if ((_page)->lru.prev != _base) { \ |
| 103 | struct page *prev; \ |
| 104 | \ |
| 105 | prev = lru_to_page(&(_page->lru)); \ |
| 106 | prefetch(&prev->_field); \ |
| 107 | } \ |
| 108 | } while (0) |
| 109 | #else |
| 110 | #define prefetch_prev_lru_page(_page, _base, _field) do { } while (0) |
| 111 | #endif |
| 112 | |
| 113 | #ifdef ARCH_HAS_PREFETCHW |
| 114 | #define prefetchw_prev_lru_page(_page, _base, _field) \ |
| 115 | do { \ |
| 116 | if ((_page)->lru.prev != _base) { \ |
| 117 | struct page *prev; \ |
| 118 | \ |
| 119 | prev = lru_to_page(&(_page->lru)); \ |
| 120 | prefetchw(&prev->_field); \ |
| 121 | } \ |
| 122 | } while (0) |
| 123 | #else |
| 124 | #define prefetchw_prev_lru_page(_page, _base, _field) do { } while (0) |
| 125 | #endif |
| 126 | |
| 127 | /* |
| 128 | * From 0 .. 100. Higher means more swappy. |
| 129 | */ |
| 130 | int vm_swappiness = 60; |
Andrew Morton | bd1e22b | 2006-06-23 02:03:47 -0700 | [diff] [blame] | 131 | 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] | 132 | |
| 133 | static LIST_HEAD(shrinker_list); |
| 134 | static DECLARE_RWSEM(shrinker_rwsem); |
| 135 | |
Balbir Singh | 00f0b82 | 2008-03-04 14:28:39 -0800 | [diff] [blame] | 136 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 137 | #define scanning_global_lru(sc) (!(sc)->mem_cgroup) |
KAMEZAWA Hiroyuki | 91a4547 | 2008-02-07 00:14:29 -0800 | [diff] [blame] | 138 | #else |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 139 | #define scanning_global_lru(sc) (1) |
KAMEZAWA Hiroyuki | 91a4547 | 2008-02-07 00:14:29 -0800 | [diff] [blame] | 140 | #endif |
| 141 | |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 142 | static struct zone_reclaim_stat *get_reclaim_stat(struct zone *zone, |
| 143 | struct scan_control *sc) |
| 144 | { |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 145 | if (!scanning_global_lru(sc)) |
KOSAKI Motohiro | 3e2f41f | 2009-01-07 18:08:20 -0800 | [diff] [blame] | 146 | return mem_cgroup_get_reclaim_stat(sc->mem_cgroup, zone); |
| 147 | |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 148 | return &zone->reclaim_stat; |
| 149 | } |
| 150 | |
Vincent Li | 0b21767 | 2009-09-21 17:03:09 -0700 | [diff] [blame] | 151 | static unsigned long zone_nr_lru_pages(struct zone *zone, |
| 152 | struct scan_control *sc, enum lru_list lru) |
KOSAKI Motohiro | c9f299d | 2009-01-07 18:08:16 -0800 | [diff] [blame] | 153 | { |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 154 | if (!scanning_global_lru(sc)) |
KOSAKI Motohiro | a3d8e05 | 2009-01-07 18:08:19 -0800 | [diff] [blame] | 155 | return mem_cgroup_zone_nr_pages(sc->mem_cgroup, zone, lru); |
| 156 | |
KOSAKI Motohiro | c9f299d | 2009-01-07 18:08:16 -0800 | [diff] [blame] | 157 | return zone_page_state(zone, NR_LRU_BASE + lru); |
| 158 | } |
| 159 | |
| 160 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 161 | /* |
| 162 | * Add a shrinker callback to be called from the vm |
| 163 | */ |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 164 | void register_shrinker(struct shrinker *shrinker) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 165 | { |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 166 | shrinker->nr = 0; |
| 167 | down_write(&shrinker_rwsem); |
| 168 | list_add_tail(&shrinker->list, &shrinker_list); |
| 169 | up_write(&shrinker_rwsem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 170 | } |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 171 | EXPORT_SYMBOL(register_shrinker); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 172 | |
| 173 | /* |
| 174 | * Remove one |
| 175 | */ |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 176 | void unregister_shrinker(struct shrinker *shrinker) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 177 | { |
| 178 | down_write(&shrinker_rwsem); |
| 179 | list_del(&shrinker->list); |
| 180 | up_write(&shrinker_rwsem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 181 | } |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 182 | EXPORT_SYMBOL(unregister_shrinker); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 183 | |
| 184 | #define SHRINK_BATCH 128 |
| 185 | /* |
| 186 | * Call the shrink functions to age shrinkable caches |
| 187 | * |
| 188 | * Here we assume it costs one seek to replace a lru page and that it also |
| 189 | * takes a seek to recreate a cache object. With this in mind we age equal |
| 190 | * percentages of the lru and ageable caches. This should balance the seeks |
| 191 | * generated by these structures. |
| 192 | * |
Simon Arlott | 183ff22 | 2007-10-20 01:27:18 +0200 | [diff] [blame] | 193 | * 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] | 194 | * slab to avoid swapping. |
| 195 | * |
| 196 | * We do weird things to avoid (scanned*seeks*entries) overflowing 32 bits. |
| 197 | * |
| 198 | * `lru_pages' represents the number of on-LRU pages in all the zones which |
| 199 | * are eligible for the caller's allocation attempt. It is used for balancing |
| 200 | * slab reclaim versus page reclaim. |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 201 | * |
| 202 | * Returns the number of slab objects which we shrunk. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 203 | */ |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 204 | unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask, |
| 205 | unsigned long lru_pages) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 206 | { |
| 207 | struct shrinker *shrinker; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 208 | unsigned long ret = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 209 | |
| 210 | if (scanned == 0) |
| 211 | scanned = SWAP_CLUSTER_MAX; |
| 212 | |
| 213 | if (!down_read_trylock(&shrinker_rwsem)) |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 214 | return 1; /* Assume we'll be able to shrink next time */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 215 | |
| 216 | list_for_each_entry(shrinker, &shrinker_list, list) { |
| 217 | unsigned long long delta; |
| 218 | unsigned long total_scan; |
Dave Chinner | 7f8275d | 2010-07-19 14:56:17 +1000 | [diff] [blame] | 219 | unsigned long max_pass; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 220 | |
Dave Chinner | 7f8275d | 2010-07-19 14:56:17 +1000 | [diff] [blame] | 221 | max_pass = (*shrinker->shrink)(shrinker, 0, gfp_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 222 | delta = (4 * scanned) / shrinker->seeks; |
Andrea Arcangeli | ea164d7 | 2005-11-28 13:44:15 -0800 | [diff] [blame] | 223 | delta *= max_pass; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 224 | do_div(delta, lru_pages + 1); |
| 225 | shrinker->nr += delta; |
Andrea Arcangeli | ea164d7 | 2005-11-28 13:44:15 -0800 | [diff] [blame] | 226 | if (shrinker->nr < 0) { |
David Rientjes | 88c3bd7 | 2009-03-31 15:23:29 -0700 | [diff] [blame] | 227 | printk(KERN_ERR "shrink_slab: %pF negative objects to " |
| 228 | "delete nr=%ld\n", |
| 229 | shrinker->shrink, shrinker->nr); |
Andrea Arcangeli | ea164d7 | 2005-11-28 13:44:15 -0800 | [diff] [blame] | 230 | shrinker->nr = max_pass; |
| 231 | } |
| 232 | |
| 233 | /* |
| 234 | * Avoid risking looping forever due to too large nr value: |
| 235 | * never try to free more than twice the estimate number of |
| 236 | * freeable entries. |
| 237 | */ |
| 238 | if (shrinker->nr > max_pass * 2) |
| 239 | shrinker->nr = max_pass * 2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 240 | |
| 241 | total_scan = shrinker->nr; |
| 242 | shrinker->nr = 0; |
| 243 | |
| 244 | while (total_scan >= SHRINK_BATCH) { |
| 245 | long this_scan = SHRINK_BATCH; |
| 246 | int shrink_ret; |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 247 | int nr_before; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 248 | |
Dave Chinner | 7f8275d | 2010-07-19 14:56:17 +1000 | [diff] [blame] | 249 | nr_before = (*shrinker->shrink)(shrinker, 0, gfp_mask); |
| 250 | shrink_ret = (*shrinker->shrink)(shrinker, this_scan, |
| 251 | gfp_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 252 | if (shrink_ret == -1) |
| 253 | break; |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 254 | if (shrink_ret < nr_before) |
| 255 | ret += nr_before - shrink_ret; |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 256 | count_vm_events(SLABS_SCANNED, this_scan); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 257 | total_scan -= this_scan; |
| 258 | |
| 259 | cond_resched(); |
| 260 | } |
| 261 | |
| 262 | shrinker->nr += total_scan; |
| 263 | } |
| 264 | up_read(&shrinker_rwsem); |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 265 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 266 | } |
| 267 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 268 | static inline int is_page_cache_freeable(struct page *page) |
| 269 | { |
Johannes Weiner | ceddc3a | 2009-09-21 17:03:00 -0700 | [diff] [blame] | 270 | /* |
| 271 | * A freeable page cache page is referenced only by the caller |
| 272 | * that isolated the page, the page cache radix tree and |
| 273 | * optional buffer heads at page->private. |
| 274 | */ |
Johannes Weiner | edcf474 | 2009-09-21 17:02:59 -0700 | [diff] [blame] | 275 | return page_count(page) - page_has_private(page) == 2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 276 | } |
| 277 | |
| 278 | static int may_write_to_queue(struct backing_dev_info *bdi) |
| 279 | { |
Christoph Lameter | 930d915 | 2006-01-08 01:00:47 -0800 | [diff] [blame] | 280 | if (current->flags & PF_SWAPWRITE) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 281 | return 1; |
| 282 | if (!bdi_write_congested(bdi)) |
| 283 | return 1; |
| 284 | if (bdi == current->backing_dev_info) |
| 285 | return 1; |
| 286 | return 0; |
| 287 | } |
| 288 | |
| 289 | /* |
| 290 | * We detected a synchronous write error writing a page out. Probably |
| 291 | * -ENOSPC. We need to propagate that into the address_space for a subsequent |
| 292 | * fsync(), msync() or close(). |
| 293 | * |
| 294 | * The tricky part is that after writepage we cannot touch the mapping: nothing |
| 295 | * prevents it from being freed up. But we have a ref on the page and once |
| 296 | * that page is locked, the mapping is pinned. |
| 297 | * |
| 298 | * We're allowed to run sleeping lock_page() here because we know the caller has |
| 299 | * __GFP_FS. |
| 300 | */ |
| 301 | static void handle_write_error(struct address_space *mapping, |
| 302 | struct page *page, int error) |
| 303 | { |
Nick Piggin | a6aa62a | 2010-07-20 13:24:25 -0700 | [diff] [blame] | 304 | lock_page_nosync(page); |
Guillaume Chazarain | 3e9f45b | 2007-05-08 00:23:25 -0700 | [diff] [blame] | 305 | if (page_mapping(page) == mapping) |
| 306 | mapping_set_error(mapping, error); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 307 | unlock_page(page); |
| 308 | } |
| 309 | |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 310 | /* Request for sync pageout. */ |
| 311 | enum pageout_io { |
| 312 | PAGEOUT_IO_ASYNC, |
| 313 | PAGEOUT_IO_SYNC, |
| 314 | }; |
| 315 | |
Christoph Lameter | 04e62a2 | 2006-06-23 02:03:38 -0700 | [diff] [blame] | 316 | /* possible outcome of pageout() */ |
| 317 | typedef enum { |
| 318 | /* failed to write page out, page is locked */ |
| 319 | PAGE_KEEP, |
| 320 | /* move page to the active list, page is locked */ |
| 321 | PAGE_ACTIVATE, |
| 322 | /* page has been sent to the disk successfully, page is unlocked */ |
| 323 | PAGE_SUCCESS, |
| 324 | /* page is clean and locked */ |
| 325 | PAGE_CLEAN, |
| 326 | } pageout_t; |
| 327 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 328 | /* |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 329 | * pageout is called by shrink_page_list() for each dirty page. |
| 330 | * Calls ->writepage(). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 331 | */ |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 332 | static pageout_t pageout(struct page *page, struct address_space *mapping, |
| 333 | enum pageout_io sync_writeback) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 334 | { |
| 335 | /* |
| 336 | * If the page is dirty, only perform writeback if that write |
| 337 | * will be non-blocking. To prevent this allocation from being |
| 338 | * stalled by pagecache activity. But note that there may be |
| 339 | * stalls if we need to run get_block(). We could test |
| 340 | * PagePrivate for that. |
| 341 | * |
Vincent Li | 6aceb53 | 2009-12-14 17:58:49 -0800 | [diff] [blame] | 342 | * If this process is currently in __generic_file_aio_write() against |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 343 | * this page's queue, we can perform writeback even if that |
| 344 | * will block. |
| 345 | * |
| 346 | * If the page is swapcache, write it back even if that would |
| 347 | * block, for some throttling. This happens by accident, because |
| 348 | * swap_backing_dev_info is bust: it doesn't reflect the |
| 349 | * congestion state of the swapdevs. Easy to fix, if needed. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 350 | */ |
| 351 | if (!is_page_cache_freeable(page)) |
| 352 | return PAGE_KEEP; |
| 353 | if (!mapping) { |
| 354 | /* |
| 355 | * Some data journaling orphaned pages can have |
| 356 | * page->mapping == NULL while being dirty with clean buffers. |
| 357 | */ |
David Howells | 266cf65 | 2009-04-03 16:42:36 +0100 | [diff] [blame] | 358 | if (page_has_private(page)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 359 | if (try_to_free_buffers(page)) { |
| 360 | ClearPageDirty(page); |
Harvey Harrison | d40cee2 | 2008-04-30 00:55:07 -0700 | [diff] [blame] | 361 | printk("%s: orphaned page\n", __func__); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 362 | return PAGE_CLEAN; |
| 363 | } |
| 364 | } |
| 365 | return PAGE_KEEP; |
| 366 | } |
| 367 | if (mapping->a_ops->writepage == NULL) |
| 368 | return PAGE_ACTIVATE; |
| 369 | if (!may_write_to_queue(mapping->backing_dev_info)) |
| 370 | return PAGE_KEEP; |
| 371 | |
| 372 | if (clear_page_dirty_for_io(page)) { |
| 373 | int res; |
| 374 | struct writeback_control wbc = { |
| 375 | .sync_mode = WB_SYNC_NONE, |
| 376 | .nr_to_write = SWAP_CLUSTER_MAX, |
OGAWA Hirofumi | 111ebb6 | 2006-06-23 02:03:26 -0700 | [diff] [blame] | 377 | .range_start = 0, |
| 378 | .range_end = LLONG_MAX, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 379 | .nonblocking = 1, |
| 380 | .for_reclaim = 1, |
| 381 | }; |
| 382 | |
| 383 | SetPageReclaim(page); |
| 384 | res = mapping->a_ops->writepage(page, &wbc); |
| 385 | if (res < 0) |
| 386 | handle_write_error(mapping, page, res); |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 387 | if (res == AOP_WRITEPAGE_ACTIVATE) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 388 | ClearPageReclaim(page); |
| 389 | return PAGE_ACTIVATE; |
| 390 | } |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 391 | |
| 392 | /* |
| 393 | * Wait on writeback if requested to. This happens when |
| 394 | * direct reclaiming a large contiguous area and the |
| 395 | * first attempt to free a range of pages fails. |
| 396 | */ |
| 397 | if (PageWriteback(page) && sync_writeback == PAGEOUT_IO_SYNC) |
| 398 | wait_on_page_writeback(page); |
| 399 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 400 | if (!PageWriteback(page)) { |
| 401 | /* synchronous write or broken a_ops? */ |
| 402 | ClearPageReclaim(page); |
| 403 | } |
Mel Gorman | 755f022 | 2010-08-09 17:19:18 -0700 | [diff] [blame] | 404 | trace_mm_vmscan_writepage(page, |
| 405 | trace_reclaim_flags(page, sync_writeback)); |
Andrew Morton | e129b5c | 2006-09-27 01:50:00 -0700 | [diff] [blame] | 406 | inc_zone_page_state(page, NR_VMSCAN_WRITE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 407 | return PAGE_SUCCESS; |
| 408 | } |
| 409 | |
| 410 | return PAGE_CLEAN; |
| 411 | } |
| 412 | |
Andrew Morton | a649fd9 | 2006-10-17 00:09:36 -0700 | [diff] [blame] | 413 | /* |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 414 | * Same as remove_mapping, but if the page is removed from the mapping, it |
| 415 | * gets returned with a refcount of 0. |
Andrew Morton | a649fd9 | 2006-10-17 00:09:36 -0700 | [diff] [blame] | 416 | */ |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 417 | static int __remove_mapping(struct address_space *mapping, struct page *page) |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 418 | { |
Nick Piggin | 28e4d96 | 2006-09-25 23:31:23 -0700 | [diff] [blame] | 419 | BUG_ON(!PageLocked(page)); |
| 420 | BUG_ON(mapping != page_mapping(page)); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 421 | |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 422 | spin_lock_irq(&mapping->tree_lock); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 423 | /* |
Nick Piggin | 0fd0e6b | 2006-09-27 01:50:02 -0700 | [diff] [blame] | 424 | * The non racy check for a busy page. |
| 425 | * |
| 426 | * Must be careful with the order of the tests. When someone has |
| 427 | * a ref to the page, it may be possible that they dirty it then |
| 428 | * drop the reference. So if PageDirty is tested before page_count |
| 429 | * here, then the following race may occur: |
| 430 | * |
| 431 | * get_user_pages(&page); |
| 432 | * [user mapping goes away] |
| 433 | * write_to(page); |
| 434 | * !PageDirty(page) [good] |
| 435 | * SetPageDirty(page); |
| 436 | * put_page(page); |
| 437 | * !page_count(page) [good, discard it] |
| 438 | * |
| 439 | * [oops, our write_to data is lost] |
| 440 | * |
| 441 | * Reversing the order of the tests ensures such a situation cannot |
| 442 | * escape unnoticed. The smp_rmb is needed to ensure the page->flags |
| 443 | * load is not satisfied before that of page->_count. |
| 444 | * |
| 445 | * Note that if SetPageDirty is always performed via set_page_dirty, |
| 446 | * and thus under tree_lock, then this ordering is not required. |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 447 | */ |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 448 | if (!page_freeze_refs(page, 2)) |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 449 | goto cannot_free; |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 450 | /* note: atomic_cmpxchg in page_freeze_refs provides the smp_rmb */ |
| 451 | if (unlikely(PageDirty(page))) { |
| 452 | page_unfreeze_refs(page, 2); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 453 | goto cannot_free; |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 454 | } |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 455 | |
| 456 | if (PageSwapCache(page)) { |
| 457 | swp_entry_t swap = { .val = page_private(page) }; |
| 458 | __delete_from_swap_cache(page); |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 459 | spin_unlock_irq(&mapping->tree_lock); |
KAMEZAWA Hiroyuki | cb4b86b | 2009-06-16 15:32:52 -0700 | [diff] [blame] | 460 | swapcache_free(swap, page); |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 461 | } else { |
| 462 | __remove_from_page_cache(page); |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 463 | spin_unlock_irq(&mapping->tree_lock); |
Daisuke Nishimura | e767e05 | 2009-05-28 14:34:28 -0700 | [diff] [blame] | 464 | mem_cgroup_uncharge_cache_page(page); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 465 | } |
| 466 | |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 467 | return 1; |
| 468 | |
| 469 | cannot_free: |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 470 | spin_unlock_irq(&mapping->tree_lock); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 471 | return 0; |
| 472 | } |
| 473 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 474 | /* |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 475 | * Attempt to detach a locked page from its ->mapping. If it is dirty or if |
| 476 | * someone else has a ref on the page, abort and return 0. If it was |
| 477 | * successfully detached, return 1. Assumes the caller has a single ref on |
| 478 | * this page. |
| 479 | */ |
| 480 | int remove_mapping(struct address_space *mapping, struct page *page) |
| 481 | { |
| 482 | if (__remove_mapping(mapping, page)) { |
| 483 | /* |
| 484 | * Unfreezing the refcount with 1 rather than 2 effectively |
| 485 | * drops the pagecache ref for us without requiring another |
| 486 | * atomic operation. |
| 487 | */ |
| 488 | page_unfreeze_refs(page, 1); |
| 489 | return 1; |
| 490 | } |
| 491 | return 0; |
| 492 | } |
| 493 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 494 | /** |
| 495 | * putback_lru_page - put previously isolated page onto appropriate LRU list |
| 496 | * @page: page to be put back to appropriate lru list |
| 497 | * |
| 498 | * Add previously isolated @page to appropriate LRU list. |
| 499 | * Page may still be unevictable for other reasons. |
| 500 | * |
| 501 | * lru_lock must not be held, interrupts must be enabled. |
| 502 | */ |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 503 | void putback_lru_page(struct page *page) |
| 504 | { |
| 505 | int lru; |
| 506 | int active = !!TestClearPageActive(page); |
Lee Schermerhorn | bbfd28e | 2008-10-18 20:26:40 -0700 | [diff] [blame] | 507 | int was_unevictable = PageUnevictable(page); |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 508 | |
| 509 | VM_BUG_ON(PageLRU(page)); |
| 510 | |
| 511 | redo: |
| 512 | ClearPageUnevictable(page); |
| 513 | |
| 514 | if (page_evictable(page, NULL)) { |
| 515 | /* |
| 516 | * For evictable pages, we can use the cache. |
| 517 | * In event of a race, worst case is we end up with an |
| 518 | * unevictable page on [in]active list. |
| 519 | * We know how to handle that. |
| 520 | */ |
Johannes Weiner | 401a8e1 | 2009-09-21 17:02:58 -0700 | [diff] [blame] | 521 | lru = active + page_lru_base_type(page); |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 522 | lru_cache_add_lru(page, lru); |
| 523 | } else { |
| 524 | /* |
| 525 | * Put unevictable pages directly on zone's unevictable |
| 526 | * list. |
| 527 | */ |
| 528 | lru = LRU_UNEVICTABLE; |
| 529 | add_page_to_unevictable_list(page); |
Johannes Weiner | 6a7b954 | 2009-10-26 16:50:00 -0700 | [diff] [blame] | 530 | /* |
| 531 | * When racing with an mlock clearing (page is |
| 532 | * unlocked), make sure that if the other thread does |
| 533 | * not observe our setting of PG_lru and fails |
| 534 | * isolation, we see PG_mlocked cleared below and move |
| 535 | * the page back to the evictable list. |
| 536 | * |
| 537 | * The other side is TestClearPageMlocked(). |
| 538 | */ |
| 539 | smp_mb(); |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 540 | } |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 541 | |
| 542 | /* |
| 543 | * page's status can change while we move it among lru. If an evictable |
| 544 | * page is on unevictable list, it never be freed. To avoid that, |
| 545 | * check after we added it to the list, again. |
| 546 | */ |
| 547 | if (lru == LRU_UNEVICTABLE && page_evictable(page, NULL)) { |
| 548 | if (!isolate_lru_page(page)) { |
| 549 | put_page(page); |
| 550 | goto redo; |
| 551 | } |
| 552 | /* This means someone else dropped this page from LRU |
| 553 | * So, it will be freed or putback to LRU again. There is |
| 554 | * nothing to do here. |
| 555 | */ |
| 556 | } |
| 557 | |
Lee Schermerhorn | bbfd28e | 2008-10-18 20:26:40 -0700 | [diff] [blame] | 558 | if (was_unevictable && lru != LRU_UNEVICTABLE) |
| 559 | count_vm_event(UNEVICTABLE_PGRESCUED); |
| 560 | else if (!was_unevictable && lru == LRU_UNEVICTABLE) |
| 561 | count_vm_event(UNEVICTABLE_PGCULLED); |
| 562 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 563 | put_page(page); /* drop ref from isolate */ |
| 564 | } |
| 565 | |
Johannes Weiner | dfc8d63 | 2010-03-05 13:42:19 -0800 | [diff] [blame] | 566 | enum page_references { |
| 567 | PAGEREF_RECLAIM, |
| 568 | PAGEREF_RECLAIM_CLEAN, |
Johannes Weiner | 64574746 | 2010-03-05 13:42:22 -0800 | [diff] [blame] | 569 | PAGEREF_KEEP, |
Johannes Weiner | dfc8d63 | 2010-03-05 13:42:19 -0800 | [diff] [blame] | 570 | PAGEREF_ACTIVATE, |
| 571 | }; |
| 572 | |
| 573 | static enum page_references page_check_references(struct page *page, |
| 574 | struct scan_control *sc) |
| 575 | { |
Johannes Weiner | 64574746 | 2010-03-05 13:42:22 -0800 | [diff] [blame] | 576 | int referenced_ptes, referenced_page; |
Johannes Weiner | dfc8d63 | 2010-03-05 13:42:19 -0800 | [diff] [blame] | 577 | unsigned long vm_flags; |
Johannes Weiner | dfc8d63 | 2010-03-05 13:42:19 -0800 | [diff] [blame] | 578 | |
Johannes Weiner | 64574746 | 2010-03-05 13:42:22 -0800 | [diff] [blame] | 579 | referenced_ptes = page_referenced(page, 1, sc->mem_cgroup, &vm_flags); |
| 580 | referenced_page = TestClearPageReferenced(page); |
Johannes Weiner | dfc8d63 | 2010-03-05 13:42:19 -0800 | [diff] [blame] | 581 | |
| 582 | /* Lumpy reclaim - ignore references */ |
KOSAKI Motohiro | 5f53e76 | 2010-05-24 14:32:37 -0700 | [diff] [blame] | 583 | if (sc->lumpy_reclaim_mode) |
Johannes Weiner | dfc8d63 | 2010-03-05 13:42:19 -0800 | [diff] [blame] | 584 | return PAGEREF_RECLAIM; |
| 585 | |
| 586 | /* |
| 587 | * Mlock lost the isolation race with us. Let try_to_unmap() |
| 588 | * move the page to the unevictable list. |
| 589 | */ |
| 590 | if (vm_flags & VM_LOCKED) |
| 591 | return PAGEREF_RECLAIM; |
| 592 | |
Johannes Weiner | 64574746 | 2010-03-05 13:42:22 -0800 | [diff] [blame] | 593 | if (referenced_ptes) { |
| 594 | if (PageAnon(page)) |
| 595 | return PAGEREF_ACTIVATE; |
| 596 | /* |
| 597 | * All mapped pages start out with page table |
| 598 | * references from the instantiating fault, so we need |
| 599 | * to look twice if a mapped file page is used more |
| 600 | * than once. |
| 601 | * |
| 602 | * Mark it and spare it for another trip around the |
| 603 | * inactive list. Another page table reference will |
| 604 | * lead to its activation. |
| 605 | * |
| 606 | * Note: the mark is set for activated pages as well |
| 607 | * so that recently deactivated but used pages are |
| 608 | * quickly recovered. |
| 609 | */ |
| 610 | SetPageReferenced(page); |
| 611 | |
| 612 | if (referenced_page) |
| 613 | return PAGEREF_ACTIVATE; |
| 614 | |
| 615 | return PAGEREF_KEEP; |
| 616 | } |
Johannes Weiner | dfc8d63 | 2010-03-05 13:42:19 -0800 | [diff] [blame] | 617 | |
| 618 | /* Reclaim if clean, defer dirty pages to writeback */ |
Johannes Weiner | 64574746 | 2010-03-05 13:42:22 -0800 | [diff] [blame] | 619 | if (referenced_page) |
| 620 | return PAGEREF_RECLAIM_CLEAN; |
| 621 | |
| 622 | return PAGEREF_RECLAIM; |
Johannes Weiner | dfc8d63 | 2010-03-05 13:42:19 -0800 | [diff] [blame] | 623 | } |
| 624 | |
Mel Gorman | abe4c3b | 2010-08-09 17:19:31 -0700 | [diff] [blame] | 625 | static noinline_for_stack void free_page_list(struct list_head *free_pages) |
| 626 | { |
| 627 | struct pagevec freed_pvec; |
| 628 | struct page *page, *tmp; |
| 629 | |
| 630 | pagevec_init(&freed_pvec, 1); |
| 631 | |
| 632 | list_for_each_entry_safe(page, tmp, free_pages, lru) { |
| 633 | list_del(&page->lru); |
| 634 | if (!pagevec_add(&freed_pvec, page)) { |
| 635 | __pagevec_free(&freed_pvec); |
| 636 | pagevec_reinit(&freed_pvec); |
| 637 | } |
| 638 | } |
| 639 | |
| 640 | pagevec_free(&freed_pvec); |
| 641 | } |
| 642 | |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 643 | /* |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 644 | * shrink_page_list() returns the number of reclaimed pages |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 645 | */ |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 646 | static unsigned long shrink_page_list(struct list_head *page_list, |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 647 | struct scan_control *sc, |
| 648 | enum pageout_io sync_writeback) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 649 | { |
| 650 | LIST_HEAD(ret_pages); |
Mel Gorman | abe4c3b | 2010-08-09 17:19:31 -0700 | [diff] [blame] | 651 | LIST_HEAD(free_pages); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 652 | int pgactivate = 0; |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 653 | unsigned long nr_reclaimed = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 654 | |
| 655 | cond_resched(); |
| 656 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 657 | while (!list_empty(page_list)) { |
Johannes Weiner | dfc8d63 | 2010-03-05 13:42:19 -0800 | [diff] [blame] | 658 | enum page_references references; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 659 | struct address_space *mapping; |
| 660 | struct page *page; |
| 661 | int may_enter_fs; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 662 | |
| 663 | cond_resched(); |
| 664 | |
| 665 | page = lru_to_page(page_list); |
| 666 | list_del(&page->lru); |
| 667 | |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 668 | if (!trylock_page(page)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 669 | goto keep; |
| 670 | |
Nick Piggin | 725d704 | 2006-09-25 23:30:55 -0700 | [diff] [blame] | 671 | VM_BUG_ON(PageActive(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 672 | |
| 673 | sc->nr_scanned++; |
Christoph Lameter | 80e4342 | 2006-02-11 17:55:53 -0800 | [diff] [blame] | 674 | |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 675 | if (unlikely(!page_evictable(page, NULL))) |
| 676 | goto cull_mlocked; |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 677 | |
Johannes Weiner | a6dc60f8 | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 678 | if (!sc->may_unmap && page_mapped(page)) |
Christoph Lameter | 80e4342 | 2006-02-11 17:55:53 -0800 | [diff] [blame] | 679 | goto keep_locked; |
| 680 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 681 | /* Double the slab pressure for mapped and swapcache pages */ |
| 682 | if (page_mapped(page) || PageSwapCache(page)) |
| 683 | sc->nr_scanned++; |
| 684 | |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 685 | may_enter_fs = (sc->gfp_mask & __GFP_FS) || |
| 686 | (PageSwapCache(page) && (sc->gfp_mask & __GFP_IO)); |
| 687 | |
| 688 | if (PageWriteback(page)) { |
| 689 | /* |
| 690 | * Synchronous reclaim is performed in two passes, |
| 691 | * first an asynchronous pass over the list to |
| 692 | * start parallel writeback, and a second synchronous |
| 693 | * pass to wait for the IO to complete. Wait here |
| 694 | * for any page for which writeback has already |
| 695 | * started. |
| 696 | */ |
| 697 | if (sync_writeback == PAGEOUT_IO_SYNC && may_enter_fs) |
| 698 | wait_on_page_writeback(page); |
Andrew Morton | 4dd4b92 | 2008-03-24 12:29:52 -0700 | [diff] [blame] | 699 | else |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 700 | goto keep_locked; |
| 701 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 702 | |
Johannes Weiner | dfc8d63 | 2010-03-05 13:42:19 -0800 | [diff] [blame] | 703 | references = page_check_references(page, sc); |
| 704 | switch (references) { |
| 705 | case PAGEREF_ACTIVATE: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 706 | goto activate_locked; |
Johannes Weiner | 64574746 | 2010-03-05 13:42:22 -0800 | [diff] [blame] | 707 | case PAGEREF_KEEP: |
| 708 | goto keep_locked; |
Johannes Weiner | dfc8d63 | 2010-03-05 13:42:19 -0800 | [diff] [blame] | 709 | case PAGEREF_RECLAIM: |
| 710 | case PAGEREF_RECLAIM_CLEAN: |
| 711 | ; /* try to reclaim the page below */ |
| 712 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 713 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 714 | /* |
| 715 | * Anonymous process memory has backing store? |
| 716 | * Try to allocate it some swap space here. |
| 717 | */ |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 718 | if (PageAnon(page) && !PageSwapCache(page)) { |
Hugh Dickins | 63eb6b9 | 2008-11-19 15:36:37 -0800 | [diff] [blame] | 719 | if (!(sc->gfp_mask & __GFP_IO)) |
| 720 | goto keep_locked; |
Hugh Dickins | ac47b00 | 2009-01-06 14:39:39 -0800 | [diff] [blame] | 721 | if (!add_to_swap(page)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 722 | goto activate_locked; |
Hugh Dickins | 63eb6b9 | 2008-11-19 15:36:37 -0800 | [diff] [blame] | 723 | may_enter_fs = 1; |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 724 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 725 | |
| 726 | mapping = page_mapping(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 727 | |
| 728 | /* |
| 729 | * The page is mapped into the page tables of one or more |
| 730 | * processes. Try to unmap it here. |
| 731 | */ |
| 732 | if (page_mapped(page) && mapping) { |
Andi Kleen | 14fa31b | 2009-09-16 11:50:10 +0200 | [diff] [blame] | 733 | switch (try_to_unmap(page, TTU_UNMAP)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 734 | case SWAP_FAIL: |
| 735 | goto activate_locked; |
| 736 | case SWAP_AGAIN: |
| 737 | goto keep_locked; |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 738 | case SWAP_MLOCK: |
| 739 | goto cull_mlocked; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 740 | case SWAP_SUCCESS: |
| 741 | ; /* try to free the page below */ |
| 742 | } |
| 743 | } |
| 744 | |
| 745 | if (PageDirty(page)) { |
Johannes Weiner | dfc8d63 | 2010-03-05 13:42:19 -0800 | [diff] [blame] | 746 | if (references == PAGEREF_RECLAIM_CLEAN) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 747 | goto keep_locked; |
Andrew Morton | 4dd4b92 | 2008-03-24 12:29:52 -0700 | [diff] [blame] | 748 | if (!may_enter_fs) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 749 | goto keep_locked; |
Christoph Lameter | 52a8363 | 2006-02-01 03:05:28 -0800 | [diff] [blame] | 750 | if (!sc->may_writepage) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 751 | goto keep_locked; |
| 752 | |
| 753 | /* Page is dirty, try to write it out here */ |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 754 | switch (pageout(page, mapping, sync_writeback)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 755 | case PAGE_KEEP: |
| 756 | goto keep_locked; |
| 757 | case PAGE_ACTIVATE: |
| 758 | goto activate_locked; |
| 759 | case PAGE_SUCCESS: |
Andrew Morton | 4dd4b92 | 2008-03-24 12:29:52 -0700 | [diff] [blame] | 760 | if (PageWriteback(page) || PageDirty(page)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 761 | goto keep; |
| 762 | /* |
| 763 | * A synchronous write - probably a ramdisk. Go |
| 764 | * ahead and try to reclaim the page. |
| 765 | */ |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 766 | if (!trylock_page(page)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 767 | goto keep; |
| 768 | if (PageDirty(page) || PageWriteback(page)) |
| 769 | goto keep_locked; |
| 770 | mapping = page_mapping(page); |
| 771 | case PAGE_CLEAN: |
| 772 | ; /* try to free the page below */ |
| 773 | } |
| 774 | } |
| 775 | |
| 776 | /* |
| 777 | * If the page has buffers, try to free the buffer mappings |
| 778 | * associated with this page. If we succeed we try to free |
| 779 | * the page as well. |
| 780 | * |
| 781 | * We do this even if the page is PageDirty(). |
| 782 | * try_to_release_page() does not perform I/O, but it is |
| 783 | * possible for a page to have PageDirty set, but it is actually |
| 784 | * clean (all its buffers are clean). This happens if the |
| 785 | * buffers were written out directly, with submit_bh(). ext3 |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 786 | * will do this, as well as the blockdev mapping. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 787 | * try_to_release_page() will discover that cleanness and will |
| 788 | * drop the buffers and mark the page clean - it can be freed. |
| 789 | * |
| 790 | * Rarely, pages can have buffers and no ->mapping. These are |
| 791 | * the pages which were not successfully invalidated in |
| 792 | * truncate_complete_page(). We try to drop those buffers here |
| 793 | * and if that worked, and the page is no longer mapped into |
| 794 | * process address space (page_count == 1) it can be freed. |
| 795 | * Otherwise, leave the page on the LRU so it is swappable. |
| 796 | */ |
David Howells | 266cf65 | 2009-04-03 16:42:36 +0100 | [diff] [blame] | 797 | if (page_has_private(page)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 798 | if (!try_to_release_page(page, sc->gfp_mask)) |
| 799 | goto activate_locked; |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 800 | if (!mapping && page_count(page) == 1) { |
| 801 | unlock_page(page); |
| 802 | if (put_page_testzero(page)) |
| 803 | goto free_it; |
| 804 | else { |
| 805 | /* |
| 806 | * rare race with speculative reference. |
| 807 | * the speculative reference will free |
| 808 | * this page shortly, so we may |
| 809 | * increment nr_reclaimed here (and |
| 810 | * leave it off the LRU). |
| 811 | */ |
| 812 | nr_reclaimed++; |
| 813 | continue; |
| 814 | } |
| 815 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 816 | } |
| 817 | |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 818 | if (!mapping || !__remove_mapping(mapping, page)) |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 819 | goto keep_locked; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 820 | |
Nick Piggin | a978d6f | 2008-10-18 20:26:58 -0700 | [diff] [blame] | 821 | /* |
| 822 | * At this point, we have no other references and there is |
| 823 | * no way to pick any more up (removed from LRU, removed |
| 824 | * from pagecache). Can use non-atomic bitops now (and |
| 825 | * we obviously don't have to worry about waking up a process |
| 826 | * waiting on the page lock, because there are no references. |
| 827 | */ |
| 828 | __clear_page_locked(page); |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 829 | free_it: |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 830 | nr_reclaimed++; |
Mel Gorman | abe4c3b | 2010-08-09 17:19:31 -0700 | [diff] [blame] | 831 | |
| 832 | /* |
| 833 | * Is there need to periodically free_page_list? It would |
| 834 | * appear not as the counts should be low |
| 835 | */ |
| 836 | list_add(&page->lru, &free_pages); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 837 | continue; |
| 838 | |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 839 | cull_mlocked: |
Hugh Dickins | 63d6c5a | 2009-01-06 14:39:38 -0800 | [diff] [blame] | 840 | if (PageSwapCache(page)) |
| 841 | try_to_free_swap(page); |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 842 | unlock_page(page); |
| 843 | putback_lru_page(page); |
| 844 | continue; |
| 845 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 846 | activate_locked: |
Rik van Riel | 68a22394 | 2008-10-18 20:26:23 -0700 | [diff] [blame] | 847 | /* Not a candidate for swapping, so reclaim swap space. */ |
| 848 | if (PageSwapCache(page) && vm_swap_full()) |
Hugh Dickins | a2c43ee | 2009-01-06 14:39:36 -0800 | [diff] [blame] | 849 | try_to_free_swap(page); |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 850 | VM_BUG_ON(PageActive(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 851 | SetPageActive(page); |
| 852 | pgactivate++; |
| 853 | keep_locked: |
| 854 | unlock_page(page); |
| 855 | keep: |
| 856 | list_add(&page->lru, &ret_pages); |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 857 | VM_BUG_ON(PageLRU(page) || PageUnevictable(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 858 | } |
Mel Gorman | abe4c3b | 2010-08-09 17:19:31 -0700 | [diff] [blame] | 859 | |
| 860 | free_page_list(&free_pages); |
| 861 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 862 | list_splice(&ret_pages, page_list); |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 863 | count_vm_events(PGACTIVATE, pgactivate); |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 864 | return nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 865 | } |
| 866 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 867 | /* |
| 868 | * Attempt to remove the specified page from its LRU. Only take this page |
| 869 | * if it is of the appropriate PageActive status. Pages which are being |
| 870 | * freed elsewhere are also ignored. |
| 871 | * |
| 872 | * page: page to consider |
| 873 | * mode: one of the LRU isolation modes defined above |
| 874 | * |
| 875 | * returns 0 on success, -ve errno on failure. |
| 876 | */ |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 877 | int __isolate_lru_page(struct page *page, int mode, int file) |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 878 | { |
| 879 | int ret = -EINVAL; |
| 880 | |
| 881 | /* Only take pages on the LRU. */ |
| 882 | if (!PageLRU(page)) |
| 883 | return ret; |
| 884 | |
| 885 | /* |
| 886 | * When checking the active state, we need to be sure we are |
| 887 | * dealing with comparible boolean values. Take the logical not |
| 888 | * of each. |
| 889 | */ |
| 890 | if (mode != ISOLATE_BOTH && (!PageActive(page) != !mode)) |
| 891 | return ret; |
| 892 | |
Johannes Weiner | 6c0b135 | 2009-09-21 17:02:59 -0700 | [diff] [blame] | 893 | if (mode != ISOLATE_BOTH && page_is_file_cache(page) != file) |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 894 | return ret; |
| 895 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 896 | /* |
| 897 | * When this function is being called for lumpy reclaim, we |
| 898 | * initially look into all LRU pages, active, inactive and |
| 899 | * unevictable; only give shrink_page_list evictable pages. |
| 900 | */ |
| 901 | if (PageUnevictable(page)) |
| 902 | return ret; |
| 903 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 904 | ret = -EBUSY; |
KAMEZAWA Hiroyuki | 08e552c | 2009-01-07 18:08:01 -0800 | [diff] [blame] | 905 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 906 | if (likely(get_page_unless_zero(page))) { |
| 907 | /* |
| 908 | * Be careful not to clear PageLRU until after we're |
| 909 | * sure the page is not being freed elsewhere -- the |
| 910 | * page release code relies on it. |
| 911 | */ |
| 912 | ClearPageLRU(page); |
| 913 | ret = 0; |
| 914 | } |
| 915 | |
| 916 | return ret; |
| 917 | } |
| 918 | |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 919 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 920 | * zone->lru_lock is heavily contended. Some of the functions that |
| 921 | * shrink the lists perform better by taking out a batch of pages |
| 922 | * and working on them outside the LRU lock. |
| 923 | * |
| 924 | * For pagecache intensive workloads, this function is the hottest |
| 925 | * spot in the kernel (apart from copy_*_user functions). |
| 926 | * |
| 927 | * Appropriate locks must be held before calling this function. |
| 928 | * |
| 929 | * @nr_to_scan: The number of pages to look through on the list. |
| 930 | * @src: The LRU list to pull pages off. |
| 931 | * @dst: The temp list to put pages on to. |
| 932 | * @scanned: The number of pages that were scanned. |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 933 | * @order: The caller's attempted allocation order |
| 934 | * @mode: One of the LRU isolation modes |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 935 | * @file: True [1] if isolating file [!anon] pages |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 936 | * |
| 937 | * returns how many pages were moved onto *@dst. |
| 938 | */ |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 939 | static unsigned long isolate_lru_pages(unsigned long nr_to_scan, |
| 940 | struct list_head *src, struct list_head *dst, |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 941 | unsigned long *scanned, int order, int mode, int file) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 942 | { |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 943 | unsigned long nr_taken = 0; |
Mel Gorman | a8a94d1 | 2010-08-09 17:19:17 -0700 | [diff] [blame] | 944 | unsigned long nr_lumpy_taken = 0; |
| 945 | unsigned long nr_lumpy_dirty = 0; |
| 946 | unsigned long nr_lumpy_failed = 0; |
Wu Fengguang | c9b02d9 | 2006-03-22 00:08:23 -0800 | [diff] [blame] | 947 | unsigned long scan; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 948 | |
Wu Fengguang | c9b02d9 | 2006-03-22 00:08:23 -0800 | [diff] [blame] | 949 | for (scan = 0; scan < nr_to_scan && !list_empty(src); scan++) { |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 950 | struct page *page; |
| 951 | unsigned long pfn; |
| 952 | unsigned long end_pfn; |
| 953 | unsigned long page_pfn; |
| 954 | int zone_id; |
| 955 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 956 | page = lru_to_page(src); |
| 957 | prefetchw_prev_lru_page(page, src, flags); |
| 958 | |
Nick Piggin | 725d704 | 2006-09-25 23:30:55 -0700 | [diff] [blame] | 959 | VM_BUG_ON(!PageLRU(page)); |
Nick Piggin | 8d438f9 | 2006-03-22 00:07:59 -0800 | [diff] [blame] | 960 | |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 961 | switch (__isolate_lru_page(page, mode, file)) { |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 962 | case 0: |
| 963 | list_move(&page->lru, dst); |
KAMEZAWA Hiroyuki | 2ffebca | 2009-06-17 16:27:21 -0700 | [diff] [blame] | 964 | mem_cgroup_del_lru(page); |
Nick Piggin | 7c8ee9a | 2006-03-22 00:08:03 -0800 | [diff] [blame] | 965 | nr_taken++; |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 966 | break; |
Nick Piggin | 46453a6 | 2006-03-22 00:07:58 -0800 | [diff] [blame] | 967 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 968 | case -EBUSY: |
| 969 | /* else it is being freed elsewhere */ |
| 970 | list_move(&page->lru, src); |
KAMEZAWA Hiroyuki | 2ffebca | 2009-06-17 16:27:21 -0700 | [diff] [blame] | 971 | mem_cgroup_rotate_lru_list(page, page_lru(page)); |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 972 | continue; |
| 973 | |
| 974 | default: |
| 975 | BUG(); |
| 976 | } |
| 977 | |
| 978 | if (!order) |
| 979 | continue; |
| 980 | |
| 981 | /* |
| 982 | * Attempt to take all pages in the order aligned region |
| 983 | * surrounding the tag page. Only take those pages of |
| 984 | * the same active state as that tag page. We may safely |
| 985 | * round the target page pfn down to the requested order |
| 986 | * as the mem_map is guarenteed valid out to MAX_ORDER, |
| 987 | * where that page is in a different zone we will detect |
| 988 | * it from its zone id and abort this block scan. |
| 989 | */ |
| 990 | zone_id = page_zone_id(page); |
| 991 | page_pfn = page_to_pfn(page); |
| 992 | pfn = page_pfn & ~((1 << order) - 1); |
| 993 | end_pfn = pfn + (1 << order); |
| 994 | for (; pfn < end_pfn; pfn++) { |
| 995 | struct page *cursor_page; |
| 996 | |
| 997 | /* The target page is in the block, ignore it. */ |
| 998 | if (unlikely(pfn == page_pfn)) |
| 999 | continue; |
| 1000 | |
| 1001 | /* Avoid holes within the zone. */ |
| 1002 | if (unlikely(!pfn_valid_within(pfn))) |
| 1003 | break; |
| 1004 | |
| 1005 | cursor_page = pfn_to_page(pfn); |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1006 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1007 | /* Check that we have not crossed a zone boundary. */ |
| 1008 | if (unlikely(page_zone_id(cursor_page) != zone_id)) |
| 1009 | continue; |
Minchan Kim | de2e756 | 2009-09-21 17:01:43 -0700 | [diff] [blame] | 1010 | |
| 1011 | /* |
| 1012 | * If we don't have enough swap space, reclaiming of |
| 1013 | * anon page which don't already have a swap slot is |
| 1014 | * pointless. |
| 1015 | */ |
| 1016 | if (nr_swap_pages <= 0 && PageAnon(cursor_page) && |
| 1017 | !PageSwapCache(cursor_page)) |
| 1018 | continue; |
| 1019 | |
KAMEZAWA Hiroyuki | ee993b1 | 2009-06-16 15:33:24 -0700 | [diff] [blame] | 1020 | if (__isolate_lru_page(cursor_page, mode, file) == 0) { |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1021 | list_move(&cursor_page->lru, dst); |
KAMEZAWA Hiroyuki | cb4cbcf | 2009-06-23 08:57:55 +0900 | [diff] [blame] | 1022 | mem_cgroup_del_lru(cursor_page); |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1023 | nr_taken++; |
Mel Gorman | a8a94d1 | 2010-08-09 17:19:17 -0700 | [diff] [blame] | 1024 | nr_lumpy_taken++; |
| 1025 | if (PageDirty(cursor_page)) |
| 1026 | nr_lumpy_dirty++; |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1027 | scan++; |
Mel Gorman | a8a94d1 | 2010-08-09 17:19:17 -0700 | [diff] [blame] | 1028 | } else { |
| 1029 | if (mode == ISOLATE_BOTH && |
| 1030 | page_count(cursor_page)) |
| 1031 | nr_lumpy_failed++; |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1032 | } |
| 1033 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1034 | } |
| 1035 | |
| 1036 | *scanned = scan; |
Mel Gorman | a8a94d1 | 2010-08-09 17:19:17 -0700 | [diff] [blame] | 1037 | |
| 1038 | trace_mm_vmscan_lru_isolate(order, |
| 1039 | nr_to_scan, scan, |
| 1040 | nr_taken, |
| 1041 | nr_lumpy_taken, nr_lumpy_dirty, nr_lumpy_failed, |
| 1042 | mode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1043 | return nr_taken; |
| 1044 | } |
| 1045 | |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1046 | static unsigned long isolate_pages_global(unsigned long nr, |
| 1047 | struct list_head *dst, |
| 1048 | unsigned long *scanned, int order, |
| 1049 | int mode, struct zone *z, |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1050 | int active, int file) |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1051 | { |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1052 | int lru = LRU_BASE; |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1053 | if (active) |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1054 | lru += LRU_ACTIVE; |
| 1055 | if (file) |
| 1056 | lru += LRU_FILE; |
| 1057 | return isolate_lru_pages(nr, &z->lru[lru].list, dst, scanned, order, |
Johannes Weiner | b7c46d1 | 2009-09-21 17:02:56 -0700 | [diff] [blame] | 1058 | mode, file); |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1059 | } |
| 1060 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1061 | /* |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1062 | * clear_active_flags() is a helper for shrink_active_list(), clearing |
| 1063 | * any active bits from the pages in the list. |
| 1064 | */ |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1065 | static unsigned long clear_active_flags(struct list_head *page_list, |
| 1066 | unsigned int *count) |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1067 | { |
| 1068 | int nr_active = 0; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1069 | int lru; |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1070 | struct page *page; |
| 1071 | |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1072 | list_for_each_entry(page, page_list, lru) { |
Johannes Weiner | 401a8e1 | 2009-09-21 17:02:58 -0700 | [diff] [blame] | 1073 | lru = page_lru_base_type(page); |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1074 | if (PageActive(page)) { |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1075 | lru += LRU_ACTIVE; |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1076 | ClearPageActive(page); |
| 1077 | nr_active++; |
| 1078 | } |
Mel Gorman | 1489fa1 | 2010-08-09 17:19:33 -0700 | [diff] [blame] | 1079 | if (count) |
| 1080 | count[lru]++; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1081 | } |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1082 | |
| 1083 | return nr_active; |
| 1084 | } |
| 1085 | |
Nick Piggin | 62695a8 | 2008-10-18 20:26:09 -0700 | [diff] [blame] | 1086 | /** |
| 1087 | * isolate_lru_page - tries to isolate a page from its LRU list |
| 1088 | * @page: page to isolate from its LRU list |
| 1089 | * |
| 1090 | * Isolates a @page from an LRU list, clears PageLRU and adjusts the |
| 1091 | * vmstat statistic corresponding to whatever LRU list the page was on. |
| 1092 | * |
| 1093 | * Returns 0 if the page was removed from an LRU list. |
| 1094 | * Returns -EBUSY if the page was not on an LRU list. |
| 1095 | * |
| 1096 | * The returned page will have PageLRU() cleared. If it was found on |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 1097 | * the active list, it will have PageActive set. If it was found on |
| 1098 | * the unevictable list, it will have the PageUnevictable bit set. That flag |
| 1099 | * 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] | 1100 | * |
| 1101 | * The vmstat statistic corresponding to the list on which the page was |
| 1102 | * found will be decremented. |
| 1103 | * |
| 1104 | * Restrictions: |
| 1105 | * (1) Must be called with an elevated refcount on the page. This is a |
| 1106 | * fundamentnal difference from isolate_lru_pages (which is called |
| 1107 | * without a stable reference). |
| 1108 | * (2) the lru_lock must not be held. |
| 1109 | * (3) interrupts must be enabled. |
| 1110 | */ |
| 1111 | int isolate_lru_page(struct page *page) |
| 1112 | { |
| 1113 | int ret = -EBUSY; |
| 1114 | |
| 1115 | if (PageLRU(page)) { |
| 1116 | struct zone *zone = page_zone(page); |
| 1117 | |
| 1118 | spin_lock_irq(&zone->lru_lock); |
| 1119 | if (PageLRU(page) && get_page_unless_zero(page)) { |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 1120 | int lru = page_lru(page); |
Nick Piggin | 62695a8 | 2008-10-18 20:26:09 -0700 | [diff] [blame] | 1121 | ret = 0; |
| 1122 | ClearPageLRU(page); |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1123 | |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1124 | del_page_from_lru_list(zone, page, lru); |
Nick Piggin | 62695a8 | 2008-10-18 20:26:09 -0700 | [diff] [blame] | 1125 | } |
| 1126 | spin_unlock_irq(&zone->lru_lock); |
| 1127 | } |
| 1128 | return ret; |
| 1129 | } |
| 1130 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1131 | /* |
Rik van Riel | 35cd781 | 2009-09-21 17:01:38 -0700 | [diff] [blame] | 1132 | * Are there way too many processes in the direct reclaim path already? |
| 1133 | */ |
| 1134 | static int too_many_isolated(struct zone *zone, int file, |
| 1135 | struct scan_control *sc) |
| 1136 | { |
| 1137 | unsigned long inactive, isolated; |
| 1138 | |
| 1139 | if (current_is_kswapd()) |
| 1140 | return 0; |
| 1141 | |
| 1142 | if (!scanning_global_lru(sc)) |
| 1143 | return 0; |
| 1144 | |
| 1145 | if (file) { |
| 1146 | inactive = zone_page_state(zone, NR_INACTIVE_FILE); |
| 1147 | isolated = zone_page_state(zone, NR_ISOLATED_FILE); |
| 1148 | } else { |
| 1149 | inactive = zone_page_state(zone, NR_INACTIVE_ANON); |
| 1150 | isolated = zone_page_state(zone, NR_ISOLATED_ANON); |
| 1151 | } |
| 1152 | |
| 1153 | return isolated > inactive; |
| 1154 | } |
| 1155 | |
| 1156 | /* |
Mel Gorman | 6663562 | 2010-08-09 17:19:30 -0700 | [diff] [blame] | 1157 | * TODO: Try merging with migrations version of putback_lru_pages |
| 1158 | */ |
| 1159 | static noinline_for_stack void |
Mel Gorman | 1489fa1 | 2010-08-09 17:19:33 -0700 | [diff] [blame] | 1160 | putback_lru_pages(struct zone *zone, struct scan_control *sc, |
Mel Gorman | 6663562 | 2010-08-09 17:19:30 -0700 | [diff] [blame] | 1161 | unsigned long nr_anon, unsigned long nr_file, |
| 1162 | struct list_head *page_list) |
| 1163 | { |
| 1164 | struct page *page; |
| 1165 | struct pagevec pvec; |
Mel Gorman | 1489fa1 | 2010-08-09 17:19:33 -0700 | [diff] [blame] | 1166 | struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc); |
Mel Gorman | 6663562 | 2010-08-09 17:19:30 -0700 | [diff] [blame] | 1167 | |
| 1168 | pagevec_init(&pvec, 1); |
| 1169 | |
| 1170 | /* |
| 1171 | * Put back any unfreeable pages. |
| 1172 | */ |
| 1173 | spin_lock(&zone->lru_lock); |
| 1174 | while (!list_empty(page_list)) { |
| 1175 | int lru; |
| 1176 | page = lru_to_page(page_list); |
| 1177 | VM_BUG_ON(PageLRU(page)); |
| 1178 | list_del(&page->lru); |
| 1179 | if (unlikely(!page_evictable(page, NULL))) { |
| 1180 | spin_unlock_irq(&zone->lru_lock); |
| 1181 | putback_lru_page(page); |
| 1182 | spin_lock_irq(&zone->lru_lock); |
| 1183 | continue; |
| 1184 | } |
| 1185 | SetPageLRU(page); |
| 1186 | lru = page_lru(page); |
| 1187 | add_page_to_lru_list(zone, page, lru); |
| 1188 | if (is_active_lru(lru)) { |
| 1189 | int file = is_file_lru(lru); |
| 1190 | reclaim_stat->recent_rotated[file]++; |
| 1191 | } |
| 1192 | if (!pagevec_add(&pvec, page)) { |
| 1193 | spin_unlock_irq(&zone->lru_lock); |
| 1194 | __pagevec_release(&pvec); |
| 1195 | spin_lock_irq(&zone->lru_lock); |
| 1196 | } |
| 1197 | } |
| 1198 | __mod_zone_page_state(zone, NR_ISOLATED_ANON, -nr_anon); |
| 1199 | __mod_zone_page_state(zone, NR_ISOLATED_FILE, -nr_file); |
| 1200 | |
| 1201 | spin_unlock_irq(&zone->lru_lock); |
| 1202 | pagevec_release(&pvec); |
| 1203 | } |
| 1204 | |
Mel Gorman | 1489fa1 | 2010-08-09 17:19:33 -0700 | [diff] [blame] | 1205 | static noinline_for_stack void update_isolated_counts(struct zone *zone, |
| 1206 | struct scan_control *sc, |
| 1207 | unsigned long *nr_anon, |
| 1208 | unsigned long *nr_file, |
| 1209 | struct list_head *isolated_list) |
| 1210 | { |
| 1211 | unsigned long nr_active; |
| 1212 | unsigned int count[NR_LRU_LISTS] = { 0, }; |
| 1213 | struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc); |
| 1214 | |
| 1215 | nr_active = clear_active_flags(isolated_list, count); |
| 1216 | __count_vm_events(PGDEACTIVATE, nr_active); |
| 1217 | |
| 1218 | __mod_zone_page_state(zone, NR_ACTIVE_FILE, |
| 1219 | -count[LRU_ACTIVE_FILE]); |
| 1220 | __mod_zone_page_state(zone, NR_INACTIVE_FILE, |
| 1221 | -count[LRU_INACTIVE_FILE]); |
| 1222 | __mod_zone_page_state(zone, NR_ACTIVE_ANON, |
| 1223 | -count[LRU_ACTIVE_ANON]); |
| 1224 | __mod_zone_page_state(zone, NR_INACTIVE_ANON, |
| 1225 | -count[LRU_INACTIVE_ANON]); |
| 1226 | |
| 1227 | *nr_anon = count[LRU_ACTIVE_ANON] + count[LRU_INACTIVE_ANON]; |
| 1228 | *nr_file = count[LRU_ACTIVE_FILE] + count[LRU_INACTIVE_FILE]; |
| 1229 | __mod_zone_page_state(zone, NR_ISOLATED_ANON, *nr_anon); |
| 1230 | __mod_zone_page_state(zone, NR_ISOLATED_FILE, *nr_file); |
| 1231 | |
| 1232 | reclaim_stat->recent_scanned[0] += *nr_anon; |
| 1233 | reclaim_stat->recent_scanned[1] += *nr_file; |
| 1234 | } |
| 1235 | |
Mel Gorman | 6663562 | 2010-08-09 17:19:30 -0700 | [diff] [blame] | 1236 | /* |
Wu Fengguang | e31f3698 | 2010-08-09 17:20:01 -0700 | [diff] [blame] | 1237 | * Returns true if the caller should wait to clean dirty/writeback pages. |
| 1238 | * |
| 1239 | * If we are direct reclaiming for contiguous pages and we do not reclaim |
| 1240 | * everything in the list, try again and wait for writeback IO to complete. |
| 1241 | * This will stall high-order allocations noticeably. Only do that when really |
| 1242 | * need to free the pages under high memory pressure. |
| 1243 | */ |
| 1244 | static inline bool should_reclaim_stall(unsigned long nr_taken, |
| 1245 | unsigned long nr_freed, |
| 1246 | int priority, |
| 1247 | struct scan_control *sc) |
| 1248 | { |
| 1249 | int lumpy_stall_priority; |
| 1250 | |
| 1251 | /* kswapd should not stall on sync IO */ |
| 1252 | if (current_is_kswapd()) |
| 1253 | return false; |
| 1254 | |
| 1255 | /* Only stall on lumpy reclaim */ |
| 1256 | if (!sc->lumpy_reclaim_mode) |
| 1257 | return false; |
| 1258 | |
| 1259 | /* If we have relaimed everything on the isolated list, no stall */ |
| 1260 | if (nr_freed == nr_taken) |
| 1261 | return false; |
| 1262 | |
| 1263 | /* |
| 1264 | * For high-order allocations, there are two stall thresholds. |
| 1265 | * High-cost allocations stall immediately where as lower |
| 1266 | * order allocations such as stacks require the scanning |
| 1267 | * priority to be much higher before stalling. |
| 1268 | */ |
| 1269 | if (sc->order > PAGE_ALLOC_COSTLY_ORDER) |
| 1270 | lumpy_stall_priority = DEF_PRIORITY; |
| 1271 | else |
| 1272 | lumpy_stall_priority = DEF_PRIORITY / 3; |
| 1273 | |
| 1274 | return priority <= lumpy_stall_priority; |
| 1275 | } |
| 1276 | |
| 1277 | /* |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 1278 | * shrink_inactive_list() is a helper for shrink_zone(). It returns the number |
| 1279 | * of reclaimed pages |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1280 | */ |
Mel Gorman | 6663562 | 2010-08-09 17:19:30 -0700 | [diff] [blame] | 1281 | static noinline_for_stack unsigned long |
| 1282 | shrink_inactive_list(unsigned long nr_to_scan, struct zone *zone, |
| 1283 | struct scan_control *sc, int priority, int file) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1284 | { |
| 1285 | LIST_HEAD(page_list); |
KOSAKI Motohiro | e247dbc | 2010-08-09 17:19:28 -0700 | [diff] [blame] | 1286 | unsigned long nr_scanned; |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1287 | unsigned long nr_reclaimed = 0; |
KOSAKI Motohiro | e247dbc | 2010-08-09 17:19:28 -0700 | [diff] [blame] | 1288 | unsigned long nr_taken; |
| 1289 | unsigned long nr_active; |
KOSAKI Motohiro | e247dbc | 2010-08-09 17:19:28 -0700 | [diff] [blame] | 1290 | unsigned long nr_anon; |
| 1291 | unsigned long nr_file; |
KOSAKI Motohiro | 78dc583 | 2009-06-16 15:31:40 -0700 | [diff] [blame] | 1292 | |
Rik van Riel | 35cd781 | 2009-09-21 17:01:38 -0700 | [diff] [blame] | 1293 | while (unlikely(too_many_isolated(zone, file, sc))) { |
KOSAKI Motohiro | 58355c7 | 2009-10-26 16:49:35 -0700 | [diff] [blame] | 1294 | congestion_wait(BLK_RW_ASYNC, HZ/10); |
Rik van Riel | 35cd781 | 2009-09-21 17:01:38 -0700 | [diff] [blame] | 1295 | |
| 1296 | /* We are about to die and free our memory. Return now. */ |
| 1297 | if (fatal_signal_pending(current)) |
| 1298 | return SWAP_CLUSTER_MAX; |
| 1299 | } |
| 1300 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1301 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1302 | lru_add_drain(); |
| 1303 | spin_lock_irq(&zone->lru_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1304 | |
KOSAKI Motohiro | e247dbc | 2010-08-09 17:19:28 -0700 | [diff] [blame] | 1305 | if (scanning_global_lru(sc)) { |
| 1306 | nr_taken = isolate_pages_global(nr_to_scan, |
| 1307 | &page_list, &nr_scanned, sc->order, |
| 1308 | sc->lumpy_reclaim_mode ? |
| 1309 | ISOLATE_BOTH : ISOLATE_INACTIVE, |
| 1310 | zone, 0, file); |
| 1311 | zone->pages_scanned += nr_scanned; |
KOSAKI Motohiro | b35ea17 | 2009-09-21 17:01:36 -0700 | [diff] [blame] | 1312 | if (current_is_kswapd()) |
KOSAKI Motohiro | e247dbc | 2010-08-09 17:19:28 -0700 | [diff] [blame] | 1313 | __count_zone_vm_events(PGSCAN_KSWAPD, zone, |
| 1314 | nr_scanned); |
| 1315 | else |
| 1316 | __count_zone_vm_events(PGSCAN_DIRECT, zone, |
| 1317 | nr_scanned); |
| 1318 | } else { |
| 1319 | nr_taken = mem_cgroup_isolate_pages(nr_to_scan, |
| 1320 | &page_list, &nr_scanned, sc->order, |
| 1321 | sc->lumpy_reclaim_mode ? |
| 1322 | ISOLATE_BOTH : ISOLATE_INACTIVE, |
| 1323 | zone, sc->mem_cgroup, |
| 1324 | 0, file); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1325 | /* |
KOSAKI Motohiro | e247dbc | 2010-08-09 17:19:28 -0700 | [diff] [blame] | 1326 | * mem_cgroup_isolate_pages() keeps track of |
| 1327 | * scanned pages on its own. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1328 | */ |
KOSAKI Motohiro | e247dbc | 2010-08-09 17:19:28 -0700 | [diff] [blame] | 1329 | } |
KOSAKI Motohiro | a731286 | 2009-09-21 17:01:37 -0700 | [diff] [blame] | 1330 | |
Mel Gorman | 6663562 | 2010-08-09 17:19:30 -0700 | [diff] [blame] | 1331 | if (nr_taken == 0) { |
| 1332 | spin_unlock_irq(&zone->lru_lock); |
| 1333 | return 0; |
| 1334 | } |
KOSAKI Motohiro | e247dbc | 2010-08-09 17:19:28 -0700 | [diff] [blame] | 1335 | |
Mel Gorman | 1489fa1 | 2010-08-09 17:19:33 -0700 | [diff] [blame] | 1336 | update_isolated_counts(zone, sc, &nr_anon, &nr_file, &page_list); |
KOSAKI Motohiro | e247dbc | 2010-08-09 17:19:28 -0700 | [diff] [blame] | 1337 | |
| 1338 | spin_unlock_irq(&zone->lru_lock); |
| 1339 | |
| 1340 | nr_reclaimed = shrink_page_list(&page_list, sc, PAGEOUT_IO_ASYNC); |
| 1341 | |
Wu Fengguang | e31f3698 | 2010-08-09 17:20:01 -0700 | [diff] [blame] | 1342 | /* Check if we should syncronously wait for writeback */ |
| 1343 | if (should_reclaim_stall(nr_taken, nr_reclaimed, priority, sc)) { |
KOSAKI Motohiro | e247dbc | 2010-08-09 17:19:28 -0700 | [diff] [blame] | 1344 | congestion_wait(BLK_RW_ASYNC, HZ/10); |
| 1345 | |
| 1346 | /* |
| 1347 | * The attempt at page out may have made some |
| 1348 | * of the pages active, mark them inactive again. |
| 1349 | */ |
Mel Gorman | 1489fa1 | 2010-08-09 17:19:33 -0700 | [diff] [blame] | 1350 | nr_active = clear_active_flags(&page_list, NULL); |
KOSAKI Motohiro | e247dbc | 2010-08-09 17:19:28 -0700 | [diff] [blame] | 1351 | count_vm_events(PGDEACTIVATE, nr_active); |
| 1352 | |
| 1353 | nr_reclaimed += shrink_page_list(&page_list, sc, PAGEOUT_IO_SYNC); |
| 1354 | } |
| 1355 | |
| 1356 | local_irq_disable(); |
| 1357 | if (current_is_kswapd()) |
| 1358 | __count_vm_events(KSWAPD_STEAL, nr_reclaimed); |
| 1359 | __count_zone_vm_events(PGSTEAL, zone, nr_reclaimed); |
| 1360 | |
Mel Gorman | 1489fa1 | 2010-08-09 17:19:33 -0700 | [diff] [blame] | 1361 | putback_lru_pages(zone, sc, nr_anon, nr_file, &page_list); |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1362 | return nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1363 | } |
| 1364 | |
Martin Bligh | 3bb1a852 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1365 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1366 | * This moves pages from the active list to the inactive list. |
| 1367 | * |
| 1368 | * We move them the other way if the page is referenced by one or more |
| 1369 | * processes, from rmap. |
| 1370 | * |
| 1371 | * If the pages are mostly unmapped, the processing is fast and it is |
| 1372 | * appropriate to hold zone->lru_lock across the whole operation. But if |
| 1373 | * the pages are mapped, the processing is slow (page_referenced()) so we |
| 1374 | * should drop zone->lru_lock around each page. It's impossible to balance |
| 1375 | * this, so instead we remove the pages from the LRU while processing them. |
| 1376 | * It is safe to rely on PG_active against the non-LRU pages in here because |
| 1377 | * nobody will play with that bit on a non-LRU page. |
| 1378 | * |
| 1379 | * The downside is that we have to touch page->_count against each page. |
| 1380 | * But we had to alter page->flags anyway. |
| 1381 | */ |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1382 | |
Wu Fengguang | 3eb4140 | 2009-06-16 15:33:13 -0700 | [diff] [blame] | 1383 | static void move_active_pages_to_lru(struct zone *zone, |
| 1384 | struct list_head *list, |
| 1385 | enum lru_list lru) |
| 1386 | { |
| 1387 | unsigned long pgmoved = 0; |
| 1388 | struct pagevec pvec; |
| 1389 | struct page *page; |
| 1390 | |
| 1391 | pagevec_init(&pvec, 1); |
| 1392 | |
| 1393 | while (!list_empty(list)) { |
| 1394 | page = lru_to_page(list); |
Wu Fengguang | 3eb4140 | 2009-06-16 15:33:13 -0700 | [diff] [blame] | 1395 | |
| 1396 | VM_BUG_ON(PageLRU(page)); |
| 1397 | SetPageLRU(page); |
| 1398 | |
Wu Fengguang | 3eb4140 | 2009-06-16 15:33:13 -0700 | [diff] [blame] | 1399 | list_move(&page->lru, &zone->lru[lru].list); |
| 1400 | mem_cgroup_add_lru_list(page, lru); |
| 1401 | pgmoved++; |
| 1402 | |
| 1403 | if (!pagevec_add(&pvec, page) || list_empty(list)) { |
| 1404 | spin_unlock_irq(&zone->lru_lock); |
| 1405 | if (buffer_heads_over_limit) |
| 1406 | pagevec_strip(&pvec); |
| 1407 | __pagevec_release(&pvec); |
| 1408 | spin_lock_irq(&zone->lru_lock); |
| 1409 | } |
| 1410 | } |
| 1411 | __mod_zone_page_state(zone, NR_LRU_BASE + lru, pgmoved); |
| 1412 | if (!is_active_lru(lru)) |
| 1413 | __count_vm_events(PGDEACTIVATE, pgmoved); |
| 1414 | } |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1415 | |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 1416 | static void shrink_active_list(unsigned long nr_pages, struct zone *zone, |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1417 | struct scan_control *sc, int priority, int file) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1418 | { |
KOSAKI Motohiro | 44c241f | 2009-09-21 17:01:35 -0700 | [diff] [blame] | 1419 | unsigned long nr_taken; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1420 | unsigned long pgscanned; |
Wu Fengguang | 6fe6b7e | 2009-06-16 15:33:05 -0700 | [diff] [blame] | 1421 | unsigned long vm_flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1422 | LIST_HEAD(l_hold); /* The pages which were snipped off */ |
Wu Fengguang | 8cab475 | 2009-06-16 15:33:12 -0700 | [diff] [blame] | 1423 | LIST_HEAD(l_active); |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1424 | LIST_HEAD(l_inactive); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1425 | struct page *page; |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1426 | struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc); |
KOSAKI Motohiro | 44c241f | 2009-09-21 17:01:35 -0700 | [diff] [blame] | 1427 | unsigned long nr_rotated = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1428 | |
| 1429 | lru_add_drain(); |
| 1430 | spin_lock_irq(&zone->lru_lock); |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1431 | if (scanning_global_lru(sc)) { |
Johannes Weiner | 8b25c6d | 2010-05-24 14:32:40 -0700 | [diff] [blame] | 1432 | nr_taken = isolate_pages_global(nr_pages, &l_hold, |
| 1433 | &pgscanned, sc->order, |
| 1434 | ISOLATE_ACTIVE, zone, |
| 1435 | 1, file); |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1436 | zone->pages_scanned += pgscanned; |
Johannes Weiner | 8b25c6d | 2010-05-24 14:32:40 -0700 | [diff] [blame] | 1437 | } else { |
| 1438 | nr_taken = mem_cgroup_isolate_pages(nr_pages, &l_hold, |
| 1439 | &pgscanned, sc->order, |
| 1440 | ISOLATE_ACTIVE, zone, |
| 1441 | sc->mem_cgroup, 1, file); |
| 1442 | /* |
| 1443 | * mem_cgroup_isolate_pages() keeps track of |
| 1444 | * scanned pages on its own. |
| 1445 | */ |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1446 | } |
Johannes Weiner | 8b25c6d | 2010-05-24 14:32:40 -0700 | [diff] [blame] | 1447 | |
Johannes Weiner | b7c46d1 | 2009-09-21 17:02:56 -0700 | [diff] [blame] | 1448 | reclaim_stat->recent_scanned[file] += nr_taken; |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1449 | |
Wu Fengguang | 3eb4140 | 2009-06-16 15:33:13 -0700 | [diff] [blame] | 1450 | __count_zone_vm_events(PGREFILL, zone, pgscanned); |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1451 | if (file) |
KOSAKI Motohiro | 44c241f | 2009-09-21 17:01:35 -0700 | [diff] [blame] | 1452 | __mod_zone_page_state(zone, NR_ACTIVE_FILE, -nr_taken); |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1453 | else |
KOSAKI Motohiro | 44c241f | 2009-09-21 17:01:35 -0700 | [diff] [blame] | 1454 | __mod_zone_page_state(zone, NR_ACTIVE_ANON, -nr_taken); |
KOSAKI Motohiro | a731286 | 2009-09-21 17:01:37 -0700 | [diff] [blame] | 1455 | __mod_zone_page_state(zone, NR_ISOLATED_ANON + file, nr_taken); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1456 | spin_unlock_irq(&zone->lru_lock); |
| 1457 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1458 | while (!list_empty(&l_hold)) { |
| 1459 | cond_resched(); |
| 1460 | page = lru_to_page(&l_hold); |
| 1461 | list_del(&page->lru); |
Rik van Riel | 7e9cd48 | 2008-10-18 20:26:35 -0700 | [diff] [blame] | 1462 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 1463 | if (unlikely(!page_evictable(page, NULL))) { |
| 1464 | putback_lru_page(page); |
| 1465 | continue; |
| 1466 | } |
| 1467 | |
Johannes Weiner | 64574746 | 2010-03-05 13:42:22 -0800 | [diff] [blame] | 1468 | if (page_referenced(page, 0, sc->mem_cgroup, &vm_flags)) { |
KOSAKI Motohiro | 44c241f | 2009-09-21 17:01:35 -0700 | [diff] [blame] | 1469 | nr_rotated++; |
Wu Fengguang | 8cab475 | 2009-06-16 15:33:12 -0700 | [diff] [blame] | 1470 | /* |
| 1471 | * Identify referenced, file-backed active pages and |
| 1472 | * give them one more trip around the active list. So |
| 1473 | * that executable code get better chances to stay in |
| 1474 | * memory under moderate memory pressure. Anon pages |
| 1475 | * are not likely to be evicted by use-once streaming |
| 1476 | * IO, plus JVM can create lots of anon VM_EXEC pages, |
| 1477 | * so we ignore them here. |
| 1478 | */ |
Wu Fengguang | 41e2098 | 2009-10-26 16:49:53 -0700 | [diff] [blame] | 1479 | if ((vm_flags & VM_EXEC) && page_is_file_cache(page)) { |
Wu Fengguang | 8cab475 | 2009-06-16 15:33:12 -0700 | [diff] [blame] | 1480 | list_add(&page->lru, &l_active); |
| 1481 | continue; |
| 1482 | } |
| 1483 | } |
Rik van Riel | 7e9cd48 | 2008-10-18 20:26:35 -0700 | [diff] [blame] | 1484 | |
KOSAKI Motohiro | 5205e56 | 2009-09-21 17:01:44 -0700 | [diff] [blame] | 1485 | ClearPageActive(page); /* we are de-activating */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1486 | list_add(&page->lru, &l_inactive); |
| 1487 | } |
| 1488 | |
Andrew Morton | b555749 | 2009-01-06 14:40:13 -0800 | [diff] [blame] | 1489 | /* |
Wu Fengguang | 8cab475 | 2009-06-16 15:33:12 -0700 | [diff] [blame] | 1490 | * Move pages back to the lru list. |
Andrew Morton | b555749 | 2009-01-06 14:40:13 -0800 | [diff] [blame] | 1491 | */ |
Johannes Weiner | 2a1dc50 | 2008-12-01 03:00:35 +0100 | [diff] [blame] | 1492 | spin_lock_irq(&zone->lru_lock); |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1493 | /* |
Wu Fengguang | 8cab475 | 2009-06-16 15:33:12 -0700 | [diff] [blame] | 1494 | * Count referenced pages from currently used mappings as rotated, |
| 1495 | * even though only some of them are actually re-activated. This |
| 1496 | * helps balance scan pressure between file and anonymous pages in |
| 1497 | * get_scan_ratio. |
Rik van Riel | 7e9cd48 | 2008-10-18 20:26:35 -0700 | [diff] [blame] | 1498 | */ |
Johannes Weiner | b7c46d1 | 2009-09-21 17:02:56 -0700 | [diff] [blame] | 1499 | reclaim_stat->recent_rotated[file] += nr_rotated; |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 1500 | |
Wu Fengguang | 3eb4140 | 2009-06-16 15:33:13 -0700 | [diff] [blame] | 1501 | move_active_pages_to_lru(zone, &l_active, |
| 1502 | LRU_ACTIVE + file * LRU_FILE); |
| 1503 | move_active_pages_to_lru(zone, &l_inactive, |
| 1504 | LRU_BASE + file * LRU_FILE); |
KOSAKI Motohiro | a731286 | 2009-09-21 17:01:37 -0700 | [diff] [blame] | 1505 | __mod_zone_page_state(zone, NR_ISOLATED_ANON + file, -nr_taken); |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 1506 | spin_unlock_irq(&zone->lru_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1507 | } |
| 1508 | |
KOSAKI Motohiro | 14797e2 | 2009-01-07 18:08:18 -0800 | [diff] [blame] | 1509 | static int inactive_anon_is_low_global(struct zone *zone) |
KOSAKI Motohiro | f89eb90 | 2009-01-07 18:08:14 -0800 | [diff] [blame] | 1510 | { |
| 1511 | unsigned long active, inactive; |
| 1512 | |
| 1513 | active = zone_page_state(zone, NR_ACTIVE_ANON); |
| 1514 | inactive = zone_page_state(zone, NR_INACTIVE_ANON); |
| 1515 | |
| 1516 | if (inactive * zone->inactive_ratio < active) |
| 1517 | return 1; |
| 1518 | |
| 1519 | return 0; |
| 1520 | } |
| 1521 | |
KOSAKI Motohiro | 14797e2 | 2009-01-07 18:08:18 -0800 | [diff] [blame] | 1522 | /** |
| 1523 | * inactive_anon_is_low - check if anonymous pages need to be deactivated |
| 1524 | * @zone: zone to check |
| 1525 | * @sc: scan control of this context |
| 1526 | * |
| 1527 | * Returns true if the zone does not have enough inactive anon pages, |
| 1528 | * meaning some active anon pages need to be deactivated. |
| 1529 | */ |
| 1530 | static int inactive_anon_is_low(struct zone *zone, struct scan_control *sc) |
| 1531 | { |
| 1532 | int low; |
| 1533 | |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1534 | if (scanning_global_lru(sc)) |
KOSAKI Motohiro | 14797e2 | 2009-01-07 18:08:18 -0800 | [diff] [blame] | 1535 | low = inactive_anon_is_low_global(zone); |
| 1536 | else |
KOSAKI Motohiro | c772be9 | 2009-01-07 18:08:25 -0800 | [diff] [blame] | 1537 | low = mem_cgroup_inactive_anon_is_low(sc->mem_cgroup); |
KOSAKI Motohiro | 14797e2 | 2009-01-07 18:08:18 -0800 | [diff] [blame] | 1538 | return low; |
| 1539 | } |
| 1540 | |
Rik van Riel | 56e49d2 | 2009-06-16 15:32:28 -0700 | [diff] [blame] | 1541 | static int inactive_file_is_low_global(struct zone *zone) |
| 1542 | { |
| 1543 | unsigned long active, inactive; |
| 1544 | |
| 1545 | active = zone_page_state(zone, NR_ACTIVE_FILE); |
| 1546 | inactive = zone_page_state(zone, NR_INACTIVE_FILE); |
| 1547 | |
| 1548 | return (active > inactive); |
| 1549 | } |
| 1550 | |
| 1551 | /** |
| 1552 | * inactive_file_is_low - check if file pages need to be deactivated |
| 1553 | * @zone: zone to check |
| 1554 | * @sc: scan control of this context |
| 1555 | * |
| 1556 | * When the system is doing streaming IO, memory pressure here |
| 1557 | * ensures that active file pages get deactivated, until more |
| 1558 | * than half of the file pages are on the inactive list. |
| 1559 | * |
| 1560 | * Once we get to that situation, protect the system's working |
| 1561 | * set from being evicted by disabling active file page aging. |
| 1562 | * |
| 1563 | * This uses a different ratio than the anonymous pages, because |
| 1564 | * the page cache uses a use-once replacement algorithm. |
| 1565 | */ |
| 1566 | static int inactive_file_is_low(struct zone *zone, struct scan_control *sc) |
| 1567 | { |
| 1568 | int low; |
| 1569 | |
| 1570 | if (scanning_global_lru(sc)) |
| 1571 | low = inactive_file_is_low_global(zone); |
| 1572 | else |
| 1573 | low = mem_cgroup_inactive_file_is_low(sc->mem_cgroup); |
| 1574 | return low; |
| 1575 | } |
| 1576 | |
Rik van Riel | b39415b | 2009-12-14 17:59:48 -0800 | [diff] [blame] | 1577 | static int inactive_list_is_low(struct zone *zone, struct scan_control *sc, |
| 1578 | int file) |
| 1579 | { |
| 1580 | if (file) |
| 1581 | return inactive_file_is_low(zone, sc); |
| 1582 | else |
| 1583 | return inactive_anon_is_low(zone, sc); |
| 1584 | } |
| 1585 | |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1586 | static unsigned long shrink_list(enum lru_list lru, unsigned long nr_to_scan, |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1587 | struct zone *zone, struct scan_control *sc, int priority) |
| 1588 | { |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1589 | int file = is_file_lru(lru); |
| 1590 | |
Rik van Riel | b39415b | 2009-12-14 17:59:48 -0800 | [diff] [blame] | 1591 | if (is_active_lru(lru)) { |
| 1592 | if (inactive_list_is_low(zone, sc, file)) |
| 1593 | shrink_active_list(nr_to_scan, zone, sc, priority, file); |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 1594 | return 0; |
| 1595 | } |
| 1596 | |
Rik van Riel | 33c120e | 2008-10-18 20:26:36 -0700 | [diff] [blame] | 1597 | return shrink_inactive_list(nr_to_scan, zone, sc, priority, file); |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1598 | } |
| 1599 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1600 | /* |
Shaohua Li | 76a33fc | 2010-05-24 14:32:36 -0700 | [diff] [blame] | 1601 | * Smallish @nr_to_scan's are deposited in @nr_saved_scan, |
| 1602 | * until we collected @swap_cluster_max pages to scan. |
| 1603 | */ |
| 1604 | static unsigned long nr_scan_try_batch(unsigned long nr_to_scan, |
| 1605 | unsigned long *nr_saved_scan) |
| 1606 | { |
| 1607 | unsigned long nr; |
| 1608 | |
| 1609 | *nr_saved_scan += nr_to_scan; |
| 1610 | nr = *nr_saved_scan; |
| 1611 | |
| 1612 | if (nr >= SWAP_CLUSTER_MAX) |
| 1613 | *nr_saved_scan = 0; |
| 1614 | else |
| 1615 | nr = 0; |
| 1616 | |
| 1617 | return nr; |
| 1618 | } |
| 1619 | |
| 1620 | /* |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1621 | * Determine how aggressively the anon and file LRU lists should be |
| 1622 | * scanned. The relative value of each set of LRU lists is determined |
| 1623 | * by looking at the fraction of the pages scanned we did rotate back |
| 1624 | * onto the active list instead of evict. |
| 1625 | * |
Shaohua Li | 76a33fc | 2010-05-24 14:32:36 -0700 | [diff] [blame] | 1626 | * nr[0] = anon pages to scan; nr[1] = file pages to scan |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1627 | */ |
Shaohua Li | 76a33fc | 2010-05-24 14:32:36 -0700 | [diff] [blame] | 1628 | static void get_scan_count(struct zone *zone, struct scan_control *sc, |
| 1629 | unsigned long *nr, int priority) |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1630 | { |
| 1631 | unsigned long anon, file, free; |
| 1632 | unsigned long anon_prio, file_prio; |
| 1633 | unsigned long ap, fp; |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1634 | struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc); |
Shaohua Li | 76a33fc | 2010-05-24 14:32:36 -0700 | [diff] [blame] | 1635 | u64 fraction[2], denominator; |
| 1636 | enum lru_list l; |
| 1637 | int noswap = 0; |
| 1638 | |
| 1639 | /* If we have no swap space, do not bother scanning anon pages. */ |
| 1640 | if (!sc->may_swap || (nr_swap_pages <= 0)) { |
| 1641 | noswap = 1; |
| 1642 | fraction[0] = 0; |
| 1643 | fraction[1] = 1; |
| 1644 | denominator = 1; |
| 1645 | goto out; |
| 1646 | } |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1647 | |
Vincent Li | 0b21767 | 2009-09-21 17:03:09 -0700 | [diff] [blame] | 1648 | anon = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_ANON) + |
| 1649 | zone_nr_lru_pages(zone, sc, LRU_INACTIVE_ANON); |
| 1650 | file = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_FILE) + |
| 1651 | zone_nr_lru_pages(zone, sc, LRU_INACTIVE_FILE); |
Hugh Dickins | b962716 | 2009-01-06 14:39:41 -0800 | [diff] [blame] | 1652 | |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1653 | if (scanning_global_lru(sc)) { |
KOSAKI Motohiro | eeee9a8 | 2009-01-07 18:08:17 -0800 | [diff] [blame] | 1654 | free = zone_page_state(zone, NR_FREE_PAGES); |
| 1655 | /* If we have very few page cache pages, |
| 1656 | force-scan anon pages. */ |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 1657 | if (unlikely(file + free <= high_wmark_pages(zone))) { |
Shaohua Li | 76a33fc | 2010-05-24 14:32:36 -0700 | [diff] [blame] | 1658 | fraction[0] = 1; |
| 1659 | fraction[1] = 0; |
| 1660 | denominator = 1; |
| 1661 | goto out; |
KOSAKI Motohiro | eeee9a8 | 2009-01-07 18:08:17 -0800 | [diff] [blame] | 1662 | } |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1663 | } |
| 1664 | |
| 1665 | /* |
KOSAKI Motohiro | 58c37f6 | 2010-08-09 17:19:51 -0700 | [diff] [blame] | 1666 | * With swappiness at 100, anonymous and file have the same priority. |
| 1667 | * This scanning priority is essentially the inverse of IO cost. |
| 1668 | */ |
| 1669 | anon_prio = sc->swappiness; |
| 1670 | file_prio = 200 - sc->swappiness; |
| 1671 | |
| 1672 | /* |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1673 | * OK, so we have swap space and a fair amount of page cache |
| 1674 | * pages. We use the recently rotated / recently scanned |
| 1675 | * ratios to determine how valuable each cache is. |
| 1676 | * |
| 1677 | * Because workloads change over time (and to avoid overflow) |
| 1678 | * we keep these statistics as a floating average, which ends |
| 1679 | * up weighing recent references more than old ones. |
| 1680 | * |
| 1681 | * anon in [0], file in [1] |
| 1682 | */ |
KOSAKI Motohiro | 58c37f6 | 2010-08-09 17:19:51 -0700 | [diff] [blame] | 1683 | spin_lock_irq(&zone->lru_lock); |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1684 | if (unlikely(reclaim_stat->recent_scanned[0] > anon / 4)) { |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1685 | reclaim_stat->recent_scanned[0] /= 2; |
| 1686 | reclaim_stat->recent_rotated[0] /= 2; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1687 | } |
| 1688 | |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1689 | if (unlikely(reclaim_stat->recent_scanned[1] > file / 4)) { |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1690 | reclaim_stat->recent_scanned[1] /= 2; |
| 1691 | reclaim_stat->recent_rotated[1] /= 2; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1692 | } |
| 1693 | |
| 1694 | /* |
Rik van Riel | 00d8089 | 2008-11-19 15:36:44 -0800 | [diff] [blame] | 1695 | * The amount of pressure on anon vs file pages is inversely |
| 1696 | * proportional to the fraction of recently scanned pages on |
| 1697 | * each list that were recently referenced and in active use. |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1698 | */ |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1699 | ap = (anon_prio + 1) * (reclaim_stat->recent_scanned[0] + 1); |
| 1700 | ap /= reclaim_stat->recent_rotated[0] + 1; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1701 | |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1702 | fp = (file_prio + 1) * (reclaim_stat->recent_scanned[1] + 1); |
| 1703 | fp /= reclaim_stat->recent_rotated[1] + 1; |
KOSAKI Motohiro | 58c37f6 | 2010-08-09 17:19:51 -0700 | [diff] [blame] | 1704 | spin_unlock_irq(&zone->lru_lock); |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1705 | |
Shaohua Li | 76a33fc | 2010-05-24 14:32:36 -0700 | [diff] [blame] | 1706 | fraction[0] = ap; |
| 1707 | fraction[1] = fp; |
| 1708 | denominator = ap + fp + 1; |
| 1709 | out: |
| 1710 | for_each_evictable_lru(l) { |
| 1711 | int file = is_file_lru(l); |
| 1712 | unsigned long scan; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1713 | |
Shaohua Li | 76a33fc | 2010-05-24 14:32:36 -0700 | [diff] [blame] | 1714 | scan = zone_nr_lru_pages(zone, sc, l); |
| 1715 | if (priority || noswap) { |
| 1716 | scan >>= priority; |
| 1717 | scan = div64_u64(scan * fraction[file], denominator); |
| 1718 | } |
| 1719 | nr[l] = nr_scan_try_batch(scan, |
| 1720 | &reclaim_stat->nr_saved_scan[l]); |
| 1721 | } |
Wu Fengguang | 6e08a36 | 2009-06-16 15:32:29 -0700 | [diff] [blame] | 1722 | } |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1723 | |
KOSAKI Motohiro | 5f53e76 | 2010-05-24 14:32:37 -0700 | [diff] [blame] | 1724 | static void set_lumpy_reclaim_mode(int priority, struct scan_control *sc) |
| 1725 | { |
| 1726 | /* |
| 1727 | * If we need a large contiguous chunk of memory, or have |
| 1728 | * trouble getting a small set of contiguous pages, we |
| 1729 | * will reclaim both active and inactive pages. |
| 1730 | */ |
| 1731 | if (sc->order > PAGE_ALLOC_COSTLY_ORDER) |
| 1732 | sc->lumpy_reclaim_mode = 1; |
| 1733 | else if (sc->order && priority < DEF_PRIORITY - 2) |
| 1734 | sc->lumpy_reclaim_mode = 1; |
| 1735 | else |
| 1736 | sc->lumpy_reclaim_mode = 0; |
| 1737 | } |
| 1738 | |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1739 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1740 | * This is a basic per-zone page freer. Used by both kswapd and direct reclaim. |
| 1741 | */ |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1742 | static void shrink_zone(int priority, struct zone *zone, |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1743 | struct scan_control *sc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1744 | { |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1745 | unsigned long nr[NR_LRU_LISTS]; |
Christoph Lameter | 8695949 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 1746 | unsigned long nr_to_scan; |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1747 | enum lru_list l; |
KOSAKI Motohiro | 01dbe5c | 2009-01-06 14:40:02 -0800 | [diff] [blame] | 1748 | unsigned long nr_reclaimed = sc->nr_reclaimed; |
KOSAKI Motohiro | 22fba33 | 2009-12-14 17:59:10 -0800 | [diff] [blame] | 1749 | unsigned long nr_to_reclaim = sc->nr_to_reclaim; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1750 | |
Shaohua Li | 76a33fc | 2010-05-24 14:32:36 -0700 | [diff] [blame] | 1751 | get_scan_count(zone, sc, nr, priority); |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1752 | |
KOSAKI Motohiro | 5f53e76 | 2010-05-24 14:32:37 -0700 | [diff] [blame] | 1753 | set_lumpy_reclaim_mode(priority, sc); |
| 1754 | |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 1755 | while (nr[LRU_INACTIVE_ANON] || nr[LRU_ACTIVE_FILE] || |
| 1756 | nr[LRU_INACTIVE_FILE]) { |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 1757 | for_each_evictable_lru(l) { |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1758 | if (nr[l]) { |
KOSAKI Motohiro | ece74b2 | 2009-12-14 17:59:14 -0800 | [diff] [blame] | 1759 | nr_to_scan = min_t(unsigned long, |
| 1760 | nr[l], SWAP_CLUSTER_MAX); |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1761 | nr[l] -= nr_to_scan; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1762 | |
KOSAKI Motohiro | 01dbe5c | 2009-01-06 14:40:02 -0800 | [diff] [blame] | 1763 | nr_reclaimed += shrink_list(l, nr_to_scan, |
| 1764 | zone, sc, priority); |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1765 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1766 | } |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1767 | /* |
| 1768 | * On large memory systems, scan >> priority can become |
| 1769 | * really large. This is fine for the starting priority; |
| 1770 | * we want to put equal scanning pressure on each zone. |
| 1771 | * However, if the VM has a harder time of freeing pages, |
| 1772 | * with multiple processes reclaiming pages, the total |
| 1773 | * freeing target can get unreasonably large. |
| 1774 | */ |
KOSAKI Motohiro | 338fde9 | 2009-12-14 17:59:15 -0800 | [diff] [blame] | 1775 | if (nr_reclaimed >= nr_to_reclaim && priority < DEF_PRIORITY) |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1776 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1777 | } |
| 1778 | |
KOSAKI Motohiro | 01dbe5c | 2009-01-06 14:40:02 -0800 | [diff] [blame] | 1779 | sc->nr_reclaimed = nr_reclaimed; |
| 1780 | |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 1781 | /* |
| 1782 | * Even if we did not try to evict anon pages at all, we want to |
| 1783 | * rebalance the anon lru active/inactive ratio. |
| 1784 | */ |
MinChan Kim | 69c8548 | 2009-06-16 15:32:44 -0700 | [diff] [blame] | 1785 | if (inactive_anon_is_low(zone, sc) && nr_swap_pages > 0) |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 1786 | shrink_active_list(SWAP_CLUSTER_MAX, zone, sc, priority, 0); |
| 1787 | |
Andrew Morton | 232ea4d | 2007-02-28 20:13:21 -0800 | [diff] [blame] | 1788 | throttle_vm_writeout(sc->gfp_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1789 | } |
| 1790 | |
| 1791 | /* |
| 1792 | * This is the direct reclaim path, for page-allocating processes. We only |
| 1793 | * try to reclaim pages from zones which will satisfy the caller's allocation |
| 1794 | * request. |
| 1795 | * |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 1796 | * We reclaim from a zone even if that zone is over high_wmark_pages(zone). |
| 1797 | * Because: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1798 | * a) The caller may be trying to free *extra* pages to satisfy a higher-order |
| 1799 | * allocation or |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 1800 | * b) The target zone may be at high_wmark_pages(zone) but the lower zones |
| 1801 | * must go *over* high_wmark_pages(zone) to satisfy the `incremental min' |
| 1802 | * zone defense algorithm. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1803 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1804 | * If a zone is deemed to be full of pinned pages then just give it a light |
| 1805 | * scan then give up on it. |
| 1806 | */ |
KOSAKI Motohiro | bb21c7c | 2010-06-04 14:15:05 -0700 | [diff] [blame] | 1807 | static bool shrink_zones(int priority, struct zonelist *zonelist, |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1808 | struct scan_control *sc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1809 | { |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1810 | struct zoneref *z; |
Mel Gorman | 54a6eb5 | 2008-04-28 02:12:16 -0700 | [diff] [blame] | 1811 | struct zone *zone; |
KOSAKI Motohiro | bb21c7c | 2010-06-04 14:15:05 -0700 | [diff] [blame] | 1812 | bool all_unreclaimable = true; |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1813 | |
Mel Gorman | d4debc6 | 2010-08-09 17:19:29 -0700 | [diff] [blame] | 1814 | for_each_zone_zonelist_nodemask(zone, z, zonelist, |
| 1815 | gfp_zone(sc->gfp_mask), sc->nodemask) { |
Con Kolivas | f3fe651 | 2006-01-06 00:11:15 -0800 | [diff] [blame] | 1816 | if (!populated_zone(zone)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1817 | continue; |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1818 | /* |
| 1819 | * Take care memory controller reclaiming has small influence |
| 1820 | * to global LRU. |
| 1821 | */ |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1822 | if (scanning_global_lru(sc)) { |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1823 | if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) |
| 1824 | continue; |
KOSAKI Motohiro | 93e4a89 | 2010-03-05 13:41:55 -0800 | [diff] [blame] | 1825 | if (zone->all_unreclaimable && priority != DEF_PRIORITY) |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1826 | continue; /* Let kswapd poll it */ |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1827 | } |
Nick Piggin | 408d854 | 2006-09-25 23:31:27 -0700 | [diff] [blame] | 1828 | |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1829 | shrink_zone(priority, zone, sc); |
KOSAKI Motohiro | bb21c7c | 2010-06-04 14:15:05 -0700 | [diff] [blame] | 1830 | all_unreclaimable = false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1831 | } |
KOSAKI Motohiro | bb21c7c | 2010-06-04 14:15:05 -0700 | [diff] [blame] | 1832 | return all_unreclaimable; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1833 | } |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1834 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1835 | /* |
| 1836 | * This is the main entry point to direct page reclaim. |
| 1837 | * |
| 1838 | * If a full scan of the inactive list fails to free enough memory then we |
| 1839 | * are "out of memory" and something needs to be killed. |
| 1840 | * |
| 1841 | * If the caller is !__GFP_FS then the probability of a failure is reasonably |
| 1842 | * 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] | 1843 | * caller can't do much about. We kick the writeback threads and take explicit |
| 1844 | * naps in the hope that some of these pages can be written. But if the |
| 1845 | * allocating task holds filesystem locks which prevent writeout this might not |
| 1846 | * work, and the allocation attempt will fail. |
Nishanth Aravamudan | a41f24e | 2008-04-29 00:58:25 -0700 | [diff] [blame] | 1847 | * |
| 1848 | * returns: 0, if no pages reclaimed |
| 1849 | * else, the number of pages reclaimed |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1850 | */ |
Mel Gorman | dac1d27 | 2008-04-28 02:12:12 -0700 | [diff] [blame] | 1851 | static unsigned long do_try_to_free_pages(struct zonelist *zonelist, |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1852 | struct scan_control *sc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1853 | { |
| 1854 | int priority; |
KOSAKI Motohiro | bb21c7c | 2010-06-04 14:15:05 -0700 | [diff] [blame] | 1855 | bool all_unreclaimable; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1856 | unsigned long total_scanned = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1857 | struct reclaim_state *reclaim_state = current->reclaim_state; |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1858 | struct zoneref *z; |
Mel Gorman | 54a6eb5 | 2008-04-28 02:12:16 -0700 | [diff] [blame] | 1859 | struct zone *zone; |
KOSAKI Motohiro | 22fba33 | 2009-12-14 17:59:10 -0800 | [diff] [blame] | 1860 | unsigned long writeback_threshold; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1861 | |
Miao Xie | c0ff745 | 2010-05-24 14:32:08 -0700 | [diff] [blame] | 1862 | get_mems_allowed(); |
Keika Kobayashi | 873b477 | 2008-07-25 01:48:52 -0700 | [diff] [blame] | 1863 | delayacct_freepages_start(); |
| 1864 | |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1865 | if (scanning_global_lru(sc)) |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1866 | count_vm_event(ALLOCSTALL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1867 | |
| 1868 | for (priority = DEF_PRIORITY; priority >= 0; priority--) { |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1869 | sc->nr_scanned = 0; |
Rik van Riel | f7b7fd8 | 2005-11-28 13:44:07 -0800 | [diff] [blame] | 1870 | if (!priority) |
| 1871 | disable_swap_token(); |
KOSAKI Motohiro | bb21c7c | 2010-06-04 14:15:05 -0700 | [diff] [blame] | 1872 | all_unreclaimable = shrink_zones(priority, zonelist, sc); |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1873 | /* |
| 1874 | * Don't shrink slabs when reclaiming memory from |
| 1875 | * over limit cgroups |
| 1876 | */ |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1877 | if (scanning_global_lru(sc)) { |
KOSAKI Motohiro | c6a8a8c | 2010-08-09 17:19:14 -0700 | [diff] [blame] | 1878 | unsigned long lru_pages = 0; |
Mel Gorman | d4debc6 | 2010-08-09 17:19:29 -0700 | [diff] [blame] | 1879 | for_each_zone_zonelist(zone, z, zonelist, |
| 1880 | gfp_zone(sc->gfp_mask)) { |
KOSAKI Motohiro | c6a8a8c | 2010-08-09 17:19:14 -0700 | [diff] [blame] | 1881 | if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) |
| 1882 | continue; |
| 1883 | |
| 1884 | lru_pages += zone_reclaimable_pages(zone); |
| 1885 | } |
| 1886 | |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1887 | shrink_slab(sc->nr_scanned, sc->gfp_mask, lru_pages); |
KAMEZAWA Hiroyuki | 91a4547 | 2008-02-07 00:14:29 -0800 | [diff] [blame] | 1888 | if (reclaim_state) { |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1889 | sc->nr_reclaimed += reclaim_state->reclaimed_slab; |
KAMEZAWA Hiroyuki | 91a4547 | 2008-02-07 00:14:29 -0800 | [diff] [blame] | 1890 | reclaim_state->reclaimed_slab = 0; |
| 1891 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1892 | } |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1893 | total_scanned += sc->nr_scanned; |
KOSAKI Motohiro | bb21c7c | 2010-06-04 14:15:05 -0700 | [diff] [blame] | 1894 | if (sc->nr_reclaimed >= sc->nr_to_reclaim) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1895 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1896 | |
| 1897 | /* |
| 1898 | * Try to write back as many pages as we just scanned. This |
| 1899 | * tends to cause slow streaming writers to write data to the |
| 1900 | * disk smoothly, at the dirtying rate, which is nice. But |
| 1901 | * that's undesirable in laptop mode, where we *want* lumpy |
| 1902 | * writeout. So in laptop mode, write out the whole world. |
| 1903 | */ |
KOSAKI Motohiro | 22fba33 | 2009-12-14 17:59:10 -0800 | [diff] [blame] | 1904 | writeback_threshold = sc->nr_to_reclaim + sc->nr_to_reclaim / 2; |
| 1905 | if (total_scanned > writeback_threshold) { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1906 | wakeup_flusher_threads(laptop_mode ? 0 : total_scanned); |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1907 | sc->may_writepage = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1908 | } |
| 1909 | |
| 1910 | /* Take a nap, wait for some writeback to complete */ |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame] | 1911 | if (!sc->hibernation_mode && sc->nr_scanned && |
| 1912 | priority < DEF_PRIORITY - 2) |
Jens Axboe | 8aa7e84 | 2009-07-09 14:52:32 +0200 | [diff] [blame] | 1913 | congestion_wait(BLK_RW_ASYNC, HZ/10); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1914 | } |
KOSAKI Motohiro | bb21c7c | 2010-06-04 14:15:05 -0700 | [diff] [blame] | 1915 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1916 | out: |
Martin Bligh | 3bb1a852 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1917 | /* |
| 1918 | * Now that we've scanned all the zones at this priority level, note |
| 1919 | * that level within the zone so that the next thread which performs |
| 1920 | * scanning of this zone will immediately start out at this priority |
| 1921 | * level. This affects only the decision whether or not to bring |
| 1922 | * mapped pages onto the inactive list. |
| 1923 | */ |
| 1924 | if (priority < 0) |
| 1925 | priority = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1926 | |
Keika Kobayashi | 873b477 | 2008-07-25 01:48:52 -0700 | [diff] [blame] | 1927 | delayacct_freepages_end(); |
Miao Xie | c0ff745 | 2010-05-24 14:32:08 -0700 | [diff] [blame] | 1928 | put_mems_allowed(); |
Keika Kobayashi | 873b477 | 2008-07-25 01:48:52 -0700 | [diff] [blame] | 1929 | |
KOSAKI Motohiro | bb21c7c | 2010-06-04 14:15:05 -0700 | [diff] [blame] | 1930 | if (sc->nr_reclaimed) |
| 1931 | return sc->nr_reclaimed; |
| 1932 | |
| 1933 | /* top priority shrink_zones still had more to do? don't OOM, then */ |
| 1934 | if (scanning_global_lru(sc) && !all_unreclaimable) |
| 1935 | return 1; |
| 1936 | |
| 1937 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1938 | } |
| 1939 | |
Mel Gorman | dac1d27 | 2008-04-28 02:12:12 -0700 | [diff] [blame] | 1940 | unsigned long try_to_free_pages(struct zonelist *zonelist, int order, |
KAMEZAWA Hiroyuki | 327c0e9 | 2009-03-31 15:23:31 -0700 | [diff] [blame] | 1941 | gfp_t gfp_mask, nodemask_t *nodemask) |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1942 | { |
Mel Gorman | 33906bc | 2010-08-09 17:19:16 -0700 | [diff] [blame] | 1943 | unsigned long nr_reclaimed; |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1944 | struct scan_control sc = { |
| 1945 | .gfp_mask = gfp_mask, |
| 1946 | .may_writepage = !laptop_mode, |
KOSAKI Motohiro | 22fba33 | 2009-12-14 17:59:10 -0800 | [diff] [blame] | 1947 | .nr_to_reclaim = SWAP_CLUSTER_MAX, |
Johannes Weiner | a6dc60f8 | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 1948 | .may_unmap = 1, |
KOSAKI Motohiro | 2e2e425 | 2009-04-21 12:24:57 -0700 | [diff] [blame] | 1949 | .may_swap = 1, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1950 | .swappiness = vm_swappiness, |
| 1951 | .order = order, |
| 1952 | .mem_cgroup = NULL, |
KAMEZAWA Hiroyuki | 327c0e9 | 2009-03-31 15:23:31 -0700 | [diff] [blame] | 1953 | .nodemask = nodemask, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1954 | }; |
| 1955 | |
Mel Gorman | 33906bc | 2010-08-09 17:19:16 -0700 | [diff] [blame] | 1956 | trace_mm_vmscan_direct_reclaim_begin(order, |
| 1957 | sc.may_writepage, |
| 1958 | gfp_mask); |
| 1959 | |
| 1960 | nr_reclaimed = do_try_to_free_pages(zonelist, &sc); |
| 1961 | |
| 1962 | trace_mm_vmscan_direct_reclaim_end(nr_reclaimed); |
| 1963 | |
| 1964 | return nr_reclaimed; |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1965 | } |
| 1966 | |
Balbir Singh | 00f0b82 | 2008-03-04 14:28:39 -0800 | [diff] [blame] | 1967 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1968 | |
Balbir Singh | 4e41695 | 2009-09-23 15:56:39 -0700 | [diff] [blame] | 1969 | unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem, |
| 1970 | gfp_t gfp_mask, bool noswap, |
| 1971 | unsigned int swappiness, |
| 1972 | struct zone *zone, int nid) |
| 1973 | { |
| 1974 | struct scan_control sc = { |
| 1975 | .may_writepage = !laptop_mode, |
| 1976 | .may_unmap = 1, |
| 1977 | .may_swap = !noswap, |
Balbir Singh | 4e41695 | 2009-09-23 15:56:39 -0700 | [diff] [blame] | 1978 | .swappiness = swappiness, |
| 1979 | .order = 0, |
| 1980 | .mem_cgroup = mem, |
Balbir Singh | 4e41695 | 2009-09-23 15:56:39 -0700 | [diff] [blame] | 1981 | }; |
| 1982 | nodemask_t nm = nodemask_of_node(nid); |
| 1983 | |
| 1984 | sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) | |
| 1985 | (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK); |
| 1986 | sc.nodemask = &nm; |
| 1987 | sc.nr_reclaimed = 0; |
| 1988 | sc.nr_scanned = 0; |
KOSAKI Motohiro | bdce6d9 | 2010-08-09 17:19:56 -0700 | [diff] [blame] | 1989 | |
| 1990 | trace_mm_vmscan_memcg_softlimit_reclaim_begin(0, |
| 1991 | sc.may_writepage, |
| 1992 | sc.gfp_mask); |
| 1993 | |
Balbir Singh | 4e41695 | 2009-09-23 15:56:39 -0700 | [diff] [blame] | 1994 | /* |
| 1995 | * NOTE: Although we can get the priority field, using it |
| 1996 | * here is not a good idea, since it limits the pages we can scan. |
| 1997 | * if we don't reclaim here, the shrink_zone from balance_pgdat |
| 1998 | * will pick up pages from other mem cgroup's as well. We hack |
| 1999 | * the priority and make it zero. |
| 2000 | */ |
| 2001 | shrink_zone(0, zone, &sc); |
KOSAKI Motohiro | bdce6d9 | 2010-08-09 17:19:56 -0700 | [diff] [blame] | 2002 | |
| 2003 | trace_mm_vmscan_memcg_softlimit_reclaim_end(sc.nr_reclaimed); |
| 2004 | |
Balbir Singh | 4e41695 | 2009-09-23 15:56:39 -0700 | [diff] [blame] | 2005 | return sc.nr_reclaimed; |
| 2006 | } |
| 2007 | |
Balbir Singh | e1a1cd5 | 2008-02-07 00:14:02 -0800 | [diff] [blame] | 2008 | unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont, |
KOSAKI Motohiro | a7885eb | 2009-01-07 18:08:24 -0800 | [diff] [blame] | 2009 | gfp_t gfp_mask, |
| 2010 | bool noswap, |
| 2011 | unsigned int swappiness) |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2012 | { |
Balbir Singh | 4e41695 | 2009-09-23 15:56:39 -0700 | [diff] [blame] | 2013 | struct zonelist *zonelist; |
KOSAKI Motohiro | bdce6d9 | 2010-08-09 17:19:56 -0700 | [diff] [blame] | 2014 | unsigned long nr_reclaimed; |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2015 | struct scan_control sc = { |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2016 | .may_writepage = !laptop_mode, |
Johannes Weiner | a6dc60f8 | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 2017 | .may_unmap = 1, |
KOSAKI Motohiro | 2e2e425 | 2009-04-21 12:24:57 -0700 | [diff] [blame] | 2018 | .may_swap = !noswap, |
KOSAKI Motohiro | 22fba33 | 2009-12-14 17:59:10 -0800 | [diff] [blame] | 2019 | .nr_to_reclaim = SWAP_CLUSTER_MAX, |
KOSAKI Motohiro | a7885eb | 2009-01-07 18:08:24 -0800 | [diff] [blame] | 2020 | .swappiness = swappiness, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2021 | .order = 0, |
| 2022 | .mem_cgroup = mem_cont, |
KAMEZAWA Hiroyuki | 327c0e9 | 2009-03-31 15:23:31 -0700 | [diff] [blame] | 2023 | .nodemask = NULL, /* we don't care the placement */ |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2024 | }; |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2025 | |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 2026 | sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) | |
| 2027 | (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK); |
| 2028 | zonelist = NODE_DATA(numa_node_id())->node_zonelists; |
KOSAKI Motohiro | bdce6d9 | 2010-08-09 17:19:56 -0700 | [diff] [blame] | 2029 | |
| 2030 | trace_mm_vmscan_memcg_reclaim_begin(0, |
| 2031 | sc.may_writepage, |
| 2032 | sc.gfp_mask); |
| 2033 | |
| 2034 | nr_reclaimed = do_try_to_free_pages(zonelist, &sc); |
| 2035 | |
| 2036 | trace_mm_vmscan_memcg_reclaim_end(nr_reclaimed); |
| 2037 | |
| 2038 | return nr_reclaimed; |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2039 | } |
| 2040 | #endif |
| 2041 | |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 2042 | /* is kswapd sleeping prematurely? */ |
KOSAKI Motohiro | bb3ab59 | 2009-12-14 17:58:55 -0800 | [diff] [blame] | 2043 | static int sleeping_prematurely(pg_data_t *pgdat, int order, long remaining) |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 2044 | { |
KOSAKI Motohiro | bb3ab59 | 2009-12-14 17:58:55 -0800 | [diff] [blame] | 2045 | int i; |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 2046 | |
| 2047 | /* If a direct reclaimer woke kswapd within HZ/10, it's premature */ |
| 2048 | if (remaining) |
| 2049 | return 1; |
| 2050 | |
| 2051 | /* If after HZ/10, a zone is below the high mark, it's premature */ |
KOSAKI Motohiro | bb3ab59 | 2009-12-14 17:58:55 -0800 | [diff] [blame] | 2052 | for (i = 0; i < pgdat->nr_zones; i++) { |
| 2053 | struct zone *zone = pgdat->node_zones + i; |
| 2054 | |
| 2055 | if (!populated_zone(zone)) |
| 2056 | continue; |
| 2057 | |
KOSAKI Motohiro | 93e4a89 | 2010-03-05 13:41:55 -0800 | [diff] [blame] | 2058 | if (zone->all_unreclaimable) |
KOSAKI Motohiro | de3fab3 | 2010-01-15 17:01:25 -0800 | [diff] [blame] | 2059 | continue; |
| 2060 | |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 2061 | if (!zone_watermark_ok(zone, order, high_wmark_pages(zone), |
| 2062 | 0, 0)) |
| 2063 | return 1; |
KOSAKI Motohiro | bb3ab59 | 2009-12-14 17:58:55 -0800 | [diff] [blame] | 2064 | } |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 2065 | |
| 2066 | return 0; |
| 2067 | } |
| 2068 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2069 | /* |
| 2070 | * 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] | 2071 | * they are all at high_wmark_pages(zone). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2072 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2073 | * Returns the number of pages which were actually freed. |
| 2074 | * |
| 2075 | * There is special handling here for zones which are full of pinned pages. |
| 2076 | * This can happen if the pages are all mlocked, or if they are all used by |
| 2077 | * device drivers (say, ZONE_DMA). Or if they are all in use by hugetlb. |
| 2078 | * What we do is to detect the case where all pages in the zone have been |
| 2079 | * scanned twice and there has been zero successful reclaim. Mark the zone as |
| 2080 | * dead and from now on, only perform a short scan. Basically we're polling |
| 2081 | * the zone for when the problem goes away. |
| 2082 | * |
| 2083 | * kswapd scans the zones in the highmem->normal->dma direction. It skips |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 2084 | * zones which have free_pages > high_wmark_pages(zone), but once a zone is |
| 2085 | * found to have free_pages <= high_wmark_pages(zone), we scan that zone and the |
| 2086 | * lower zones regardless of the number of free pages in the lower zones. This |
| 2087 | * interoperates with the page allocator fallback scheme to ensure that aging |
| 2088 | * of pages is balanced across the zones. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2089 | */ |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2090 | static unsigned long balance_pgdat(pg_data_t *pgdat, int order) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2091 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2092 | int all_zones_ok; |
| 2093 | int priority; |
| 2094 | int i; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 2095 | unsigned long total_scanned; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2096 | struct reclaim_state *reclaim_state = current->reclaim_state; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2097 | struct scan_control sc = { |
| 2098 | .gfp_mask = GFP_KERNEL, |
Johannes Weiner | a6dc60f8 | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 2099 | .may_unmap = 1, |
KOSAKI Motohiro | 2e2e425 | 2009-04-21 12:24:57 -0700 | [diff] [blame] | 2100 | .may_swap = 1, |
KOSAKI Motohiro | 22fba33 | 2009-12-14 17:59:10 -0800 | [diff] [blame] | 2101 | /* |
| 2102 | * kswapd doesn't want to be bailed out while reclaim. because |
| 2103 | * we want to put equal scanning pressure on each zone. |
| 2104 | */ |
| 2105 | .nr_to_reclaim = ULONG_MAX, |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2106 | .swappiness = vm_swappiness, |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 2107 | .order = order, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2108 | .mem_cgroup = NULL, |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2109 | }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2110 | loop_again: |
| 2111 | total_scanned = 0; |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 2112 | sc.nr_reclaimed = 0; |
Christoph Lameter | c0bbbc7 | 2006-06-11 15:22:26 -0700 | [diff] [blame] | 2113 | sc.may_writepage = !laptop_mode; |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 2114 | count_vm_event(PAGEOUTRUN); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2115 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2116 | for (priority = DEF_PRIORITY; priority >= 0; priority--) { |
| 2117 | int end_zone = 0; /* Inclusive. 0 = ZONE_DMA */ |
| 2118 | unsigned long lru_pages = 0; |
KOSAKI Motohiro | bb3ab59 | 2009-12-14 17:58:55 -0800 | [diff] [blame] | 2119 | int has_under_min_watermark_zone = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2120 | |
Rik van Riel | f7b7fd8 | 2005-11-28 13:44:07 -0800 | [diff] [blame] | 2121 | /* The swap token gets in the way of swapout... */ |
| 2122 | if (!priority) |
| 2123 | disable_swap_token(); |
| 2124 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2125 | all_zones_ok = 1; |
| 2126 | |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2127 | /* |
| 2128 | * Scan in the highmem->dma direction for the highest |
| 2129 | * zone which needs scanning |
| 2130 | */ |
| 2131 | for (i = pgdat->nr_zones - 1; i >= 0; i--) { |
| 2132 | struct zone *zone = pgdat->node_zones + i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2133 | |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2134 | if (!populated_zone(zone)) |
| 2135 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2136 | |
KOSAKI Motohiro | 93e4a89 | 2010-03-05 13:41:55 -0800 | [diff] [blame] | 2137 | if (zone->all_unreclaimable && priority != DEF_PRIORITY) |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2138 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2139 | |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 2140 | /* |
| 2141 | * Do some background aging of the anon list, to give |
| 2142 | * pages a chance to be referenced before reclaiming. |
| 2143 | */ |
KOSAKI Motohiro | 14797e2 | 2009-01-07 18:08:18 -0800 | [diff] [blame] | 2144 | if (inactive_anon_is_low(zone, &sc)) |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 2145 | shrink_active_list(SWAP_CLUSTER_MAX, zone, |
| 2146 | &sc, priority, 0); |
| 2147 | |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 2148 | if (!zone_watermark_ok(zone, order, |
| 2149 | high_wmark_pages(zone), 0, 0)) { |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2150 | end_zone = i; |
Andrew Morton | e1dbeda | 2006-12-06 20:32:01 -0800 | [diff] [blame] | 2151 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2152 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2153 | } |
Andrew Morton | e1dbeda | 2006-12-06 20:32:01 -0800 | [diff] [blame] | 2154 | if (i < 0) |
| 2155 | goto out; |
| 2156 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2157 | for (i = 0; i <= end_zone; i++) { |
| 2158 | struct zone *zone = pgdat->node_zones + i; |
| 2159 | |
Wu Fengguang | adea02a | 2009-09-21 17:01:42 -0700 | [diff] [blame] | 2160 | lru_pages += zone_reclaimable_pages(zone); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2161 | } |
| 2162 | |
| 2163 | /* |
| 2164 | * Now scan the zone in the dma->highmem direction, stopping |
| 2165 | * at the last zone which needs scanning. |
| 2166 | * |
| 2167 | * We do this because the page allocator works in the opposite |
| 2168 | * direction. This prevents the page allocator from allocating |
| 2169 | * pages behind kswapd's direction of progress, which would |
| 2170 | * cause too much scanning of the lower zones. |
| 2171 | */ |
| 2172 | for (i = 0; i <= end_zone; i++) { |
| 2173 | struct zone *zone = pgdat->node_zones + i; |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 2174 | int nr_slab; |
Balbir Singh | 4e41695 | 2009-09-23 15:56:39 -0700 | [diff] [blame] | 2175 | int nid, zid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2176 | |
Con Kolivas | f3fe651 | 2006-01-06 00:11:15 -0800 | [diff] [blame] | 2177 | if (!populated_zone(zone)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2178 | continue; |
| 2179 | |
KOSAKI Motohiro | 93e4a89 | 2010-03-05 13:41:55 -0800 | [diff] [blame] | 2180 | if (zone->all_unreclaimable && priority != DEF_PRIORITY) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2181 | continue; |
| 2182 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2183 | sc.nr_scanned = 0; |
Balbir Singh | 4e41695 | 2009-09-23 15:56:39 -0700 | [diff] [blame] | 2184 | |
| 2185 | nid = pgdat->node_id; |
| 2186 | zid = zone_idx(zone); |
| 2187 | /* |
| 2188 | * Call soft limit reclaim before calling shrink_zone. |
| 2189 | * For now we ignore the return value |
| 2190 | */ |
| 2191 | mem_cgroup_soft_limit_reclaim(zone, order, sc.gfp_mask, |
| 2192 | nid, zid); |
Rik van Riel | 32a4330 | 2007-10-16 01:24:50 -0700 | [diff] [blame] | 2193 | /* |
| 2194 | * We put equal pressure on every zone, unless one |
| 2195 | * zone has way too many pages free already. |
| 2196 | */ |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 2197 | if (!zone_watermark_ok(zone, order, |
| 2198 | 8*high_wmark_pages(zone), end_zone, 0)) |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 2199 | shrink_zone(priority, zone, &sc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2200 | reclaim_state->reclaimed_slab = 0; |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 2201 | nr_slab = shrink_slab(sc.nr_scanned, GFP_KERNEL, |
| 2202 | lru_pages); |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 2203 | sc.nr_reclaimed += reclaim_state->reclaimed_slab; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2204 | total_scanned += sc.nr_scanned; |
KOSAKI Motohiro | 93e4a89 | 2010-03-05 13:41:55 -0800 | [diff] [blame] | 2205 | if (zone->all_unreclaimable) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2206 | continue; |
KOSAKI Motohiro | 93e4a89 | 2010-03-05 13:41:55 -0800 | [diff] [blame] | 2207 | if (nr_slab == 0 && |
| 2208 | zone->pages_scanned >= (zone_reclaimable_pages(zone) * 6)) |
| 2209 | zone->all_unreclaimable = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2210 | /* |
| 2211 | * If we've done a decent amount of scanning and |
| 2212 | * the reclaim ratio is low, start doing writepage |
| 2213 | * even in laptop mode |
| 2214 | */ |
| 2215 | if (total_scanned > SWAP_CLUSTER_MAX * 2 && |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 2216 | total_scanned > sc.nr_reclaimed + sc.nr_reclaimed / 2) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2217 | sc.may_writepage = 1; |
KOSAKI Motohiro | bb3ab59 | 2009-12-14 17:58:55 -0800 | [diff] [blame] | 2218 | |
Minchan Kim | 45973d7 | 2010-03-05 13:41:45 -0800 | [diff] [blame] | 2219 | if (!zone_watermark_ok(zone, order, |
| 2220 | high_wmark_pages(zone), end_zone, 0)) { |
| 2221 | all_zones_ok = 0; |
| 2222 | /* |
| 2223 | * We are still under min water mark. This |
| 2224 | * means that we have a GFP_ATOMIC allocation |
| 2225 | * failure risk. Hurry up! |
| 2226 | */ |
| 2227 | if (!zone_watermark_ok(zone, order, |
| 2228 | min_wmark_pages(zone), end_zone, 0)) |
| 2229 | has_under_min_watermark_zone = 1; |
| 2230 | } |
KOSAKI Motohiro | bb3ab59 | 2009-12-14 17:58:55 -0800 | [diff] [blame] | 2231 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2232 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2233 | if (all_zones_ok) |
| 2234 | break; /* kswapd: all done */ |
| 2235 | /* |
| 2236 | * OK, kswapd is getting into trouble. Take a nap, then take |
| 2237 | * another pass across the zones. |
| 2238 | */ |
KOSAKI Motohiro | bb3ab59 | 2009-12-14 17:58:55 -0800 | [diff] [blame] | 2239 | if (total_scanned && (priority < DEF_PRIORITY - 2)) { |
| 2240 | if (has_under_min_watermark_zone) |
| 2241 | count_vm_event(KSWAPD_SKIP_CONGESTION_WAIT); |
| 2242 | else |
| 2243 | congestion_wait(BLK_RW_ASYNC, HZ/10); |
| 2244 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2245 | |
| 2246 | /* |
| 2247 | * We do this so kswapd doesn't build up large priorities for |
| 2248 | * example when it is freeing in parallel with allocators. It |
| 2249 | * matches the direct reclaim path behaviour in terms of impact |
| 2250 | * on zone->*_priority. |
| 2251 | */ |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 2252 | if (sc.nr_reclaimed >= SWAP_CLUSTER_MAX) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2253 | break; |
| 2254 | } |
| 2255 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2256 | if (!all_zones_ok) { |
| 2257 | cond_resched(); |
Rafael J. Wysocki | 8357376 | 2006-12-06 20:34:18 -0800 | [diff] [blame] | 2258 | |
| 2259 | try_to_freeze(); |
| 2260 | |
KOSAKI Motohiro | 73ce02e | 2009-01-06 14:40:33 -0800 | [diff] [blame] | 2261 | /* |
| 2262 | * Fragmentation may mean that the system cannot be |
| 2263 | * rebalanced for high-order allocations in all zones. |
| 2264 | * At this point, if nr_reclaimed < SWAP_CLUSTER_MAX, |
| 2265 | * it means the zones have been fully scanned and are still |
| 2266 | * not balanced. For high-order allocations, there is |
| 2267 | * little point trying all over again as kswapd may |
| 2268 | * infinite loop. |
| 2269 | * |
| 2270 | * Instead, recheck all watermarks at order-0 as they |
| 2271 | * are the most important. If watermarks are ok, kswapd will go |
| 2272 | * back to sleep. High-order users can still perform direct |
| 2273 | * reclaim if they wish. |
| 2274 | */ |
| 2275 | if (sc.nr_reclaimed < SWAP_CLUSTER_MAX) |
| 2276 | order = sc.order = 0; |
| 2277 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2278 | goto loop_again; |
| 2279 | } |
| 2280 | |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 2281 | return sc.nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2282 | } |
| 2283 | |
| 2284 | /* |
| 2285 | * The background pageout daemon, started as a kernel thread |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 2286 | * from the init process. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2287 | * |
| 2288 | * This basically trickles out pages so that we have _some_ |
| 2289 | * free memory available even if there is no other activity |
| 2290 | * that frees anything up. This is needed for things like routing |
| 2291 | * etc, where we otherwise might have all activity going on in |
| 2292 | * asynchronous contexts that cannot page things out. |
| 2293 | * |
| 2294 | * If there are applications that are active memory-allocators |
| 2295 | * (most normal use), this basically shouldn't matter. |
| 2296 | */ |
| 2297 | static int kswapd(void *p) |
| 2298 | { |
| 2299 | unsigned long order; |
| 2300 | pg_data_t *pgdat = (pg_data_t*)p; |
| 2301 | struct task_struct *tsk = current; |
| 2302 | DEFINE_WAIT(wait); |
| 2303 | struct reclaim_state reclaim_state = { |
| 2304 | .reclaimed_slab = 0, |
| 2305 | }; |
Rusty Russell | a70f730 | 2009-03-13 14:49:46 +1030 | [diff] [blame] | 2306 | const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2307 | |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 2308 | lockdep_set_current_reclaim_state(GFP_KERNEL); |
| 2309 | |
Rusty Russell | 174596a | 2009-01-01 10:12:29 +1030 | [diff] [blame] | 2310 | if (!cpumask_empty(cpumask)) |
Mike Travis | c5f59f0 | 2008-04-04 18:11:10 -0700 | [diff] [blame] | 2311 | set_cpus_allowed_ptr(tsk, cpumask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2312 | current->reclaim_state = &reclaim_state; |
| 2313 | |
| 2314 | /* |
| 2315 | * Tell the memory management that we're a "memory allocator", |
| 2316 | * and that if we need more memory we should get access to it |
| 2317 | * regardless (see "__alloc_pages()"). "kswapd" should |
| 2318 | * never get caught in the normal page freeing logic. |
| 2319 | * |
| 2320 | * (Kswapd normally doesn't need memory anyway, but sometimes |
| 2321 | * you need a small amount of memory in order to be able to |
| 2322 | * page out something else, and this flag essentially protects |
| 2323 | * us from recursively trying to free more memory as we're |
| 2324 | * trying to free the first piece of memory in the first place). |
| 2325 | */ |
Christoph Lameter | 930d915 | 2006-01-08 01:00:47 -0800 | [diff] [blame] | 2326 | tsk->flags |= PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD; |
Rafael J. Wysocki | 8314418 | 2007-07-17 04:03:35 -0700 | [diff] [blame] | 2327 | set_freezable(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2328 | |
| 2329 | order = 0; |
| 2330 | for ( ; ; ) { |
| 2331 | unsigned long new_order; |
David Rientjes | 8fe23e0 | 2009-12-14 17:58:33 -0800 | [diff] [blame] | 2332 | int ret; |
Christoph Lameter | 3e1d1d2 | 2005-06-24 23:13:50 -0700 | [diff] [blame] | 2333 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2334 | prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE); |
| 2335 | new_order = pgdat->kswapd_max_order; |
| 2336 | pgdat->kswapd_max_order = 0; |
| 2337 | if (order < new_order) { |
| 2338 | /* |
| 2339 | * Don't sleep if someone wants a larger 'order' |
| 2340 | * allocation |
| 2341 | */ |
| 2342 | order = new_order; |
| 2343 | } else { |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 2344 | if (!freezing(current) && !kthread_should_stop()) { |
| 2345 | long remaining = 0; |
| 2346 | |
| 2347 | /* Try to sleep for a short interval */ |
KOSAKI Motohiro | bb3ab59 | 2009-12-14 17:58:55 -0800 | [diff] [blame] | 2348 | if (!sleeping_prematurely(pgdat, order, remaining)) { |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 2349 | remaining = schedule_timeout(HZ/10); |
| 2350 | finish_wait(&pgdat->kswapd_wait, &wait); |
| 2351 | prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE); |
| 2352 | } |
| 2353 | |
| 2354 | /* |
| 2355 | * After a short sleep, check if it was a |
| 2356 | * premature sleep. If not, then go fully |
| 2357 | * to sleep until explicitly woken up |
| 2358 | */ |
Mel Gorman | 33906bc | 2010-08-09 17:19:16 -0700 | [diff] [blame] | 2359 | if (!sleeping_prematurely(pgdat, order, remaining)) { |
| 2360 | trace_mm_vmscan_kswapd_sleep(pgdat->node_id); |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 2361 | schedule(); |
Mel Gorman | 33906bc | 2010-08-09 17:19:16 -0700 | [diff] [blame] | 2362 | } else { |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 2363 | if (remaining) |
KOSAKI Motohiro | bb3ab59 | 2009-12-14 17:58:55 -0800 | [diff] [blame] | 2364 | count_vm_event(KSWAPD_LOW_WMARK_HIT_QUICKLY); |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 2365 | else |
KOSAKI Motohiro | bb3ab59 | 2009-12-14 17:58:55 -0800 | [diff] [blame] | 2366 | count_vm_event(KSWAPD_HIGH_WMARK_HIT_QUICKLY); |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 2367 | } |
| 2368 | } |
Rafael J. Wysocki | b1296cc | 2007-05-06 14:50:48 -0700 | [diff] [blame] | 2369 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2370 | order = pgdat->kswapd_max_order; |
| 2371 | } |
| 2372 | finish_wait(&pgdat->kswapd_wait, &wait); |
| 2373 | |
David Rientjes | 8fe23e0 | 2009-12-14 17:58:33 -0800 | [diff] [blame] | 2374 | ret = try_to_freeze(); |
| 2375 | if (kthread_should_stop()) |
| 2376 | break; |
| 2377 | |
| 2378 | /* |
| 2379 | * We can speed up thawing tasks if we don't call balance_pgdat |
| 2380 | * after returning from the refrigerator |
| 2381 | */ |
Mel Gorman | 33906bc | 2010-08-09 17:19:16 -0700 | [diff] [blame] | 2382 | if (!ret) { |
| 2383 | trace_mm_vmscan_kswapd_wake(pgdat->node_id, order); |
Rafael J. Wysocki | b1296cc | 2007-05-06 14:50:48 -0700 | [diff] [blame] | 2384 | balance_pgdat(pgdat, order); |
Mel Gorman | 33906bc | 2010-08-09 17:19:16 -0700 | [diff] [blame] | 2385 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2386 | } |
| 2387 | return 0; |
| 2388 | } |
| 2389 | |
| 2390 | /* |
| 2391 | * A zone is low on free memory, so wake its kswapd task to service it. |
| 2392 | */ |
| 2393 | void wakeup_kswapd(struct zone *zone, int order) |
| 2394 | { |
| 2395 | pg_data_t *pgdat; |
| 2396 | |
Con Kolivas | f3fe651 | 2006-01-06 00:11:15 -0800 | [diff] [blame] | 2397 | if (!populated_zone(zone)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2398 | return; |
| 2399 | |
| 2400 | pgdat = zone->zone_pgdat; |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 2401 | if (zone_watermark_ok(zone, order, low_wmark_pages(zone), 0, 0)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2402 | return; |
| 2403 | if (pgdat->kswapd_max_order < order) |
| 2404 | pgdat->kswapd_max_order = order; |
Mel Gorman | 33906bc | 2010-08-09 17:19:16 -0700 | [diff] [blame] | 2405 | trace_mm_vmscan_wakeup_kswapd(pgdat->node_id, zone_idx(zone), order); |
Paul Jackson | 02a0e53 | 2006-12-13 00:34:25 -0800 | [diff] [blame] | 2406 | if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2407 | return; |
Con Kolivas | 8d0986e | 2005-09-13 01:25:07 -0700 | [diff] [blame] | 2408 | if (!waitqueue_active(&pgdat->kswapd_wait)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2409 | return; |
Con Kolivas | 8d0986e | 2005-09-13 01:25:07 -0700 | [diff] [blame] | 2410 | wake_up_interruptible(&pgdat->kswapd_wait); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2411 | } |
| 2412 | |
Wu Fengguang | adea02a | 2009-09-21 17:01:42 -0700 | [diff] [blame] | 2413 | /* |
| 2414 | * The reclaimable count would be mostly accurate. |
| 2415 | * The less reclaimable pages may be |
| 2416 | * - mlocked pages, which will be moved to unevictable list when encountered |
| 2417 | * - mapped pages, which may require several travels to be reclaimed |
| 2418 | * - dirty pages, which is not "instantly" reclaimable |
| 2419 | */ |
| 2420 | unsigned long global_reclaimable_pages(void) |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 2421 | { |
Wu Fengguang | adea02a | 2009-09-21 17:01:42 -0700 | [diff] [blame] | 2422 | int nr; |
| 2423 | |
| 2424 | nr = global_page_state(NR_ACTIVE_FILE) + |
| 2425 | global_page_state(NR_INACTIVE_FILE); |
| 2426 | |
| 2427 | if (nr_swap_pages > 0) |
| 2428 | nr += global_page_state(NR_ACTIVE_ANON) + |
| 2429 | global_page_state(NR_INACTIVE_ANON); |
| 2430 | |
| 2431 | return nr; |
| 2432 | } |
| 2433 | |
| 2434 | unsigned long zone_reclaimable_pages(struct zone *zone) |
| 2435 | { |
| 2436 | int nr; |
| 2437 | |
| 2438 | nr = zone_page_state(zone, NR_ACTIVE_FILE) + |
| 2439 | zone_page_state(zone, NR_INACTIVE_FILE); |
| 2440 | |
| 2441 | if (nr_swap_pages > 0) |
| 2442 | nr += zone_page_state(zone, NR_ACTIVE_ANON) + |
| 2443 | zone_page_state(zone, NR_INACTIVE_ANON); |
| 2444 | |
| 2445 | return nr; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 2446 | } |
| 2447 | |
Rafael J. Wysocki | c6f37f1 | 2009-05-24 22:16:31 +0200 | [diff] [blame] | 2448 | #ifdef CONFIG_HIBERNATION |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2449 | /* |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame] | 2450 | * 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] | 2451 | * freed pages. |
| 2452 | * |
| 2453 | * Rather than trying to age LRUs the aim is to preserve the overall |
| 2454 | * LRU order by reclaiming preferentially |
| 2455 | * inactive > active > active referenced > active mapped |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2456 | */ |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame] | 2457 | unsigned long shrink_all_memory(unsigned long nr_to_reclaim) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2458 | { |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2459 | struct reclaim_state reclaim_state; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2460 | struct scan_control sc = { |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame] | 2461 | .gfp_mask = GFP_HIGHUSER_MOVABLE, |
| 2462 | .may_swap = 1, |
| 2463 | .may_unmap = 1, |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2464 | .may_writepage = 1, |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame] | 2465 | .nr_to_reclaim = nr_to_reclaim, |
| 2466 | .hibernation_mode = 1, |
| 2467 | .swappiness = vm_swappiness, |
| 2468 | .order = 0, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2469 | }; |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame] | 2470 | struct zonelist * zonelist = node_zonelist(numa_node_id(), sc.gfp_mask); |
| 2471 | struct task_struct *p = current; |
| 2472 | unsigned long nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2473 | |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame] | 2474 | p->flags |= PF_MEMALLOC; |
| 2475 | lockdep_set_current_reclaim_state(sc.gfp_mask); |
| 2476 | reclaim_state.reclaimed_slab = 0; |
| 2477 | p->reclaim_state = &reclaim_state; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 2478 | |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame] | 2479 | nr_reclaimed = do_try_to_free_pages(zonelist, &sc); |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2480 | |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame] | 2481 | p->reclaim_state = NULL; |
| 2482 | lockdep_clear_current_reclaim_state(); |
| 2483 | p->flags &= ~PF_MEMALLOC; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2484 | |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame] | 2485 | return nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2486 | } |
Rafael J. Wysocki | c6f37f1 | 2009-05-24 22:16:31 +0200 | [diff] [blame] | 2487 | #endif /* CONFIG_HIBERNATION */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2488 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2489 | /* It's optimal to keep kswapds on the same CPUs as their memory, but |
| 2490 | not required for correctness. So if the last cpu in a node goes |
| 2491 | away, we get changed to run anywhere: as the first one comes back, |
| 2492 | restore their cpu bindings. */ |
Chandra Seetharaman | 9c7b216 | 2006-06-27 02:54:07 -0700 | [diff] [blame] | 2493 | static int __devinit cpu_callback(struct notifier_block *nfb, |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 2494 | unsigned long action, void *hcpu) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2495 | { |
Yasunori Goto | 58c0a4a | 2007-10-16 01:25:40 -0700 | [diff] [blame] | 2496 | int nid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2497 | |
Rafael J. Wysocki | 8bb7844 | 2007-05-09 02:35:10 -0700 | [diff] [blame] | 2498 | if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN) { |
Yasunori Goto | 58c0a4a | 2007-10-16 01:25:40 -0700 | [diff] [blame] | 2499 | for_each_node_state(nid, N_HIGH_MEMORY) { |
Mike Travis | c5f59f0 | 2008-04-04 18:11:10 -0700 | [diff] [blame] | 2500 | pg_data_t *pgdat = NODE_DATA(nid); |
Rusty Russell | a70f730 | 2009-03-13 14:49:46 +1030 | [diff] [blame] | 2501 | const struct cpumask *mask; |
| 2502 | |
| 2503 | mask = cpumask_of_node(pgdat->node_id); |
Mike Travis | c5f59f0 | 2008-04-04 18:11:10 -0700 | [diff] [blame] | 2504 | |
Rusty Russell | 3e59794 | 2009-01-01 10:12:24 +1030 | [diff] [blame] | 2505 | if (cpumask_any_and(cpu_online_mask, mask) < nr_cpu_ids) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2506 | /* One of our CPUs online: restore mask */ |
Mike Travis | c5f59f0 | 2008-04-04 18:11:10 -0700 | [diff] [blame] | 2507 | set_cpus_allowed_ptr(pgdat->kswapd, mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2508 | } |
| 2509 | } |
| 2510 | return NOTIFY_OK; |
| 2511 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2512 | |
Yasunori Goto | 3218ae1 | 2006-06-27 02:53:33 -0700 | [diff] [blame] | 2513 | /* |
| 2514 | * This kswapd start function will be called by init and node-hot-add. |
| 2515 | * On node-hot-add, kswapd will moved to proper cpus if cpus are hot-added. |
| 2516 | */ |
| 2517 | int kswapd_run(int nid) |
| 2518 | { |
| 2519 | pg_data_t *pgdat = NODE_DATA(nid); |
| 2520 | int ret = 0; |
| 2521 | |
| 2522 | if (pgdat->kswapd) |
| 2523 | return 0; |
| 2524 | |
| 2525 | pgdat->kswapd = kthread_run(kswapd, pgdat, "kswapd%d", nid); |
| 2526 | if (IS_ERR(pgdat->kswapd)) { |
| 2527 | /* failure at boot is fatal */ |
| 2528 | BUG_ON(system_state == SYSTEM_BOOTING); |
| 2529 | printk("Failed to start kswapd on node %d\n",nid); |
| 2530 | ret = -1; |
| 2531 | } |
| 2532 | return ret; |
| 2533 | } |
| 2534 | |
David Rientjes | 8fe23e0 | 2009-12-14 17:58:33 -0800 | [diff] [blame] | 2535 | /* |
| 2536 | * Called by memory hotplug when all memory in a node is offlined. |
| 2537 | */ |
| 2538 | void kswapd_stop(int nid) |
| 2539 | { |
| 2540 | struct task_struct *kswapd = NODE_DATA(nid)->kswapd; |
| 2541 | |
| 2542 | if (kswapd) |
| 2543 | kthread_stop(kswapd); |
| 2544 | } |
| 2545 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2546 | static int __init kswapd_init(void) |
| 2547 | { |
Yasunori Goto | 3218ae1 | 2006-06-27 02:53:33 -0700 | [diff] [blame] | 2548 | int nid; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 2549 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2550 | swap_setup(); |
Christoph Lameter | 9422ffb | 2007-10-16 01:25:31 -0700 | [diff] [blame] | 2551 | for_each_node_state(nid, N_HIGH_MEMORY) |
Yasunori Goto | 3218ae1 | 2006-06-27 02:53:33 -0700 | [diff] [blame] | 2552 | kswapd_run(nid); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2553 | hotcpu_notifier(cpu_callback, 0); |
| 2554 | return 0; |
| 2555 | } |
| 2556 | |
| 2557 | module_init(kswapd_init) |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2558 | |
| 2559 | #ifdef CONFIG_NUMA |
| 2560 | /* |
| 2561 | * Zone reclaim mode |
| 2562 | * |
| 2563 | * If non-zero call zone_reclaim when the number of free pages falls below |
| 2564 | * the watermarks. |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2565 | */ |
| 2566 | int zone_reclaim_mode __read_mostly; |
| 2567 | |
Christoph Lameter | 1b2ffb7 | 2006-02-01 03:05:34 -0800 | [diff] [blame] | 2568 | #define RECLAIM_OFF 0 |
Fernando Luis Vazquez Cao | 7d03431 | 2008-07-29 22:33:41 -0700 | [diff] [blame] | 2569 | #define RECLAIM_ZONE (1<<0) /* Run shrink_inactive_list on the zone */ |
Christoph Lameter | 1b2ffb7 | 2006-02-01 03:05:34 -0800 | [diff] [blame] | 2570 | #define RECLAIM_WRITE (1<<1) /* Writeout pages during reclaim */ |
| 2571 | #define RECLAIM_SWAP (1<<2) /* Swap pages out during reclaim */ |
| 2572 | |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2573 | /* |
Christoph Lameter | a92f712 | 2006-02-01 03:05:32 -0800 | [diff] [blame] | 2574 | * Priority for ZONE_RECLAIM. This determines the fraction of pages |
| 2575 | * of a node considered for each zone_reclaim. 4 scans 1/16th of |
| 2576 | * a zone. |
| 2577 | */ |
| 2578 | #define ZONE_RECLAIM_PRIORITY 4 |
| 2579 | |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2580 | /* |
Christoph Lameter | 9614634 | 2006-07-03 00:24:13 -0700 | [diff] [blame] | 2581 | * Percentage of pages in a zone that must be unmapped for zone_reclaim to |
| 2582 | * occur. |
| 2583 | */ |
| 2584 | int sysctl_min_unmapped_ratio = 1; |
| 2585 | |
| 2586 | /* |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2587 | * If the number of slab pages in a zone grows beyond this percentage then |
| 2588 | * slab reclaim needs to occur. |
| 2589 | */ |
| 2590 | int sysctl_min_slab_ratio = 5; |
| 2591 | |
Mel Gorman | 90afa5d | 2009-06-16 15:33:20 -0700 | [diff] [blame] | 2592 | static inline unsigned long zone_unmapped_file_pages(struct zone *zone) |
| 2593 | { |
| 2594 | unsigned long file_mapped = zone_page_state(zone, NR_FILE_MAPPED); |
| 2595 | unsigned long file_lru = zone_page_state(zone, NR_INACTIVE_FILE) + |
| 2596 | zone_page_state(zone, NR_ACTIVE_FILE); |
| 2597 | |
| 2598 | /* |
| 2599 | * It's possible for there to be more file mapped pages than |
| 2600 | * accounted for by the pages on the file LRU lists because |
| 2601 | * tmpfs pages accounted for as ANON can also be FILE_MAPPED |
| 2602 | */ |
| 2603 | return (file_lru > file_mapped) ? (file_lru - file_mapped) : 0; |
| 2604 | } |
| 2605 | |
| 2606 | /* Work out how many page cache pages we can reclaim in this reclaim_mode */ |
| 2607 | static long zone_pagecache_reclaimable(struct zone *zone) |
| 2608 | { |
| 2609 | long nr_pagecache_reclaimable; |
| 2610 | long delta = 0; |
| 2611 | |
| 2612 | /* |
| 2613 | * If RECLAIM_SWAP is set, then all file pages are considered |
| 2614 | * potentially reclaimable. Otherwise, we have to worry about |
| 2615 | * pages like swapcache and zone_unmapped_file_pages() provides |
| 2616 | * a better estimate |
| 2617 | */ |
| 2618 | if (zone_reclaim_mode & RECLAIM_SWAP) |
| 2619 | nr_pagecache_reclaimable = zone_page_state(zone, NR_FILE_PAGES); |
| 2620 | else |
| 2621 | nr_pagecache_reclaimable = zone_unmapped_file_pages(zone); |
| 2622 | |
| 2623 | /* If we can't clean pages, remove dirty pages from consideration */ |
| 2624 | if (!(zone_reclaim_mode & RECLAIM_WRITE)) |
| 2625 | delta += zone_page_state(zone, NR_FILE_DIRTY); |
| 2626 | |
| 2627 | /* Watch for any possible underflows due to delta */ |
| 2628 | if (unlikely(delta > nr_pagecache_reclaimable)) |
| 2629 | delta = nr_pagecache_reclaimable; |
| 2630 | |
| 2631 | return nr_pagecache_reclaimable - delta; |
| 2632 | } |
| 2633 | |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2634 | /* |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2635 | * Try to free up some pages from this zone through reclaim. |
| 2636 | */ |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2637 | 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] | 2638 | { |
Christoph Lameter | 7fb2d46 | 2006-03-22 00:08:22 -0800 | [diff] [blame] | 2639 | /* Minimum pages needed in order to stay on node */ |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 2640 | const unsigned long nr_pages = 1 << order; |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2641 | struct task_struct *p = current; |
| 2642 | struct reclaim_state reclaim_state; |
Christoph Lameter | 8695949 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2643 | int priority; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2644 | struct scan_control sc = { |
| 2645 | .may_writepage = !!(zone_reclaim_mode & RECLAIM_WRITE), |
Johannes Weiner | a6dc60f8 | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 2646 | .may_unmap = !!(zone_reclaim_mode & RECLAIM_SWAP), |
KOSAKI Motohiro | 2e2e425 | 2009-04-21 12:24:57 -0700 | [diff] [blame] | 2647 | .may_swap = 1, |
KOSAKI Motohiro | 22fba33 | 2009-12-14 17:59:10 -0800 | [diff] [blame] | 2648 | .nr_to_reclaim = max_t(unsigned long, nr_pages, |
| 2649 | SWAP_CLUSTER_MAX), |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2650 | .gfp_mask = gfp_mask, |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2651 | .swappiness = vm_swappiness, |
Johannes Weiner | bd2f619 | 2009-03-31 15:19:38 -0700 | [diff] [blame] | 2652 | .order = order, |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2653 | }; |
KOSAKI Motohiro | 1574804 | 2010-08-09 17:19:50 -0700 | [diff] [blame] | 2654 | unsigned long nr_slab_pages0, nr_slab_pages1; |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2655 | |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2656 | cond_resched(); |
Christoph Lameter | d4f7796 | 2006-02-24 13:04:22 -0800 | [diff] [blame] | 2657 | /* |
| 2658 | * We need to be able to allocate from the reserves for RECLAIM_SWAP |
| 2659 | * and we also need to be able to write out pages for RECLAIM_WRITE |
| 2660 | * and RECLAIM_SWAP. |
| 2661 | */ |
| 2662 | p->flags |= PF_MEMALLOC | PF_SWAPWRITE; |
KOSAKI Motohiro | 76ca542 | 2010-03-05 13:41:47 -0800 | [diff] [blame] | 2663 | lockdep_set_current_reclaim_state(gfp_mask); |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2664 | reclaim_state.reclaimed_slab = 0; |
| 2665 | p->reclaim_state = &reclaim_state; |
Christoph Lameter | c84db23 | 2006-02-01 03:05:29 -0800 | [diff] [blame] | 2666 | |
Mel Gorman | 90afa5d | 2009-06-16 15:33:20 -0700 | [diff] [blame] | 2667 | if (zone_pagecache_reclaimable(zone) > zone->min_unmapped_pages) { |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2668 | /* |
| 2669 | * Free memory by calling shrink zone with increasing |
| 2670 | * priorities until we have enough memory freed. |
| 2671 | */ |
| 2672 | priority = ZONE_RECLAIM_PRIORITY; |
| 2673 | do { |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 2674 | shrink_zone(priority, zone, &sc); |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2675 | priority--; |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 2676 | } while (priority >= 0 && sc.nr_reclaimed < nr_pages); |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2677 | } |
Christoph Lameter | c84db23 | 2006-02-01 03:05:29 -0800 | [diff] [blame] | 2678 | |
KOSAKI Motohiro | 1574804 | 2010-08-09 17:19:50 -0700 | [diff] [blame] | 2679 | nr_slab_pages0 = zone_page_state(zone, NR_SLAB_RECLAIMABLE); |
| 2680 | if (nr_slab_pages0 > zone->min_slab_pages) { |
Christoph Lameter | 2a16e3f | 2006-02-01 03:05:35 -0800 | [diff] [blame] | 2681 | /* |
Christoph Lameter | 7fb2d46 | 2006-03-22 00:08:22 -0800 | [diff] [blame] | 2682 | * shrink_slab() does not currently allow us to determine how |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2683 | * many pages were freed in this zone. So we take the current |
| 2684 | * number of slab pages and shake the slab until it is reduced |
| 2685 | * by the same nr_pages that we used for reclaiming unmapped |
| 2686 | * pages. |
Christoph Lameter | 2a16e3f | 2006-02-01 03:05:35 -0800 | [diff] [blame] | 2687 | * |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2688 | * Note that shrink_slab will free memory on all zones and may |
| 2689 | * take a long time. |
Christoph Lameter | 2a16e3f | 2006-02-01 03:05:35 -0800 | [diff] [blame] | 2690 | */ |
KOSAKI Motohiro | 4dc4b3d | 2010-08-09 17:19:54 -0700 | [diff] [blame] | 2691 | for (;;) { |
| 2692 | unsigned long lru_pages = zone_reclaimable_pages(zone); |
| 2693 | |
| 2694 | /* No reclaimable slab or very low memory pressure */ |
| 2695 | if (!shrink_slab(sc.nr_scanned, gfp_mask, lru_pages)) |
| 2696 | break; |
| 2697 | |
| 2698 | /* Freed enough memory */ |
| 2699 | nr_slab_pages1 = zone_page_state(zone, |
| 2700 | NR_SLAB_RECLAIMABLE); |
| 2701 | if (nr_slab_pages1 + nr_pages <= nr_slab_pages0) |
| 2702 | break; |
| 2703 | } |
Christoph Lameter | 83e33a4 | 2006-09-25 23:31:53 -0700 | [diff] [blame] | 2704 | |
| 2705 | /* |
| 2706 | * Update nr_reclaimed by the number of slab pages we |
| 2707 | * reclaimed from this zone. |
| 2708 | */ |
KOSAKI Motohiro | 1574804 | 2010-08-09 17:19:50 -0700 | [diff] [blame] | 2709 | nr_slab_pages1 = zone_page_state(zone, NR_SLAB_RECLAIMABLE); |
| 2710 | if (nr_slab_pages1 < nr_slab_pages0) |
| 2711 | sc.nr_reclaimed += nr_slab_pages0 - nr_slab_pages1; |
Christoph Lameter | 2a16e3f | 2006-02-01 03:05:35 -0800 | [diff] [blame] | 2712 | } |
| 2713 | |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2714 | p->reclaim_state = NULL; |
Christoph Lameter | d4f7796 | 2006-02-24 13:04:22 -0800 | [diff] [blame] | 2715 | current->flags &= ~(PF_MEMALLOC | PF_SWAPWRITE); |
KOSAKI Motohiro | 76ca542 | 2010-03-05 13:41:47 -0800 | [diff] [blame] | 2716 | lockdep_clear_current_reclaim_state(); |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 2717 | return sc.nr_reclaimed >= nr_pages; |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2718 | } |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2719 | |
| 2720 | int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) |
| 2721 | { |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2722 | int node_id; |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2723 | int ret; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2724 | |
| 2725 | /* |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2726 | * Zone reclaim reclaims unmapped file backed pages and |
| 2727 | * slab pages if we are over the defined limits. |
Christoph Lameter | 34aa133 | 2006-06-30 01:55:37 -0700 | [diff] [blame] | 2728 | * |
Christoph Lameter | 9614634 | 2006-07-03 00:24:13 -0700 | [diff] [blame] | 2729 | * A small portion of unmapped file backed pages is needed for |
| 2730 | * file I/O otherwise pages read by file I/O will be immediately |
| 2731 | * thrown out if the zone is overallocated. So we do not reclaim |
| 2732 | * if less than a specified percentage of the zone is used by |
| 2733 | * unmapped file backed pages. |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2734 | */ |
Mel Gorman | 90afa5d | 2009-06-16 15:33:20 -0700 | [diff] [blame] | 2735 | if (zone_pagecache_reclaimable(zone) <= zone->min_unmapped_pages && |
| 2736 | zone_page_state(zone, NR_SLAB_RECLAIMABLE) <= zone->min_slab_pages) |
Mel Gorman | fa5e084 | 2009-06-16 15:33:22 -0700 | [diff] [blame] | 2737 | return ZONE_RECLAIM_FULL; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2738 | |
KOSAKI Motohiro | 93e4a89 | 2010-03-05 13:41:55 -0800 | [diff] [blame] | 2739 | if (zone->all_unreclaimable) |
Mel Gorman | fa5e084 | 2009-06-16 15:33:22 -0700 | [diff] [blame] | 2740 | return ZONE_RECLAIM_FULL; |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2741 | |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2742 | /* |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2743 | * Do not scan if the allocation should not be delayed. |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2744 | */ |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2745 | if (!(gfp_mask & __GFP_WAIT) || (current->flags & PF_MEMALLOC)) |
Mel Gorman | fa5e084 | 2009-06-16 15:33:22 -0700 | [diff] [blame] | 2746 | return ZONE_RECLAIM_NOSCAN; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2747 | |
| 2748 | /* |
| 2749 | * Only run zone reclaim on the local zone or on zones that do not |
| 2750 | * have associated processors. This will favor the local processor |
| 2751 | * over remote processors and spread off node memory allocations |
| 2752 | * as wide as possible. |
| 2753 | */ |
Christoph Lameter | 89fa302 | 2006-09-25 23:31:55 -0700 | [diff] [blame] | 2754 | node_id = zone_to_nid(zone); |
Christoph Lameter | 37c0708 | 2007-10-16 01:25:36 -0700 | [diff] [blame] | 2755 | if (node_state(node_id, N_CPU) && node_id != numa_node_id()) |
Mel Gorman | fa5e084 | 2009-06-16 15:33:22 -0700 | [diff] [blame] | 2756 | return ZONE_RECLAIM_NOSCAN; |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2757 | |
| 2758 | if (zone_test_and_set_flag(zone, ZONE_RECLAIM_LOCKED)) |
Mel Gorman | fa5e084 | 2009-06-16 15:33:22 -0700 | [diff] [blame] | 2759 | return ZONE_RECLAIM_NOSCAN; |
| 2760 | |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2761 | ret = __zone_reclaim(zone, gfp_mask, order); |
| 2762 | zone_clear_flag(zone, ZONE_RECLAIM_LOCKED); |
| 2763 | |
Mel Gorman | 24cf72518 | 2009-06-16 15:33:23 -0700 | [diff] [blame] | 2764 | if (!ret) |
| 2765 | count_vm_event(PGSCAN_ZONE_RECLAIM_FAILED); |
| 2766 | |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2767 | return ret; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2768 | } |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2769 | #endif |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 2770 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 2771 | /* |
| 2772 | * page_evictable - test whether a page is evictable |
| 2773 | * @page: the page to test |
| 2774 | * @vma: the VMA in which the page is or will be mapped, may be NULL |
| 2775 | * |
| 2776 | * Test whether page is evictable--i.e., should be placed on active/inactive |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 2777 | * lists vs unevictable list. The vma argument is !NULL when called from the |
| 2778 | * fault path to determine how to instantate a new page. |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 2779 | * |
| 2780 | * Reasons page might not be evictable: |
Lee Schermerhorn | ba9ddf4 | 2008-10-18 20:26:42 -0700 | [diff] [blame] | 2781 | * (1) page's mapping marked unevictable |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 2782 | * (2) page is part of an mlocked VMA |
Lee Schermerhorn | ba9ddf4 | 2008-10-18 20:26:42 -0700 | [diff] [blame] | 2783 | * |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 2784 | */ |
| 2785 | int page_evictable(struct page *page, struct vm_area_struct *vma) |
| 2786 | { |
| 2787 | |
Lee Schermerhorn | ba9ddf4 | 2008-10-18 20:26:42 -0700 | [diff] [blame] | 2788 | if (mapping_unevictable(page_mapping(page))) |
| 2789 | return 0; |
| 2790 | |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 2791 | if (PageMlocked(page) || (vma && is_mlocked_vma(vma, page))) |
| 2792 | return 0; |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 2793 | |
| 2794 | return 1; |
| 2795 | } |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 2796 | |
| 2797 | /** |
| 2798 | * check_move_unevictable_page - check page for evictability and move to appropriate zone lru list |
| 2799 | * @page: page to check evictability and move to appropriate lru list |
| 2800 | * @zone: zone page is in |
| 2801 | * |
| 2802 | * Checks a page for evictability and moves the page to the appropriate |
| 2803 | * zone lru list. |
| 2804 | * |
| 2805 | * Restrictions: zone->lru_lock must be held, page must be on LRU and must |
| 2806 | * have PageUnevictable set. |
| 2807 | */ |
| 2808 | static void check_move_unevictable_page(struct page *page, struct zone *zone) |
| 2809 | { |
| 2810 | VM_BUG_ON(PageActive(page)); |
| 2811 | |
| 2812 | retry: |
| 2813 | ClearPageUnevictable(page); |
| 2814 | if (page_evictable(page, NULL)) { |
Johannes Weiner | 401a8e1 | 2009-09-21 17:02:58 -0700 | [diff] [blame] | 2815 | enum lru_list l = page_lru_base_type(page); |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 2816 | |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 2817 | __dec_zone_state(zone, NR_UNEVICTABLE); |
| 2818 | list_move(&page->lru, &zone->lru[l].list); |
KAMEZAWA Hiroyuki | 08e552c | 2009-01-07 18:08:01 -0800 | [diff] [blame] | 2819 | mem_cgroup_move_lists(page, LRU_UNEVICTABLE, l); |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 2820 | __inc_zone_state(zone, NR_INACTIVE_ANON + l); |
| 2821 | __count_vm_event(UNEVICTABLE_PGRESCUED); |
| 2822 | } else { |
| 2823 | /* |
| 2824 | * rotate unevictable list |
| 2825 | */ |
| 2826 | SetPageUnevictable(page); |
| 2827 | list_move(&page->lru, &zone->lru[LRU_UNEVICTABLE].list); |
KAMEZAWA Hiroyuki | 08e552c | 2009-01-07 18:08:01 -0800 | [diff] [blame] | 2828 | mem_cgroup_rotate_lru_list(page, LRU_UNEVICTABLE); |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 2829 | if (page_evictable(page, NULL)) |
| 2830 | goto retry; |
| 2831 | } |
| 2832 | } |
| 2833 | |
| 2834 | /** |
| 2835 | * scan_mapping_unevictable_pages - scan an address space for evictable pages |
| 2836 | * @mapping: struct address_space to scan for evictable pages |
| 2837 | * |
| 2838 | * Scan all pages in mapping. Check unevictable pages for |
| 2839 | * evictability and move them to the appropriate zone lru list. |
| 2840 | */ |
| 2841 | void scan_mapping_unevictable_pages(struct address_space *mapping) |
| 2842 | { |
| 2843 | pgoff_t next = 0; |
| 2844 | pgoff_t end = (i_size_read(mapping->host) + PAGE_CACHE_SIZE - 1) >> |
| 2845 | PAGE_CACHE_SHIFT; |
| 2846 | struct zone *zone; |
| 2847 | struct pagevec pvec; |
| 2848 | |
| 2849 | if (mapping->nrpages == 0) |
| 2850 | return; |
| 2851 | |
| 2852 | pagevec_init(&pvec, 0); |
| 2853 | while (next < end && |
| 2854 | pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { |
| 2855 | int i; |
| 2856 | int pg_scanned = 0; |
| 2857 | |
| 2858 | zone = NULL; |
| 2859 | |
| 2860 | for (i = 0; i < pagevec_count(&pvec); i++) { |
| 2861 | struct page *page = pvec.pages[i]; |
| 2862 | pgoff_t page_index = page->index; |
| 2863 | struct zone *pagezone = page_zone(page); |
| 2864 | |
| 2865 | pg_scanned++; |
| 2866 | if (page_index > next) |
| 2867 | next = page_index; |
| 2868 | next++; |
| 2869 | |
| 2870 | if (pagezone != zone) { |
| 2871 | if (zone) |
| 2872 | spin_unlock_irq(&zone->lru_lock); |
| 2873 | zone = pagezone; |
| 2874 | spin_lock_irq(&zone->lru_lock); |
| 2875 | } |
| 2876 | |
| 2877 | if (PageLRU(page) && PageUnevictable(page)) |
| 2878 | check_move_unevictable_page(page, zone); |
| 2879 | } |
| 2880 | if (zone) |
| 2881 | spin_unlock_irq(&zone->lru_lock); |
| 2882 | pagevec_release(&pvec); |
| 2883 | |
| 2884 | count_vm_events(UNEVICTABLE_PGSCANNED, pg_scanned); |
| 2885 | } |
| 2886 | |
| 2887 | } |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 2888 | |
| 2889 | /** |
| 2890 | * scan_zone_unevictable_pages - check unevictable list for evictable pages |
| 2891 | * @zone - zone of which to scan the unevictable list |
| 2892 | * |
| 2893 | * Scan @zone's unevictable LRU lists to check for pages that have become |
| 2894 | * evictable. Move those that have to @zone's inactive list where they |
| 2895 | * become candidates for reclaim, unless shrink_inactive_zone() decides |
| 2896 | * to reactivate them. Pages that are still unevictable are rotated |
| 2897 | * back onto @zone's unevictable list. |
| 2898 | */ |
| 2899 | #define SCAN_UNEVICTABLE_BATCH_SIZE 16UL /* arbitrary lock hold batch size */ |
KOSAKI Motohiro | 14b90b2 | 2009-01-06 14:39:45 -0800 | [diff] [blame] | 2900 | static void scan_zone_unevictable_pages(struct zone *zone) |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 2901 | { |
| 2902 | struct list_head *l_unevictable = &zone->lru[LRU_UNEVICTABLE].list; |
| 2903 | unsigned long scan; |
| 2904 | unsigned long nr_to_scan = zone_page_state(zone, NR_UNEVICTABLE); |
| 2905 | |
| 2906 | while (nr_to_scan > 0) { |
| 2907 | unsigned long batch_size = min(nr_to_scan, |
| 2908 | SCAN_UNEVICTABLE_BATCH_SIZE); |
| 2909 | |
| 2910 | spin_lock_irq(&zone->lru_lock); |
| 2911 | for (scan = 0; scan < batch_size; scan++) { |
| 2912 | struct page *page = lru_to_page(l_unevictable); |
| 2913 | |
| 2914 | if (!trylock_page(page)) |
| 2915 | continue; |
| 2916 | |
| 2917 | prefetchw_prev_lru_page(page, l_unevictable, flags); |
| 2918 | |
| 2919 | if (likely(PageLRU(page) && PageUnevictable(page))) |
| 2920 | check_move_unevictable_page(page, zone); |
| 2921 | |
| 2922 | unlock_page(page); |
| 2923 | } |
| 2924 | spin_unlock_irq(&zone->lru_lock); |
| 2925 | |
| 2926 | nr_to_scan -= batch_size; |
| 2927 | } |
| 2928 | } |
| 2929 | |
| 2930 | |
| 2931 | /** |
| 2932 | * scan_all_zones_unevictable_pages - scan all unevictable lists for evictable pages |
| 2933 | * |
| 2934 | * A really big hammer: scan all zones' unevictable LRU lists to check for |
| 2935 | * pages that have become evictable. Move those back to the zones' |
| 2936 | * inactive list where they become candidates for reclaim. |
| 2937 | * This occurs when, e.g., we have unswappable pages on the unevictable lists, |
| 2938 | * and we add swap to the system. As such, it runs in the context of a task |
| 2939 | * that has possibly/probably made some previously unevictable pages |
| 2940 | * evictable. |
| 2941 | */ |
KOSAKI Motohiro | ff30153 | 2009-01-06 14:39:44 -0800 | [diff] [blame] | 2942 | static void scan_all_zones_unevictable_pages(void) |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 2943 | { |
| 2944 | struct zone *zone; |
| 2945 | |
| 2946 | for_each_zone(zone) { |
| 2947 | scan_zone_unevictable_pages(zone); |
| 2948 | } |
| 2949 | } |
| 2950 | |
| 2951 | /* |
| 2952 | * scan_unevictable_pages [vm] sysctl handler. On demand re-scan of |
| 2953 | * all nodes' unevictable lists for evictable pages |
| 2954 | */ |
| 2955 | unsigned long scan_unevictable_pages; |
| 2956 | |
| 2957 | int scan_unevictable_handler(struct ctl_table *table, int write, |
Alexey Dobriyan | 8d65af7 | 2009-09-23 15:57:19 -0700 | [diff] [blame] | 2958 | void __user *buffer, |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 2959 | size_t *length, loff_t *ppos) |
| 2960 | { |
Alexey Dobriyan | 8d65af7 | 2009-09-23 15:57:19 -0700 | [diff] [blame] | 2961 | proc_doulongvec_minmax(table, write, buffer, length, ppos); |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 2962 | |
| 2963 | if (write && *(unsigned long *)table->data) |
| 2964 | scan_all_zones_unevictable_pages(); |
| 2965 | |
| 2966 | scan_unevictable_pages = 0; |
| 2967 | return 0; |
| 2968 | } |
| 2969 | |
| 2970 | /* |
| 2971 | * per node 'scan_unevictable_pages' attribute. On demand re-scan of |
| 2972 | * a specified node's per zone unevictable lists for evictable pages. |
| 2973 | */ |
| 2974 | |
| 2975 | static ssize_t read_scan_unevictable_node(struct sys_device *dev, |
| 2976 | struct sysdev_attribute *attr, |
| 2977 | char *buf) |
| 2978 | { |
| 2979 | return sprintf(buf, "0\n"); /* always zero; should fit... */ |
| 2980 | } |
| 2981 | |
| 2982 | static ssize_t write_scan_unevictable_node(struct sys_device *dev, |
| 2983 | struct sysdev_attribute *attr, |
| 2984 | const char *buf, size_t count) |
| 2985 | { |
| 2986 | struct zone *node_zones = NODE_DATA(dev->id)->node_zones; |
| 2987 | struct zone *zone; |
| 2988 | unsigned long res; |
| 2989 | unsigned long req = strict_strtoul(buf, 10, &res); |
| 2990 | |
| 2991 | if (!req) |
| 2992 | return 1; /* zero is no-op */ |
| 2993 | |
| 2994 | for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) { |
| 2995 | if (!populated_zone(zone)) |
| 2996 | continue; |
| 2997 | scan_zone_unevictable_pages(zone); |
| 2998 | } |
| 2999 | return 1; |
| 3000 | } |
| 3001 | |
| 3002 | |
| 3003 | static SYSDEV_ATTR(scan_unevictable_pages, S_IRUGO | S_IWUSR, |
| 3004 | read_scan_unevictable_node, |
| 3005 | write_scan_unevictable_node); |
| 3006 | |
| 3007 | int scan_unevictable_register_node(struct node *node) |
| 3008 | { |
| 3009 | return sysdev_create_file(&node->sysdev, &attr_scan_unevictable_pages); |
| 3010 | } |
| 3011 | |
| 3012 | void scan_unevictable_unregister_node(struct node *node) |
| 3013 | { |
| 3014 | sysdev_remove_file(&node->sysdev, &attr_scan_unevictable_pages); |
| 3015 | } |
| 3016 | |