[PATCH] vmscan: scan_control cleanup
Initialise as much of scan_control as possible at the declaration site. This
tidies things up a bit and assures us that all unmentioned fields are zeroed
out.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/vmscan.c b/mm/vmscan.c
index f7c4f37..5feef4d 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1431,13 +1431,14 @@
int ret = 0;
int total_scanned = 0, total_reclaimed = 0;
struct reclaim_state *reclaim_state = current->reclaim_state;
- struct scan_control sc;
unsigned long lru_pages = 0;
int i;
-
- sc.gfp_mask = gfp_mask;
- sc.may_writepage = !laptop_mode;
- sc.may_swap = 1;
+ struct scan_control sc = {
+ .gfp_mask = gfp_mask,
+ .may_writepage = !laptop_mode,
+ .swap_cluster_max = SWAP_CLUSTER_MAX,
+ .may_swap = 1,
+ };
inc_page_state(allocstall);
@@ -1455,7 +1456,6 @@
sc.nr_mapped = read_page_state(nr_mapped);
sc.nr_scanned = 0;
sc.nr_reclaimed = 0;
- sc.swap_cluster_max = SWAP_CLUSTER_MAX;
if (!priority)
disable_swap_token();
shrink_caches(priority, zones, &sc);
@@ -1478,7 +1478,8 @@
* that's undesirable in laptop mode, where we *want* lumpy
* writeout. So in laptop mode, write out the whole world.
*/
- if (total_scanned > sc.swap_cluster_max + sc.swap_cluster_max/2) {
+ if (total_scanned > sc.swap_cluster_max +
+ sc.swap_cluster_max / 2) {
wakeup_pdflush(laptop_mode ? 0 : total_scanned);
sc.may_writepage = 1;
}
@@ -1532,14 +1533,16 @@
int i;
int total_scanned, total_reclaimed;
struct reclaim_state *reclaim_state = current->reclaim_state;
- struct scan_control sc;
+ struct scan_control sc = {
+ .gfp_mask = GFP_KERNEL,
+ .may_swap = 1,
+ .swap_cluster_max = nr_pages ? nr_pages : SWAP_CLUSTER_MAX,
+ };
loop_again:
total_scanned = 0;
total_reclaimed = 0;
- sc.gfp_mask = GFP_KERNEL;
- sc.may_writepage = !laptop_mode;
- sc.may_swap = 1;
+ sc.may_writepage = !laptop_mode,
sc.nr_mapped = read_page_state(nr_mapped);
inc_page_state(pageoutrun);
@@ -1621,7 +1624,6 @@
zone->prev_priority = priority;
sc.nr_scanned = 0;
sc.nr_reclaimed = 0;
- sc.swap_cluster_max = nr_pages? nr_pages : SWAP_CLUSTER_MAX;
shrink_zone(priority, zone, &sc);
reclaim_state->reclaimed_slab = 0;
nr_slab = shrink_slab(sc.nr_scanned, GFP_KERNEL,
@@ -1869,46 +1871,21 @@
/*
* Try to free up some pages from this zone through reclaim.
*/
-int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
+static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
{
- int nr_pages;
+ const int nr_pages = 1 << order;
struct task_struct *p = current;
struct reclaim_state reclaim_state;
- struct scan_control sc;
- cpumask_t mask;
- int node_id;
int priority;
-
- if (time_before(jiffies,
- zone->last_unsuccessful_zone_reclaim + zone_reclaim_interval))
- return 0;
-
- if (!(gfp_mask & __GFP_WAIT) ||
- zone->all_unreclaimable ||
- atomic_read(&zone->reclaim_in_progress) > 0 ||
- (p->flags & PF_MEMALLOC))
- return 0;
-
- node_id = zone->zone_pgdat->node_id;
- mask = node_to_cpumask(node_id);
- if (!cpus_empty(mask) && node_id != numa_node_id())
- return 0;
-
- sc.may_writepage = !!(zone_reclaim_mode & RECLAIM_WRITE);
- sc.may_swap = !!(zone_reclaim_mode & RECLAIM_SWAP);
- sc.nr_scanned = 0;
- sc.nr_reclaimed = 0;
- sc.nr_mapped = read_page_state(nr_mapped);
- sc.gfp_mask = gfp_mask;
+ struct scan_control sc = {
+ .may_writepage = !!(zone_reclaim_mode & RECLAIM_WRITE),
+ .may_swap = !!(zone_reclaim_mode & RECLAIM_SWAP),
+ .nr_mapped = read_page_state(nr_mapped),
+ .swap_cluster_max = max(nr_pages, SWAP_CLUSTER_MAX),
+ .gfp_mask = gfp_mask,
+ };
disable_swap_token();
-
- nr_pages = 1 << order;
- if (nr_pages > SWAP_CLUSTER_MAX)
- sc.swap_cluster_max = nr_pages;
- else
- sc.swap_cluster_max = SWAP_CLUSTER_MAX;
-
cond_resched();
/*
* We need to be able to allocate from the reserves for RECLAIM_SWAP
@@ -1949,5 +1926,44 @@
return sc.nr_reclaimed >= nr_pages;
}
+
+int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
+{
+ cpumask_t mask;
+ int node_id;
+
+ /*
+ * Do not reclaim if there was a recent unsuccessful attempt at zone
+ * reclaim. In that case we let allocations go off node for the
+ * zone_reclaim_interval. Otherwise we would scan for each off-node
+ * page allocation.
+ */
+ if (time_before(jiffies,
+ zone->last_unsuccessful_zone_reclaim + zone_reclaim_interval))
+ return 0;
+
+ /*
+ * Avoid concurrent zone reclaims, do not reclaim in a zone that does
+ * not have reclaimable pages and if we should not delay the allocation
+ * then do not scan.
+ */
+ if (!(gfp_mask & __GFP_WAIT) ||
+ zone->all_unreclaimable ||
+ atomic_read(&zone->reclaim_in_progress) > 0 ||
+ (current->flags & PF_MEMALLOC))
+ return 0;
+
+ /*
+ * Only run zone reclaim on the local zone or on zones that do not
+ * have associated processors. This will favor the local processor
+ * over remote processors and spread off node memory allocations
+ * as wide as possible.
+ */
+ node_id = zone->zone_pgdat->node_id;
+ mask = node_to_cpumask(node_id);
+ if (!cpus_empty(mask) && node_id != numa_node_id())
+ return 0;
+ return __zone_reclaim(zone, gfp_mask, order);
+}
#endif