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authorKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>2009-12-14 17:59:12 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-12-15 08:53:18 -0800
commit7b51755c3b38483b574d363d5ee587283c3f7999 (patch)
tree29ac6d3b73f0a28488dabff03a7df948c0333906 /mm
parent22fba33545b731408deab6e96b6e231ee05fd10b (diff)
downloadop-kernel-dev-7b51755c3b38483b574d363d5ee587283c3f7999.zip
op-kernel-dev-7b51755c3b38483b574d363d5ee587283c3f7999.tar.gz
vmscan: kill hibernation specific reclaim logic and unify it
shrink_all_zone() was introduced by commit d6277db4ab (swsusp: rework memory shrinker) for hibernate performance improvement. and sc.swap_cluster_max was introduced by commit a06fe4d307 (Speed freeing memory for suspend). commit a06fe4d307 said Without the patch: Freed 14600 pages in 1749 jiffies = 32.61 MB/s (Anomolous!) Freed 88563 pages in 14719 jiffies = 23.50 MB/s Freed 205734 pages in 32389 jiffies = 24.81 MB/s With the patch: Freed 68252 pages in 496 jiffies = 537.52 MB/s Freed 116464 pages in 569 jiffies = 798.54 MB/s Freed 209699 pages in 705 jiffies = 1161.89 MB/s At that time, their patch was pretty worth. However, Modern Hardware trend and recent VM improvement broke its worth. From several reason, I think we should remove shrink_all_zones() at all. detail: 1) Old days, shrink_zone()'s slowness was mainly caused by stupid io-throttle at no i/o congestion. but current shrink_zone() is sane, not slow. 2) shrink_all_zone() try to shrink all pages at a time. but it doesn't works fine on numa system. example) System has 4GB memory and each node have 2GB. and hibernate need 1GB. optimal) steal 500MB from each node. shrink_all_zones) steal 1GB from node-0. Oh, Cache balancing logic was broken. ;) Unfortunately, Desktop system moved ahead NUMA at nowadays. (Side note, if hibernate require 2GB, shrink_all_zones() never success on above machine) 3) if the node has several I/O flighting pages, shrink_all_zones() makes pretty bad result. schenario) hibernate need 1GB 1) shrink_all_zones() try to reclaim 1GB from Node-0 2) but it only reclaimed 990MB 3) stupidly, shrink_all_zones() try to reclaim 1GB from Node-1 4) it reclaimed 990MB Oh, well. it reclaimed twice much than required. In the other hand, current shrink_zone() has sane baling out logic. then, it doesn't make overkill reclaim. then, we lost shrink_zones()'s risk. 4) SplitLRU VM always keep active/inactive ratio very carefully. inactive list only shrinking break its assumption. it makes unnecessary OOM risk. it obviously suboptimal. Now, shrink_all_memory() is only the wrapper function of do_try_to_free_pages(). it bring good reviewability and debuggability, and solve above problems. side note: Reclaim logic unificication makes two good side effect. - Fix recursive reclaim bug on shrink_all_memory(). it did forgot to use PF_MEMALLOC. it mean the system be able to stuck into deadlock. - Now, shrink_all_memory() got lockdep awareness. it bring good debuggability. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/vmscan.c153
1 files changed, 26 insertions, 127 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 7b0d5c7..63bd521 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -58,6 +58,8 @@ struct scan_control {
/* How many pages shrink_list() should reclaim */
unsigned long nr_to_reclaim;
+ unsigned long hibernation_mode;
+
/* This context's GFP mask */
gfp_t gfp_mask;
@@ -1796,7 +1798,8 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
}
/* Take a nap, wait for some writeback to complete */
- if (sc->nr_scanned && priority < DEF_PRIORITY - 2)
+ if (!sc->hibernation_mode && sc->nr_scanned &&
+ priority < DEF_PRIORITY - 2)
congestion_wait(BLK_RW_ASYNC, HZ/10);
}
/* top priority shrink_zones still had more to do? don't OOM, then */
@@ -2336,148 +2339,44 @@ unsigned long zone_reclaimable_pages(struct zone *zone)
#ifdef CONFIG_HIBERNATION
/*
- * Helper function for shrink_all_memory(). Tries to reclaim 'nr_pages' pages
- * from LRU lists system-wide, for given pass and priority.
- *
- * For pass > 3 we also try to shrink the LRU lists that contain a few pages
- */
-static void shrink_all_zones(unsigned long nr_pages, int prio,
- int pass, struct scan_control *sc)
-{
- struct zone *zone;
- unsigned long nr_reclaimed = 0;
- struct zone_reclaim_stat *reclaim_stat;
-
- for_each_populated_zone(zone) {
- enum lru_list l;
-
- if (zone_is_all_unreclaimable(zone) && prio != DEF_PRIORITY)
- continue;
-
- for_each_evictable_lru(l) {
- enum zone_stat_item ls = NR_LRU_BASE + l;
- unsigned long lru_pages = zone_page_state(zone, ls);
-
- /* For pass = 0, we don't shrink the active list */
- if (pass == 0 && (l == LRU_ACTIVE_ANON ||
- l == LRU_ACTIVE_FILE))
- continue;
-
- reclaim_stat = get_reclaim_stat(zone, sc);
- reclaim_stat->nr_saved_scan[l] +=
- (lru_pages >> prio) + 1;
- if (reclaim_stat->nr_saved_scan[l]
- >= nr_pages || pass > 3) {
- unsigned long nr_to_scan;
-
- reclaim_stat->nr_saved_scan[l] = 0;
- nr_to_scan = min(nr_pages, lru_pages);
- nr_reclaimed += shrink_list(l, nr_to_scan, zone,
- sc, prio);
- if (nr_reclaimed >= nr_pages) {
- sc->nr_reclaimed += nr_reclaimed;
- return;
- }
- }
- }
- }
- sc->nr_reclaimed += nr_reclaimed;
-}
-
-/*
- * Try to free `nr_pages' of memory, system-wide, and return the number of
+ * Try to free `nr_to_reclaim' of memory, system-wide, and return the number of
* freed pages.
*
* Rather than trying to age LRUs the aim is to preserve the overall
* LRU order by reclaiming preferentially
* inactive > active > active referenced > active mapped
*/
-unsigned long shrink_all_memory(unsigned long nr_pages)
+unsigned long shrink_all_memory(unsigned long nr_to_reclaim)
{
- unsigned long lru_pages, nr_slab;
- int pass;
struct reclaim_state reclaim_state;
struct scan_control sc = {
- .gfp_mask = GFP_KERNEL,
- .may_unmap = 0,
+ .gfp_mask = GFP_HIGHUSER_MOVABLE,
+ .may_swap = 1,
+ .may_unmap = 1,
.may_writepage = 1,
+ .swap_cluster_max = SWAP_CLUSTER_MAX,
+ .nr_to_reclaim = nr_to_reclaim,
+ .hibernation_mode = 1,
+ .swappiness = vm_swappiness,
+ .order = 0,
.isolate_pages = isolate_pages_global,
- .nr_reclaimed = 0,
};
+ struct zonelist * zonelist = node_zonelist(numa_node_id(), sc.gfp_mask);
+ struct task_struct *p = current;
+ unsigned long nr_reclaimed;
- current->reclaim_state = &reclaim_state;
-
- lru_pages = global_reclaimable_pages();
- nr_slab = global_page_state(NR_SLAB_RECLAIMABLE);
- /* If slab caches are huge, it's better to hit them first */
- while (nr_slab >= lru_pages) {
- reclaim_state.reclaimed_slab = 0;
- shrink_slab(nr_pages, sc.gfp_mask, lru_pages);
- if (!reclaim_state.reclaimed_slab)
- break;
-
- sc.nr_reclaimed += reclaim_state.reclaimed_slab;
- if (sc.nr_reclaimed >= nr_pages)
- goto out;
-
- nr_slab -= reclaim_state.reclaimed_slab;
- }
-
- /*
- * We try to shrink LRUs in 5 passes:
- * 0 = Reclaim from inactive_list only
- * 1 = Reclaim from active list but don't reclaim mapped
- * 2 = 2nd pass of type 1
- * 3 = Reclaim mapped (normal reclaim)
- * 4 = 2nd pass of type 3
- */
- for (pass = 0; pass < 5; pass++) {
- int prio;
-
- /* Force reclaiming mapped pages in the passes #3 and #4 */
- if (pass > 2)
- sc.may_unmap = 1;
-
- for (prio = DEF_PRIORITY; prio >= 0; prio--) {
- unsigned long nr_to_scan = nr_pages - sc.nr_reclaimed;
-
- sc.nr_scanned = 0;
- sc.swap_cluster_max = nr_to_scan;
- shrink_all_zones(nr_to_scan, prio, pass, &sc);
- if (sc.nr_reclaimed >= nr_pages)
- goto out;
-
- reclaim_state.reclaimed_slab = 0;
- shrink_slab(sc.nr_scanned, sc.gfp_mask,
- global_reclaimable_pages());
- sc.nr_reclaimed += reclaim_state.reclaimed_slab;
- if (sc.nr_reclaimed >= nr_pages)
- goto out;
-
- if (sc.nr_scanned && prio < DEF_PRIORITY - 2)
- congestion_wait(BLK_RW_ASYNC, HZ / 10);
- }
- }
-
- /*
- * If sc.nr_reclaimed = 0, we could not shrink LRUs, but there may be
- * something in slab caches
- */
- if (!sc.nr_reclaimed) {
- do {
- reclaim_state.reclaimed_slab = 0;
- shrink_slab(nr_pages, sc.gfp_mask,
- global_reclaimable_pages());
- sc.nr_reclaimed += reclaim_state.reclaimed_slab;
- } while (sc.nr_reclaimed < nr_pages &&
- reclaim_state.reclaimed_slab > 0);
- }
+ p->flags |= PF_MEMALLOC;
+ lockdep_set_current_reclaim_state(sc.gfp_mask);
+ reclaim_state.reclaimed_slab = 0;
+ p->reclaim_state = &reclaim_state;
+ nr_reclaimed = do_try_to_free_pages(zonelist, &sc);
-out:
- current->reclaim_state = NULL;
+ p->reclaim_state = NULL;
+ lockdep_clear_current_reclaim_state();
+ p->flags &= ~PF_MEMALLOC;
- return sc.nr_reclaimed;
+ return nr_reclaimed;
}
#endif /* CONFIG_HIBERNATION */
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