From 9786bf841da57fac3457a1dac41acb4c1f2eced6 Mon Sep 17 00:00:00 2001 From: Johannes Weiner Date: Tue, 31 Mar 2009 15:19:35 -0700 Subject: [PATCH] vmscan: clip swap_cluster_max in shrink_all_memory() shrink_inactive_list() scans in sc->swap_cluster_max chunks until it hits the scan limit it was passed. shrink_inactive_list() { do { isolate_pages(swap_cluster_max) shrink_page_list() } while (nr_scanned < max_scan); } This assumes that swap_cluster_max is not bigger than the scan limit because the latter is checked only after at least one iteration. In shrink_all_memory() sc->swap_cluster_max is initialized to the overall reclaim goal in the beginning but not decreased while reclaim is making progress which leads to subsequent calls to shrink_inactive_list() reclaiming way too much in the one iteration that is done unconditionally. Set sc->swap_cluster_max always to the proper goal before doing shrink_all_zones() shrink_list() shrink_inactive_list(). While the current shrink_all_memory() happily reclaims more than actually requested, this patch fixes it to never exceed the goal: unpatched wanted=10000 reclaimed=13356 wanted=10000 reclaimed=19711 wanted=10000 reclaimed=10289 wanted=10000 reclaimed=17306 wanted=10000 reclaimed=10700 wanted=10000 reclaimed=10004 wanted=10000 reclaimed=13301 wanted=10000 reclaimed=10976 wanted=10000 reclaimed=10605 wanted=10000 reclaimed=10088 wanted=10000 reclaimed=15000 patched wanted=10000 reclaimed=10000 wanted=10000 reclaimed=9599 wanted=10000 reclaimed=8476 wanted=10000 reclaimed=8326 wanted=10000 reclaimed=10000 wanted=10000 reclaimed=10000 wanted=10000 reclaimed=9919 wanted=10000 reclaimed=10000 wanted=10000 reclaimed=10000 wanted=10000 reclaimed=10000 wanted=10000 reclaimed=10000 wanted=10000 reclaimed=9624 wanted=10000 reclaimed=10000 wanted=10000 reclaimed=10000 wanted=8500 reclaimed=8092 wanted=316 reclaimed=316 Signed-off-by: Johannes Weiner Reviewed-by: MinChan Kim Acked-by: Nigel Cunningham Acked-by: "Rafael J. Wysocki" Reviewed-by: KOSAKI Motohiro Cc: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmscan.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index b15dcbb9e17..9578063cd94 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2109,7 +2109,6 @@ unsigned long shrink_all_memory(unsigned long nr_pages) struct scan_control sc = { .gfp_mask = GFP_KERNEL, .may_unmap = 0, - .swap_cluster_max = nr_pages, .may_writepage = 1, .isolate_pages = isolate_pages_global, }; @@ -2151,6 +2150,7 @@ unsigned long shrink_all_memory(unsigned long nr_pages) 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; -- 2.41.1