From: Nick Piggin Date: Tue, 26 Sep 2006 06:31:28 +0000 (-0700) Subject: [PATCH] oom: reclaim_mapped on oom X-Git-Tag: v2.6.19-rc1~1189 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4ff1ffb4870b007b86f21e5f27eeb11498c4c077;p=linux-2.6 [PATCH] oom: reclaim_mapped on oom Potentially it takes several scans of the lru lists before we can even start reclaiming pages. mapped pages, with young ptes can take 2 passes on the active list + one on the inactive list. But reclaim_mapped may not always kick in instantly, so it could take even more than that. Raise the threshold for marking a zone as all_unreclaimable from a factor of 4 time the pages in the zone to 6. Introduce a mechanism to force reclaim_mapped if we've reached a factor 3 and still haven't made progress. Previously, a customer doing stress testing was able to easily OOM the box after using only a small fraction of its swap (~100MB). After the patches, it would only OOM after having used up all swap (~800MB). Signed-off-by: Nick Piggin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/vmscan.c b/mm/vmscan.c index ba18d0c36b..8f35d7d585 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -697,6 +697,11 @@ done: return nr_reclaimed; } +static inline int zone_is_near_oom(struct zone *zone) +{ + return zone->pages_scanned >= (zone->nr_active + zone->nr_inactive)*3; +} + /* * This moves pages from the active list to the inactive list. * @@ -732,6 +737,9 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone, long distress; long swap_tendency; + if (zone_is_near_oom(zone)) + goto force_reclaim_mapped; + /* * `distress' is a measure of how much trouble we're having * reclaiming pages. 0 -> no problems. 100 -> great trouble. @@ -767,6 +775,7 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone, * memory onto the inactive list. */ if (swap_tendency >= 100) +force_reclaim_mapped: reclaim_mapped = 1; } @@ -1161,7 +1170,7 @@ scan: if (zone->all_unreclaimable) continue; if (nr_slab == 0 && zone->pages_scanned >= - (zone->nr_active + zone->nr_inactive) * 4) + (zone->nr_active + zone->nr_inactive) * 6) zone->all_unreclaimable = 1; /* * If we've done a decent amount of scanning and