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authorKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>2011-06-27 19:18:12 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2011-06-27 21:00:13 -0400
commitac34a1a3c39da0a1b9188d12a9ce85506364ed2a (patch)
treef74f34047c6bc516e29196685cc8671aff4a02d2 /mm
parent26c4caea9d697043cc5a458b96411b86d7f6babd (diff)
memcg: fix direct softlimit reclaim to be called in limit path
Commit d149e3b25d7c ("memcg: add the soft_limit reclaim in global direct reclaim") adds a softlimit hook to shrink_zones(). By this, soft limit is called as try_to_free_pages() do_try_to_free_pages() shrink_zones() mem_cgroup_soft_limit_reclaim() Then, direct reclaim is memcg softlimit hint aware, now. But, the memory cgroup's "limit" path can call softlimit shrinker. try_to_free_mem_cgroup_pages() do_try_to_free_pages() shrink_zones() mem_cgroup_soft_limit_reclaim() This will cause a global reclaim when a memcg hits limit. This is bug. soft_limit_reclaim() should be called when scanning_global_lru(sc) == true. And the commit adds a variable "total_scanned" for counting softlimit scanned pages....it's not "total". This patch removes the variable and update sc->nr_scanned instead of it. This will affect shrink_slab()'s scan condition but, global LRU is scanned by softlimit and I think this change makes sense. TODO: avoid too much scanning of a zone when softlimit did enough work. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Ying Han <yinghan@google.com> Cc: Michal Hocko <mhocko@suse.cz> 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.c27
1 files changed, 15 insertions, 12 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 8ff834e19c24..4f49535d4cd3 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1995,14 +1995,13 @@ restart:
1995 * If a zone is deemed to be full of pinned pages then just give it a light 1995 * If a zone is deemed to be full of pinned pages then just give it a light
1996 * scan then give up on it. 1996 * scan then give up on it.
1997 */ 1997 */
1998static unsigned long shrink_zones(int priority, struct zonelist *zonelist, 1998static void shrink_zones(int priority, struct zonelist *zonelist,
1999 struct scan_control *sc) 1999 struct scan_control *sc)
2000{ 2000{
2001 struct zoneref *z; 2001 struct zoneref *z;
2002 struct zone *zone; 2002 struct zone *zone;
2003 unsigned long nr_soft_reclaimed; 2003 unsigned long nr_soft_reclaimed;
2004 unsigned long nr_soft_scanned; 2004 unsigned long nr_soft_scanned;
2005 unsigned long total_scanned = 0;
2006 2005
2007 for_each_zone_zonelist_nodemask(zone, z, zonelist, 2006 for_each_zone_zonelist_nodemask(zone, z, zonelist,
2008 gfp_zone(sc->gfp_mask), sc->nodemask) { 2007 gfp_zone(sc->gfp_mask), sc->nodemask) {
@@ -2017,19 +2016,23 @@ static unsigned long shrink_zones(int priority, struct zonelist *zonelist,
2017 continue; 2016 continue;
2018 if (zone->all_unreclaimable && priority != DEF_PRIORITY) 2017 if (zone->all_unreclaimable && priority != DEF_PRIORITY)
2019 continue; /* Let kswapd poll it */ 2018 continue; /* Let kswapd poll it */
2019 /*
2020 * This steals pages from memory cgroups over softlimit
2021 * and returns the number of reclaimed pages and
2022 * scanned pages. This works for global memory pressure
2023 * and balancing, not for a memcg's limit.
2024 */
2025 nr_soft_scanned = 0;
2026 nr_soft_reclaimed = mem_cgroup_soft_limit_reclaim(zone,
2027 sc->order, sc->gfp_mask,
2028 &nr_soft_scanned);
2029 sc->nr_reclaimed += nr_soft_reclaimed;
2030 sc->nr_scanned += nr_soft_scanned;
2031 /* need some check for avoid more shrink_zone() */
2020 } 2032 }
2021 2033
2022 nr_soft_scanned = 0;
2023 nr_soft_reclaimed = mem_cgroup_soft_limit_reclaim(zone,
2024 sc->order, sc->gfp_mask,
2025 &nr_soft_scanned);
2026 sc->nr_reclaimed += nr_soft_reclaimed;
2027 total_scanned += nr_soft_scanned;
2028
2029 shrink_zone(priority, zone, sc); 2034 shrink_zone(priority, zone, sc);
2030 } 2035 }
2031
2032 return total_scanned;
2033} 2036}
2034 2037
2035static bool zone_reclaimable(struct zone *zone) 2038static bool zone_reclaimable(struct zone *zone)
@@ -2094,7 +2097,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
2094 sc->nr_scanned = 0; 2097 sc->nr_scanned = 0;
2095 if (!priority) 2098 if (!priority)
2096 disable_swap_token(sc->mem_cgroup); 2099 disable_swap_token(sc->mem_cgroup);
2097 total_scanned += shrink_zones(priority, zonelist, sc); 2100 shrink_zones(priority, zonelist, sc);
2098 /* 2101 /*
2099 * Don't shrink slabs when reclaiming memory from 2102 * Don't shrink slabs when reclaiming memory from
2100 * over limit cgroups 2103 * over limit cgroups