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authorMichal Hocko <mhocko@suse.cz>2013-09-12 15:13:30 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-12 15:38:01 -0700
commite839b6a1c8d0895803bcbd587595a54f4221a625 (patch)
tree0ec95c564cb6f4c0ca0858dd88a3364ee0e383e5
parent7d910c054be42515cd3e43f2e1bec8c536632de2 (diff)
memcg, vmscan: do not attempt soft limit reclaim if it would not scan anything
mem_cgroup_should_soft_reclaim controls whether soft reclaim pass is done and it always says yes currently. Memcg iterators are clever to skip nodes that are not soft reclaimable quite efficiently but mem_cgroup_should_soft_reclaim can be more clever and do not start the soft reclaim pass at all if it knows that nothing would be scanned anyway. In order to do that, simply reuse mem_cgroup_soft_reclaim_eligible for the target group of the reclaim and allow the pass only if the whole subtree wouldn't be skipped. Signed-off-by: Michal Hocko <mhocko@suse.cz> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Glauber Costa <glommer@openvz.org> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Michel Lespinasse <walken@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/memcontrol.c6
-rw-r--r--mm/vmscan.c4
2 files changed, 8 insertions, 2 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index a18e228f140b..848fc6c195d2 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1885,7 +1885,11 @@ enum mem_cgroup_filter_t
mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg,
struct mem_cgroup *root)
{
- struct mem_cgroup *parent = memcg;
+ struct mem_cgroup *parent;
+
+ if (!memcg)
+ memcg = root_mem_cgroup;
+ parent = memcg;
if (res_counter_soft_limit_excess(&memcg->res))
return VISIT;
diff --git a/mm/vmscan.c b/mm/vmscan.c
index f2e35099508b..04dca89c4f34 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -142,7 +142,9 @@ static bool global_reclaim(struct scan_control *sc)
static bool mem_cgroup_should_soft_reclaim(struct scan_control *sc)
{
- return !mem_cgroup_disabled();
+ struct mem_cgroup *root = sc->target_mem_cgroup;
+ return !mem_cgroup_disabled() &&
+ mem_cgroup_soft_reclaim_eligible(root, root) != SKIP_TREE;
}
#else
static bool global_reclaim(struct scan_control *sc)