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authorOleg Nesterov <oleg@redhat.com>2014-06-04 16:07:54 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-06-04 16:54:03 -0700
commit39af1765f1255b2bbadc3064e16270781abf24a1 (patch)
tree55d8a858a7ab136314a397bebbd5bd72f0b0ee2b /kernel/exit.c
parentf87fb599ae4d2a152a93f9821b94f3158146d097 (diff)
downloadlinux-sh-39af1765f1255b2bbadc3064e16270781abf24a1.tar.gz
memcg: optimize the "Search everything else" loop in mm_update_next_owner()
for_each_process_thread() is sub-optimal. All threads share the same ->mm, we can swicth to the next process once we found a thread with ->mm != NULL and ->mm != mm. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Peter Chiang <pchiang@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/exit.c')
-rw-r--r--kernel/exit.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index 5ac3c19c245c..750c2e594617 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -397,9 +397,15 @@ retry:
/*
* Search through everything else, we should not get here often.
*/
- for_each_process_thread(g, c) {
- if (!(c->flags & PF_KTHREAD) && c->mm == mm)
- goto assign_new_owner;
+ for_each_process(g) {
+ if (g->flags & PF_KTHREAD)
+ continue;
+ for_each_thread(g, c) {
+ if (c->mm == mm)
+ goto assign_new_owner;
+ if (c->mm)
+ break;
+ }
}
read_unlock(&tasklist_lock);
/*