Commit 39af1765 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds

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: default avatarOleg Nesterov <oleg@redhat.com>
Reviewed-by: default avatarMichal 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f87fb599
...@@ -397,9 +397,15 @@ void mm_update_next_owner(struct mm_struct *mm) ...@@ -397,9 +397,15 @@ void mm_update_next_owner(struct mm_struct *mm)
/* /*
* Search through everything else, we should not get here often. * Search through everything else, we should not get here often.
*/ */
for_each_process_thread(g, c) { for_each_process(g) {
if (!(c->flags & PF_KTHREAD) && c->mm == mm) if (g->flags & PF_KTHREAD)
continue;
for_each_thread(g, c) {
if (c->mm == mm)
goto assign_new_owner; goto assign_new_owner;
if (c->mm)
break;
}
} }
read_unlock(&tasklist_lock); read_unlock(&tasklist_lock);
/* /*
......
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