From: Michal Hocko <mhocko@xxxxxxxx> oom_kill_process makes sure to kill all processes outside of the thread group which are sharing the mm. This requires to iterate over all tasks. This is however not a common case so we can optimize it a bit and only do that path only if we know that there are external users of the mm struct outside of the thread group. Signed-off-by: Michal Hocko <mhocko@xxxxxxxx> --- mm/oom_kill.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 5bb2f7698ad7..0e33e912f7e4 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -820,6 +820,13 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p, task_unlock(victim); /* + * skip expensive iterations over all tasks if we know that there + * are no users outside of threads in the same thread group + */ + if (atomic_read(&mm->mm_users) <= get_nr_threads(victim)) + goto oom_reap; + + /* * Kill all user processes sharing victim->mm in other thread groups, if * any. They don't get access to memory reserves, though, to avoid * depletion of all memory. This prevents mm->mmap_sem livelock when an @@ -848,6 +855,7 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p, } rcu_read_unlock(); +oom_reap: if (can_oom_reap) wake_oom_reaper(victim); -- 2.8.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>