Re: [patch 01/12] mm: oom_kill: remove unnecessary locking in oom_enable()

Michal Hocko
2015-03-26T11:43:12Z

On Wed 25-03-15 02:17:05, Johannes Weiner wrote:
> Setting oom_killer_disabled to false is atomic, there is no need for
> further synchronization with ongoing allocations trying to OOM-kill.

True, races with an ongoing allocations are not harmful.

> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>

Acked-by: Michal Hocko <mhocko@suse.cz>

> ---
> mm/oom_kill.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> index 2b665da1b3c9..73763e489e86 100644
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -488,9 +488,7 @@ bool oom_killer_disable(void)
> */
> void oom_killer_enable(void)
> {
> - down_write(&oom_sem);
> oom_killer_disabled = false;
> - up_write(&oom_sem);
> }
>
> #define K(x) ((x) << (PAGE_SHIFT-10))
> --
> 2.3.3
>
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--
Michal Hocko
SUSE Labs