Re: [patch] mm, oom: do not schedule if current has been killed

[Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

(2012/06/19 10:08), David Rientjes wrote:
> The oom killer currently schedules away from current in an
> uninterruptible sleep if it does not have access to memory reserves.
> It's possible that current was killed because it shares memory with the
> oom killed thread or because it was killed by the user in the interim,
> however.
>
> This patch only schedules away from current if it does not have a pending
> kill, i.e. if it does not share memory with the oom killed thread.  It's
> possible that it will immediately retry its memory allocation and fail,
> but it will immediately be given access to memory reserves if it calls
> the oom killer again.
>
> This prevents the delay of memory freeing when threads that share memory
> with the oom killed thread get unnecessarily scheduled.
>
> Signed-off-by: David Rientjes<rientjes@google.com>

fatal_signal_pending() == false if test_thread_flag(TIF_MEMDIE)==false ?

I'll check memcg code..

Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>



> ---
>   mm/oom_kill.c |    4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -749,7 +749,7 @@ out:
>   	 * Give "p" a good chance of killing itself before we
>   	 * retry to allocate memory unless "p" is current
>   	 */
> -	if (killed&&  !test_thread_flag(TIF_MEMDIE))
> +	if (killed&&  !fatal_signal_pending(current))
>   		schedule_timeout_uninterruptible(1);
>   }
>
> @@ -765,6 +765,6 @@ void pagefault_out_of_memory(void)
>   		out_of_memory(NULL, 0, 0, NULL, false);
>   		clear_system_oom();
>   	}
> -	if (!test_thread_flag(TIF_MEMDIE))
> +	if (!fatal_signal_pending(current))
>   		schedule_timeout_uninterruptible(1);
>   }


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