Re: [PATCH] mm: terminate shrink_slab loop if signal is pending

Sergey Senozhatsky
2017-12-07T09:52:35Z

On (12/06/17 11:20), Suren Baghdasaryan wrote:
> Slab shrinkers can be quite time consuming and when signal
> is pending they can delay handling of the signal. If fatal
> signal is pending there is no point in shrinking that process
> since it will be killed anyway. This change checks for pending
> fatal signals inside shrink_slab loop and if one is detected
> terminates this loop early.
>
> Signed-off-by: Suren Baghdasaryan <surenb@google.com>
> ---
> mm/vmscan.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index c02c850ea349..69296528ff33 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -486,6 +486,13 @@ static unsigned long shrink_slab(gfp_t gfp_mask, int nid,
> .memcg = memcg,
> };
>
> + /*
> + * We are about to die and free our memory.
> + * Stop shrinking which might delay signal handling.
> + */
> + if (unlikely(fatal_signal_pending(current))

- if (unlikely(fatal_signal_pending(current))
+ if (unlikely(fatal_signal_pending(current)))

-ss