On Wed 06-12-17 11:20:26, 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. This is not enough. You would have to make sure the direct reclaim will bail out immeditally which is not at all that simple. We do check fatal signals in throttle_direct_reclaim and conditionally in shrink_inactive_list so even if you bail out from shrinkers we could still finish the full reclaim cycle. Besides that shrinkers shouldn't really take very long so this looks like it papers over a real bug somewhere else. I am not saying the patch is wrong but it would deserve much more details to judge wether this is the right way to go for your particular problem. > Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx> > --- > 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)) > + break; > + > /* > * If kernel memory accounting is disabled, we ignore > * SHRINKER_MEMCG_AWARE flag and call all shrinkers > -- > 2.15.1.424.g9478a66081-goog > -- Michal Hocko SUSE Labs -- 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>
