On 2017/12/07 17:34, Michal Hocko wrote: > 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. > I wish that normal threads do not invoke direct reclaim operation. Only dedicated kernel threads (such as filesystem's writeback) invoke direct reclaim operation. Then, we can implement __GFP_KILLABLE for normal threads, and hopefully get rid of distinction between GFP_NOIO/ GFP_NOFS/GFP_KERNEL because reclaim (and locking) dependency becomes simpler. -- 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>
