On 2017/12/09 6:02, David Rientjes wrote: > On Thu, 7 Dec 2017, 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. >> > > I've proposed a similar patch in the past, but for a check on TIF_MEMDIE, > which would today be a tsk_is_oom_victim(current), since we had observed > lengthy stalls in reclaim that would have been prevented if the oom victim > had exited out, returned back to the page allocator, allocated with > ALLOC_NO_WATERMARKS, and proceeded to quickly exit. > > I'm not sure that all fatal_signal_pending() tasks should get the same > treatment, but I understand the point that the task is killed and should > free memory when it fully exits. How much memory is unknown. > We can use __GFP_KILLABLE. Unless there is performance impact for checking fatal_siganl_pending(), allowing only fatal_signal_pending() threads with __GFP_KILLABLE to bail out (without using memory reserves) should be safe. -- 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>
