On Thu 28-01-16 16:12:40, Johannes Weiner wrote: > On Thu, Jan 28, 2016 at 09:11:23PM +0100, Michal Hocko wrote: > > On Thu 28-01-16 20:02:04, Andrea Arcangeli wrote: > > > It's not immediately apparent if there is a new OOM killer upstream > > > logic that would prevent the risk of a second OOM killer invocation > > > despite another OOM killing already happened while we were stuck in > > > reclaim. In absence of that, the high wmark check would be still > > > needed. > > > > Well, my oom detection rework [1] strives to make the OOM detection more > > robust and the retry logic performs the watermark check. So I think the > > last attempt is no longer needed after that patch. I will then remove > > it. > > Hm? I don't have the same conclusion from what Andrea said. > > When you have many allocations racing at the same time, they can all > enter __alloc_pages_may_oom() in quick succession. We don't want a > cavalcade of OOM kills when one could be enough, so we have to make > sure that in between should_alloc_retry() giving up and acquiring the > OOM lock nobody else already issued a kill and released enough memory. > > It's a race window that gets yanked wide open when hundreds of threads > race in __alloc_pages_may_oom(). Your patches don't fix that, AFAICS. Only one task would be allowed to go out_of_memory and all the rest will simply fail on oom_lock trylock and return with NULL. Or am I missing your point? -- 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>