On Fri 03-02-17 19:57:39, Tetsuo Handa wrote: > Michal Hocko wrote: > > On Mon 30-01-17 09:55:46, Michal Hocko wrote: > > > On Sun 29-01-17 00:27:27, Tetsuo Handa wrote: > > [...] > > > > Regarding [1], it helped avoiding the too_many_isolated() issue. I can't > > > > tell whether it has any negative effect, but I got on the first trial > > > > that > > > > all allocating threads are blocked on wait_for_completion() from > > > > flush_work() > > > > in drain_all_pages() introduced by "mm, page_alloc: drain per-cpu pages > > > > from > > > > workqueue context". There was no warn_alloc() stall warning message > > > > afterwords. > > > > > > That patch is buggy and there is a follow up [1] which is not sitting in > > > the > > > mmotm (and thus linux-next) yet. I didn't get to review it properly and > > > I cannot say I would be too happy about using WQ from the page > > > allocator. I believe even the follow up needs to have WQ_RECLAIM WQ. > > > > > > [1] > > > http://lkml.kernel.org/r/[email protected] > > > > Did you get chance to test with this follow up patch? It would be > > interesting to see whether OOM situation can still starve the waiter. > > The current linux-next should contain this patch. > > So far I can't reproduce problems except two listed below (cond_resched() trap > in printk() and IDLE priority trap are excluded from the list).
OK, so it seems that all the distractions are handled now and linux-next should provide a reasonable base for testing. You said you weren't able to reproduce the original long stalls on too_many_isolated(). I would be still interested to see those oom reports and potential anomalies in the isolated counts before I send the patch for inclusion so your further testing would be more than appreciated. Also stalls > 10s without any previous occurrences would be interesting. Thanks! -- Michal Hocko SUSE Labs
