From: Michal Hocko <mhocko@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Mel Gorman <mgorman@suse.de>,
David Rientjes <rientjes@google.com>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
Joonsoo Kim <js1304@gmail.com>,
Hillf Danton <hillf.zj@alibaba-inc.com>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
Andrea Arcangeli <aarcange@redhat.com>
Subject: Re: [PATCH 09/14] mm: use compaction feedback for thp backoff conditions
Date: Fri, 29 Apr 2016 11:28:35 +0200 [thread overview]
Message-ID: <20160429092835.GD21977@dhcp22.suse.cz> (raw)
In-Reply-To: <5723267C.1050903@suse.cz>
On Fri 29-04-16 11:16:44, Vlastimil Babka wrote:
> On 04/28/2016 02:35 PM, Michal Hocko wrote:
[...]
> >My main point was to simplify the code and get rid of as much compaction
> >specific hacks as possible. We might very well drop this later on but it
> >would be at least less code to grasp through. I do not have any problem
> >with dropping this but I think this shouldn't collide with other patches
> >much so reducing the number of lines is worth it.
Good point, I have completely missed this part.
> I just realized it also affects khugepaged, and not just THP page faults, so
> it may potentially cripple THP's completely. My main issue is that the
> reasons to bail out includes COMPACT_SKIPPED, and for a wrong reason (see
> the comment above). It also goes against the comment below the noretry
> label:
>
> * High-order allocations do not necessarily loop after direct reclaim
> * and reclaim/compaction depends on compaction being called after
> * reclaim so call directly if necessary.
>
> Given that THP's are large, I expect reclaim would indeed be quite often
> necessary before compaction, and the first optimistic async compaction
> attempt will just return SKIPPED. After this patch, there will be no more
> reclaim/compaction attempts for THP's, including khugepaged. And given the
> change of THP page fault defaults, even crippling that path should no longer
> be necessary.
>
> So I would just drop this for now indeed.
Agreed, thanks for catching this. Andrew, could you drop this patch
please? It was supposed to be a mere clean up without any effect on the
oom detection.
Thanks!
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2016-04-29 9:28 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-20 19:47 [PATCH 0.14] oom detection rework v6 Michal Hocko
2016-04-20 19:47 ` [PATCH 01/14] vmscan: consider classzone_idx in compaction_ready Michal Hocko
2016-04-21 3:32 ` Hillf Danton
2016-05-04 13:56 ` Michal Hocko
2016-04-20 19:47 ` [PATCH 02/14] mm, compaction: change COMPACT_ constants into enum Michal Hocko
2016-04-20 19:47 ` [PATCH 03/14] mm, compaction: cover all compaction mode in compact_zone Michal Hocko
2016-04-20 19:47 ` [PATCH 04/14] mm, compaction: distinguish COMPACT_DEFERRED from COMPACT_SKIPPED Michal Hocko
2016-04-21 7:08 ` Hillf Danton
2016-04-20 19:47 ` [PATCH 05/14] mm, compaction: distinguish between full and partial COMPACT_COMPLETE Michal Hocko
2016-04-21 6:39 ` Hillf Danton
2016-04-20 19:47 ` [PATCH 06/14] mm, compaction: Update compaction_result ordering Michal Hocko
2016-04-21 6:45 ` Hillf Danton
2016-04-20 19:47 ` [PATCH 07/14] mm, compaction: Simplify __alloc_pages_direct_compact feedback interface Michal Hocko
2016-04-21 6:50 ` Hillf Danton
2016-04-20 19:47 ` [PATCH 08/14] mm, compaction: Abstract compaction feedback to helpers Michal Hocko
2016-04-21 6:57 ` Hillf Danton
2016-04-28 8:47 ` Vlastimil Babka
2016-04-20 19:47 ` [PATCH 09/14] mm: use compaction feedback for thp backoff conditions Michal Hocko
2016-04-21 7:05 ` Hillf Danton
2016-04-28 8:53 ` Vlastimil Babka
2016-04-28 12:35 ` Michal Hocko
2016-04-29 9:16 ` Vlastimil Babka
2016-04-29 9:28 ` Michal Hocko [this message]
2016-04-20 19:47 ` [PATCH 10/14] mm, oom: rework oom detection Michal Hocko
2016-04-20 19:47 ` [PATCH 11/14] mm: throttle on IO only when there are too many dirty and writeback pages Michal Hocko
2016-04-20 19:47 ` [PATCH 12/14] mm, oom: protect !costly allocations some more Michal Hocko
2016-04-21 8:03 ` Hillf Danton
2016-05-04 6:01 ` Joonsoo Kim
2016-05-04 6:31 ` Joonsoo Kim
2016-05-04 8:56 ` Michal Hocko
2016-05-04 14:57 ` Joonsoo Kim
2016-05-04 18:19 ` Michal Hocko
2016-05-04 8:53 ` Michal Hocko
2016-05-04 14:39 ` Joonsoo Kim
2016-05-04 18:20 ` Michal Hocko
2016-04-20 19:47 ` [PATCH 13/14] mm: consider compaction feedback also for costly allocation Michal Hocko
2016-04-21 8:13 ` Hillf Danton
2016-04-20 19:47 ` [PATCH 14/14] mm, oom, compaction: prevent from should_compact_retry looping for ever for costly orders Michal Hocko
2016-04-21 8:24 ` Hillf Danton
2016-04-28 8:59 ` Vlastimil Babka
2016-04-28 12:39 ` Michal Hocko
2016-05-04 6:27 ` Joonsoo Kim
2016-05-04 9:04 ` Michal Hocko
2016-05-04 15:14 ` Joonsoo Kim
2016-05-04 19:22 ` Michal Hocko
2016-05-04 5:45 ` [PATCH 0.14] oom detection rework v6 Joonsoo Kim
2016-05-04 8:12 ` Vlastimil Babka
2016-05-04 8:32 ` Joonsoo Kim
2016-05-04 8:50 ` Michal Hocko
2016-05-04 8:47 ` Michal Hocko
2016-05-04 14:32 ` Joonsoo Kim
2016-05-04 18:16 ` Michal Hocko
2016-05-10 6:41 ` Joonsoo Kim
2016-05-10 7:09 ` Vlastimil Babka
2016-05-10 8:00 ` Joonsoo Kim
2016-05-10 9:44 ` Michal Hocko
2016-05-10 9:43 ` Michal Hocko
2016-05-12 2:23 ` Joonsoo Kim
2016-05-12 5:19 ` Joonsoo Kim
2016-05-12 10:59 ` Michal Hocko
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