From: Vlastimil Babka <vbabka@suse.cz>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Arkadiusz Miskiewicz <a.miskiewicz@gmail.com>,
Ralf-Peter Rohbeck <Ralf-Peter.Rohbeck@quantum.com>,
Olaf Hering <olaf@aepfle.de>, Michal Hocko <mhocko@kernel.org>,
Mel Gorman <mgorman@techsingularity.net>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
David Rientjes <rientjes@google.com>,
Rik van Riel <riel@redhat.com>,
Hillf Danton <hillf.zj@alibaba-inc.com>,
Michal Hocko <mhocko@suse.com>
Subject: Re: [PATCH 3/4] mm, compaction: ignore fragindex from compaction_zonelist_suitable()
Date: Thu, 29 Sep 2016 11:57:01 +0200 [thread overview]
Message-ID: <cadadd38-6456-f58e-504f-cc18ddc47b3f@suse.cz> (raw)
In-Reply-To: <20160926162025.21555-4-vbabka@suse.cz>
On 09/26/2016 06:20 PM, Vlastimil Babka wrote:
> The compaction_zonelist_suitable() function tries to determine if compaction
> will be able to proceed after sufficient reclaim, i.e. whether there are
> enough reclaimable pages to provide enough order-0 freepages for compaction.
>
> This addition of reclaimable pages to the free pages works well for the order-0
> watermark check, but in the fragmentation index check we only consider truly
> free pages. Thus we can get fragindex value close to 0 which indicates failure
> do to lack of memory, and wrongly decide that compaction won't be suitable even
> after reclaim.
>
> Instead of trying to somehow adjust fragindex for reclaimable pages, let's just
> skip it from compaction_zonelist_suitable().
>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Mel Gorman <mgorman@techsingularity.net>
> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Cc: David Rientjes <rientjes@google.com>
> Cc: Rik van Riel <riel@redhat.com>
Bah, a fix below, sorry.
----8<----
next prev parent reply other threads:[~2016-09-29 9:57 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-26 16:20 [PATCH 0/4] followups to reintroduce compaction feedback for OOM decisions Vlastimil Babka
2016-09-26 16:20 ` [PATCH 1/4] mm, compaction: more reliably increase direct compaction priority-fix Vlastimil Babka
2016-09-27 3:25 ` Hillf Danton
2016-09-26 16:20 ` [PATCH 2/4] mm, page_alloc: pull no_progress_loops update to should_reclaim_retry() Vlastimil Babka
2016-09-26 16:20 ` [PATCH 3/4] mm, compaction: ignore fragindex from compaction_zonelist_suitable() Vlastimil Babka
2016-09-26 20:15 ` Michal Hocko
2016-09-29 9:57 ` Vlastimil Babka [this message]
2016-09-26 16:20 ` [PATCH 4/4] mm, compaction: restrict fragindex to costly orders Vlastimil Babka
2016-09-26 20:29 ` Michal Hocko
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