From: Vlastimil Babka <vbabka@suse.cz>
To: Michal Hocko <mhocko@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>
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>,
Michal Hocko <mhocko@suse.com>
Subject: Re: [PATCH 08/11] mm, compaction: Simplify __alloc_pages_direct_compact feedback interface
Date: Mon, 11 Apr 2016 15:48:46 +0200 [thread overview]
Message-ID: <570BAB3E.1060601@suse.cz> (raw)
In-Reply-To: <1459855533-4600-9-git-send-email-mhocko@kernel.org>
On 04/05/2016 01:25 PM, Michal Hocko wrote:
> From: Michal Hocko <mhocko@suse.com>
>
> __alloc_pages_direct_compact communicates potential back off by two
> variables:
> - deferred_compaction tells that the compaction returned
> COMPACT_DEFERRED
> - contended_compaction is set when there is a contention on
> zone->lock resp. zone->lru_lock locks
>
> __alloc_pages_slowpath then backs of for THP allocation requests to
> prevent from long stalls. This is rather messy and it would be much
> cleaner to return a single compact result value and hide all the nasty
> details into __alloc_pages_direct_compact.
On the other hand, the nasty subtle details of THP allocation handling
are now split between __alloc_pages_direct_compact and
__alloc_pages_slowpath(). Lesser evil, I guess. I wish we could get rid
of these special cases, now that latency of THP direct allocations is
reduced by Mel's new defaults.
> This patch shouldn't introduce any functional changes.
>
> Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
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next prev parent reply other threads:[~2016-04-11 13:48 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-05 11:25 [PATCH 00/11] oom detection rework v5 Michal Hocko
2016-04-05 11:25 ` [PATCH 01/11] mm, oom: rework oom detection Michal Hocko
2016-04-05 11:25 ` [PATCH 02/11] mm: throttle on IO only when there are too many dirty and writeback pages Michal Hocko
2016-04-05 11:25 ` [PATCH 03/11] mm, compaction: change COMPACT_ constants into enum Michal Hocko
2016-04-05 11:25 ` [PATCH 04/11] mm, compaction: cover all compaction mode in compact_zone Michal Hocko
2016-04-05 11:25 ` [PATCH 05/11] mm, compaction: distinguish COMPACT_DEFERRED from COMPACT_SKIPPED Michal Hocko
2016-04-11 11:02 ` Vlastimil Babka
2016-04-11 11:24 ` Michal Hocko
2016-04-05 11:25 ` [PATCH 06/11] mm, compaction: distinguish between full and partial COMPACT_COMPLETE Michal Hocko
2016-04-11 12:10 ` Vlastimil Babka
2016-04-11 12:46 ` Michal Hocko
2016-04-11 12:53 ` Vlastimil Babka
2016-04-11 13:27 ` Michal Hocko
2016-04-11 13:42 ` Vlastimil Babka
2016-04-11 13:46 ` Michal Hocko
2016-04-05 11:25 ` [PATCH 07/11] mm, compaction: Update compaction_result ordering Michal Hocko
2016-04-11 12:16 ` Vlastimil Babka
2016-04-05 11:25 ` [PATCH 08/11] mm, compaction: Simplify __alloc_pages_direct_compact feedback interface Michal Hocko
2016-04-11 13:48 ` Vlastimil Babka [this message]
2016-04-05 11:25 ` [PATCH 09/11] mm, compaction: Abstract compaction feedback to helpers Michal Hocko
2016-04-05 23:58 ` Andrew Morton
2016-04-06 0:55 ` Hugh Dickins
2016-04-06 9:26 ` Michal Hocko
2016-04-06 17:46 ` Andrew Morton
2016-04-11 14:39 ` Vlastimil Babka
2016-04-11 15:14 ` Michal Hocko
2016-04-11 15:33 ` Michal Hocko
2016-04-12 11:53 ` Vlastimil Babka
2016-04-12 12:23 ` Michal Hocko
2016-04-11 15:40 ` Michal Hocko
2016-04-11 16:07 ` [RFC PATCH] mm: use compaction feedback for thp backoff conditions Michal Hocko
2016-04-12 11:54 ` [PATCH 09/11] mm, compaction: Abstract compaction feedback to helpers Vlastimil Babka
2016-04-05 11:25 ` [PATCH 10/11] mm, oom: protect !costly allocations some more Michal Hocko
2016-04-06 0:06 ` Andrew Morton
2016-04-06 9:28 ` Michal Hocko
2016-04-11 14:48 ` Vlastimil Babka
2016-04-05 11:25 ` [PATCH 11/11] mm: consider compaction feedback also for costly allocation Michal Hocko
2016-04-05 12:46 ` Michal Hocko
2016-04-11 15:07 ` Vlastimil Babka
2016-04-05 12:47 ` [PATCH 00/11] oom detection rework v5 Michal Hocko
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