From: Mel Gorman <mgorman@techsingularity.net>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: Re: [PATCH 2/3] mm, compaction: split off flag for not updating skip hints
Date: Thu, 2 Nov 2017 13:09:43 +0000 [thread overview]
Message-ID: <20171102130943.7dpbuecrywtloein@techsingularity.net> (raw)
In-Reply-To: <20171102121706.21504-2-vbabka@suse.cz>
On Thu, Nov 02, 2017 at 01:17:05PM +0100, Vlastimil Babka wrote:
> Pageblock skip hints were added as a heuristic for compaction, which shares
> core code with CMA. Since CMA reliability would suffer from the heuristics,
> compact_control flag ignore_skip_hint was added for the CMA use case.
> Since commit 6815bf3f233e ("mm/compaction: respect ignore_skip_hint in
> update_pageblock_skip") the flag also means that CMA won't *update* the skip
> hints in addition to ignoring them.
>
> Today, direct compaction can also ignore the skip hints in the last resort
> attempt, but there's no reason not to set them when isolation fails in such
> case. Thus, this patch splits off a new no_set_skip_hint flag to avoid the
> updating, which only CMA sets. This should improve the heuristics a bit, and
> allow us to simplify the persistent skip bit handling as the next step.
>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
--
Mel Gorman
SUSE Labs
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next prev parent reply other threads:[~2017-11-02 13:09 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-02 12:17 [PATCH 1/3] mm, compaction: extend pageblock_skip_persistent() to all compound pages Vlastimil Babka
2017-11-02 12:17 ` [PATCH 2/3] mm, compaction: split off flag for not updating skip hints Vlastimil Babka
2017-11-02 13:09 ` Mel Gorman [this message]
2017-11-02 12:17 ` [PATCH 3/3] mm, compaction: remove unneeded pageblock_skip_persistent() checks Vlastimil Babka
2017-11-02 13:04 ` [PATCH 1/3] mm, compaction: extend pageblock_skip_persistent() to all compound pages Mel Gorman
2017-11-03 20:37 ` David Rientjes
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