From: Xishi Qiu <qiuxishi@huawei.com>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: linux-mm@kvack.org, Johannes Weiner <hannes@cmpxchg.org>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
David Rientjes <rientjes@google.com>,
Mel Gorman <mgorman@techsingularity.net>,
linux-kernel@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH v2 04/10] mm, page_alloc: count movable pages when stealing from pageblock
Date: Tue, 14 Feb 2017 18:07:53 +0800 [thread overview]
Message-ID: <58A2D6F9.6030400@huawei.com> (raw)
In-Reply-To: <20170210172343.30283-5-vbabka@suse.cz>
On 2017/2/11 1:23, Vlastimil Babka wrote:
> When stealing pages from pageblock of a different migratetype, we count how
> many free pages were stolen, and change the pageblock's migratetype if more
> than half of the pageblock was free. This might be too conservative, as there
> might be other pages that are not free, but were allocated with the same
> migratetype as our allocation requested.
>
> While we cannot determine the migratetype of allocated pages precisely (at
> least without the page_owner functionality enabled), we can count pages that
> compaction would try to isolate for migration - those are either on LRU or
> __PageMovable(). The rest can be assumed to be MIGRATE_RECLAIMABLE or
> MIGRATE_UNMOVABLE, which we cannot easily distinguish. This counting can be
> done as part of free page stealing with little additional overhead.
>
> The page stealing code is changed so that it considers free pages plus pages
> of the "good" migratetype for the decision whether to change pageblock's
> migratetype.
>
> The result should be more accurate migratetype of pageblocks wrt the actual
> pages in the pageblocks, when stealing from semi-occupied pageblocks. This
> should help the efficiency of page grouping by mobility.
>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Hi Vlastimil,
How about these two changes?
1. If we steal some free pages, we will add these page at the head of start_migratetype
list, it will cause more fixed, because these pages will be allocated more easily.
So how about use list_move_tail instead of list_move?
__rmqueue_fallback
steal_suitable_fallback
move_freepages_block
move_freepages
list_move
2. When doing expand() - list_add(), usually the list is empty, but in the
following case, the list is not empty, because we did move_freepages_block()
before.
__rmqueue_fallback
steal_suitable_fallback
move_freepages_block // move to the list of start_migratetype
expand // split the largest order
list_add // add to the list of start_migratetype
So how about use list_add_tail instead of list_add? Then we can merge the large
block again as soon as the page freed.
Thanks,
Xishi Qiu
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next prev parent reply other threads:[~2017-02-14 10:12 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-10 17:23 [PATCH v2 00/10] try to reduce fragmenting fallbacks Vlastimil Babka
2017-02-10 17:23 ` [PATCH v2 01/10] mm, compaction: reorder fields in struct compact_control Vlastimil Babka
2017-02-13 10:49 ` Mel Gorman
2017-02-14 16:33 ` Johannes Weiner
2017-02-10 17:23 ` [PATCH v2 02/10] mm, compaction: remove redundant watermark check in compact_finished() Vlastimil Babka
2017-02-13 10:49 ` Mel Gorman
2017-02-14 16:34 ` Johannes Weiner
2017-02-10 17:23 ` [PATCH v2 03/10] mm, page_alloc: split smallest stolen page in fallback Vlastimil Babka
2017-02-13 10:51 ` Mel Gorman
2017-02-13 10:54 ` Vlastimil Babka
2017-02-14 16:59 ` Johannes Weiner
2017-02-10 17:23 ` [PATCH v2 04/10] mm, page_alloc: count movable pages when stealing from pageblock Vlastimil Babka
2017-02-13 10:53 ` Mel Gorman
2017-02-14 10:07 ` Xishi Qiu [this message]
2017-02-15 10:47 ` Vlastimil Babka
2017-02-15 11:56 ` Xishi Qiu
2017-02-17 16:21 ` Vlastimil Babka
2017-02-14 18:10 ` Johannes Weiner
2017-02-17 16:09 ` Vlastimil Babka
2017-02-10 17:23 ` [PATCH v2 05/10] mm, compaction: change migrate_async_suitable() to suitable_migration_source() Vlastimil Babka
2017-02-13 10:53 ` Mel Gorman
2017-02-14 18:12 ` Johannes Weiner
2017-02-10 17:23 ` [PATCH v2 06/10] mm, compaction: add migratetype to compact_control Vlastimil Babka
2017-02-13 10:53 ` Mel Gorman
2017-02-14 18:15 ` Johannes Weiner
2017-02-10 17:23 ` [PATCH v2 07/10] mm, compaction: restrict async compaction to pageblocks of same migratetype Vlastimil Babka
2017-02-13 10:56 ` Mel Gorman
2017-02-14 20:10 ` Johannes Weiner
2017-02-17 16:32 ` Vlastimil Babka
2017-02-17 17:39 ` Johannes Weiner
2017-02-10 17:23 ` [PATCH v2 08/10] mm, compaction: finish whole pageblock to reduce fragmentation Vlastimil Babka
2017-02-13 10:57 ` Mel Gorman
2017-02-16 11:44 ` Johannes Weiner
2017-02-10 17:23 ` [RFC v2 09/10] mm, page_alloc: disallow migratetype fallback in fastpath Vlastimil Babka
2017-02-10 17:23 ` [RFC v2 10/10] mm, page_alloc: introduce MIGRATE_MIXED migratetype Vlastimil Babka
2017-03-08 2:16 ` Yisheng Xie
2017-03-08 7:07 ` Vlastimil Babka
2017-03-13 2:16 ` Yisheng Xie
2017-02-13 11:07 ` [PATCH v2 00/10] try to reduce fragmenting fallbacks Mel Gorman
2017-02-15 14:29 ` Vlastimil Babka
2017-02-15 16:11 ` Vlastimil Babka
2017-02-15 20:11 ` Vlastimil Babka
2017-02-16 15:12 ` Vlastimil Babka
2017-02-17 15:24 ` Vlastimil Babka
2017-02-20 12:30 ` Vlastimil Babka
2017-02-23 16:01 ` Mel Gorman
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