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From: Vlastimil Babka <vbabka@suse.cz>
To: Mel Gorman <mgorman@techsingularity.net>,
	Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
	Linux-MM <linux-mm@kvack.org>
Subject: Re: [PATCH 20/22] mm, compaction: Sample pageblocks for free pages
Date: Thu, 31 Jan 2019 16:39:19 +0100	[thread overview]
Message-ID: <919af440-28d2-465b-3414-bb4719b844ae@suse.cz> (raw)
In-Reply-To: <20190118175136.31341-21-mgorman@techsingularity.net>

On 1/18/19 6:51 PM, Mel Gorman wrote:
> Once fast searching finishes, there is a possibility that the linear
> scanner is scanning full blocks found by the fast scanner earlier. This
> patch uses an adaptive stride to sample pageblocks for free pages. The
> more consecutive full pageblocks encountered, the larger the stride until
> a pageblock with free pages is found. The scanners might meet slightly
> sooner but it is an acceptable risk given that the search of the free
> lists may still encounter the pages and adjust the cached PFN of the free
> scanner accordingly.
> 
>                                      5.0.0-rc1              5.0.0-rc1
>                               roundrobin-v3r17       samplefree-v3r17
> Amean     fault-both-1         0.00 (   0.00%)        0.00 *   0.00%*
> Amean     fault-both-3      2752.37 (   0.00%)     2729.95 (   0.81%)
> Amean     fault-both-5      4341.69 (   0.00%)     4397.80 (  -1.29%)
> Amean     fault-both-7      6308.75 (   0.00%)     6097.61 (   3.35%)
> Amean     fault-both-12    10241.81 (   0.00%)     9407.15 (   8.15%)
> Amean     fault-both-18    13736.09 (   0.00%)    10857.63 *  20.96%*
> Amean     fault-both-24    16853.95 (   0.00%)    13323.24 *  20.95%*
> Amean     fault-both-30    15862.61 (   0.00%)    17345.44 (  -9.35%)
> Amean     fault-both-32    18450.85 (   0.00%)    16892.00 (   8.45%)
> 
> The latency is mildly improved offseting some overhead from earlier
> patches that are prerequisites for the rest of the series.  However,
> a major impact is on the free scan rate with an 82% reduction.
> 
>                                 5.0.0-rc1      5.0.0-rc1
>                          roundrobin-v3r17 samplefree-v3r17
> Compaction migrate scanned    21607271            20116887
> Compaction free scanned       95336406            16668703
> 
> It's also the first time in the series where the number of pages scanned
> by the migration scanner is greater than the free scanner due to the
> increased search efficiency.
> 
> Signed-off-by: Mel Gorman <mgorman@techsingularity.net>

Acked-by: Vlastimil Babka <vbabka@suse.cz>

  reply	other threads:[~2019-01-31 15:39 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-18 17:51 [PATCH 00/22] Increase success rates and reduce latency of compaction v3 Mel Gorman
2019-01-18 17:51 ` [PATCH 01/22] mm, compaction: Shrink compact_control Mel Gorman
2019-01-18 17:51 ` [PATCH 02/22] mm, compaction: Rearrange compact_control Mel Gorman
2019-01-18 17:51 ` [PATCH 03/22] mm, compaction: Remove last_migrated_pfn from compact_control Mel Gorman
2019-01-18 17:51 ` [PATCH 04/22] mm, compaction: Remove unnecessary zone parameter in some instances Mel Gorman
2019-01-18 17:51 ` [PATCH 05/22] mm, compaction: Rename map_pages to split_map_pages Mel Gorman
2019-01-18 17:51 ` [PATCH 06/22] mm, migrate: Immediately fail migration of a page with no migration handler Mel Gorman
2019-01-18 17:51 ` [PATCH 07/22] mm, compaction: Always finish scanning of a full pageblock Mel Gorman
2019-01-18 17:51 ` [PATCH 08/22] mm, compaction: Ignore the fragmentation avoidance boost for isolation and compaction Mel Gorman
2019-01-18 17:51 ` [PATCH 09/22] mm, compaction: Use free lists to quickly locate a migration source Mel Gorman
2019-01-31 13:55   ` Vlastimil Babka
2019-01-31 14:12     ` Vlastimil Babka
2019-02-01 15:06     ` Mel Gorman
2019-02-04  8:55       ` [PATCH] mm, compaction: Use free lists to quickly locate a migration source -fix Mel Gorman
2019-02-08 17:10   ` [PATCH 09/22] mm, compaction: Use free lists to quickly locate a migration source Vlastimil Babka
2019-01-18 17:51 ` [PATCH 10/22] mm, compaction: Keep migration source private to a single compaction instance Mel Gorman
2019-01-18 17:51 ` [PATCH 11/22] mm, compaction: Use free lists to quickly locate a migration target Mel Gorman
2019-01-31 14:52   ` Vlastimil Babka
2019-02-01 14:51     ` Mel Gorman
2019-02-01 14:58       ` Vlastimil Babka
2019-02-04 12:01         ` [PATCH] mm, compaction: Use free lists to quickly locate a migration source -fix Mel Gorman
2021-01-12  5:19     ` [PATCH] mm, compaction: make sure we isolate a valid freepage when high_pfn is used Rokudo Yan
2021-01-12  9:10       ` Mel Gorman
2021-01-12  9:47         ` [PATCH] mm, compaction: move high_pfn to the for loop scope Rokudo Yan
2021-01-12 10:45           ` Mel Gorman
2021-01-12 10:48           ` Vlastimil Babka
2021-01-12 22:27           ` Andrew Morton
2021-01-18  7:41             ` Rokudo Yan
2021-01-18  9:42               ` Mel Gorman
2019-01-18 17:51 ` [PATCH 12/22] mm, compaction: Avoid rescanning the same pageblock multiple times Mel Gorman
2019-01-18 17:51 ` [PATCH 13/22] mm, compaction: Finish pageblock scanning on contention Mel Gorman
2019-01-18 17:51 ` [PATCH 14/22] mm, compaction: Check early for huge pages encountered by the migration scanner Mel Gorman
2019-01-18 17:51 ` [PATCH 15/22] mm, compaction: Keep cached migration PFNs synced for unusable pageblocks Mel Gorman
2019-01-18 17:51 ` [PATCH 16/22] mm, compaction: Rework compact_should_abort as compact_check_resched Mel Gorman
2019-01-18 17:51 ` [PATCH 17/22] mm, compaction: Do not consider a need to reschedule as contention Mel Gorman
2019-01-18 17:51 ` [PATCH 18/22] mm, compaction: Reduce premature advancement of the migration target scanner Mel Gorman
2019-01-18 17:51 ` [PATCH 19/22] mm, compaction: Round-robin the order while searching the free lists for a target Mel Gorman
2019-01-18 17:51 ` [PATCH 20/22] mm, compaction: Sample pageblocks for free pages Mel Gorman
2019-01-31 15:39   ` Vlastimil Babka [this message]
2019-01-18 17:51 ` [PATCH 21/22] mm, compaction: Be selective about what pageblocks to clear skip hints Mel Gorman
2019-01-31 15:45   ` Vlastimil Babka
2019-01-18 17:51 ` [PATCH 22/22] mm, compaction: Capture a page under direct compaction Mel Gorman
2019-01-31 16:11   ` Vlastimil Babka
2019-02-01 14:38     ` [PATCH] mm, compaction: Capture a page under direct compaction -fix Mel Gorman
2019-01-24  8:53 ` [PATCH 00/22] Increase success rates and reduce latency of compaction v3 Mel Gorman

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