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 21/22] mm, compaction: Be selective about what pageblocks to clear skip hints
Date: Thu, 31 Jan 2019 16:45:16 +0100 [thread overview]
Message-ID: <9318efb7-cf20-b87d-9038-27406925b161@suse.cz> (raw)
In-Reply-To: <20190118175136.31341-22-mgorman@techsingularity.net>
On 1/18/19 6:51 PM, Mel Gorman wrote:
> Pageblock hints are cleared when compaction restarts or kswapd makes enough
> progress that it can sleep but it's over-eager in that the bit is cleared
> for migration sources with no LRU pages and migration targets with no free
> pages. As pageblock skip hint flushes are relatively rare and out-of-band
> with respect to kswapd, this patch makes a few more expensive checks to
> see if it's appropriate to even clear the bit. Every pageblock that is
> not cleared will avoid 512 pages being scanned unnecessarily on x86-64.
>
> The impact is variable with different workloads showing small differences
> in latency, success rates and scan rates. This is expected as clearing
> the hints is not that common but doing a small amount of work out-of-band
> to avoid a large amount of work in-band later is generally a good thing.
>
> Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
next prev parent reply other threads:[~2019-01-31 15:45 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
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 [this message]
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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