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From: Mel Gorman <mgorman@techsingularity.net>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
	Linux-MM <linux-mm@kvack.org>,
	Mel Gorman <mgorman@techsingularity.net>
Subject: [PATCH 06/22] mm, migrate: Immediately fail migration of a page with no migration handler
Date: Fri, 18 Jan 2019 17:51:20 +0000	[thread overview]
Message-ID: <20190118175136.31341-7-mgorman@techsingularity.net> (raw)
In-Reply-To: <20190118175136.31341-1-mgorman@techsingularity.net>

Pages with no migration handler use a fallback handler which sometimes
works and sometimes persistently retries. A historical example was blockdev
pages but there are others such as odd refcounting when page->private
is used.  These are retried multiple times which is wasteful during
compaction so this patch will fail migration faster unless the caller
specifies MIGRATE_SYNC.

This is not expected to help THP allocation success rates but it did
reduce latencies very slightly in some cases.

1-socket thpfioscale
                                        4.20.0                 4.20.0
                              noreserved-v2r15         failfast-v2r15
Amean     fault-both-1         0.00 (   0.00%)        0.00 *   0.00%*
Amean     fault-both-3      3839.67 (   0.00%)     3833.72 (   0.15%)
Amean     fault-both-5      5177.47 (   0.00%)     4967.15 (   4.06%)
Amean     fault-both-7      7245.03 (   0.00%)     7139.19 (   1.46%)
Amean     fault-both-12    11534.89 (   0.00%)    11326.30 (   1.81%)
Amean     fault-both-18    16241.10 (   0.00%)    16270.70 (  -0.18%)
Amean     fault-both-24    19075.91 (   0.00%)    19839.65 (  -4.00%)
Amean     fault-both-30    22712.11 (   0.00%)    21707.05 (   4.43%)
Amean     fault-both-32    21692.92 (   0.00%)    21968.16 (  -1.27%)

The 2-socket results are not materially different. Scan rates are similar
as expected.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/migrate.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/migrate.c b/mm/migrate.c
index 52b04c217e30..4512afab46ac 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -916,7 +916,7 @@ static int fallback_migrate_page(struct address_space *mapping,
 	 */
 	if (page_has_private(page) &&
 	    !try_to_release_page(page, GFP_KERNEL))
-		return -EAGAIN;
+		return mode == MIGRATE_SYNC ? -EAGAIN : -EBUSY;
 
 	return migrate_page(mapping, newpage, page, mode);
 }
-- 
2.16.4


  parent reply	other threads:[~2019-01-18 17:52 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 ` Mel Gorman [this message]
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
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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