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From: Mel Gorman <mgorman@techsingularity.net>
To: Linux-MM <linux-mm@kvack.org>
Cc: David Rientjes <rientjes@google.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Michal Hocko <mhocko@kernel.org>,
	ying.huang@intel.com, kirill@shutemov.name,
	Andrew Morton <akpm@linux-foundation.org>,
	Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
	Mel Gorman <mgorman@techsingularity.net>
Subject: [PATCH 09/14] mm, compaction: Ignore the fragmentation avoidance boost for isolation and compaction
Date: Fri, 14 Dec 2018 23:03:05 +0000	[thread overview]
Message-ID: <20181214230310.572-10-mgorman@techsingularity.net> (raw)
In-Reply-To: <20181214230310.572-1-mgorman@techsingularity.net>

When pageblocks get fragmented, watermarks are artifically boosted to pages
are reclaimed to avoid further fragmentation events. However, compaction
is often either fragmentation-neutral or moving movable pages away from
unmovable/reclaimable pages. As the actual watermarks are preserved,
allow compaction to ignore the boost factor.

1-socket thpscale
                                    4.20.0-rc6             4.20.0-rc6
                               finishscan-v1r4           noboost-v1r4
Amean     fault-both-1         0.00 (   0.00%)        0.00 *   0.00%*
Amean     fault-both-3      3849.90 (   0.00%)     3753.53 (   2.50%)
Amean     fault-both-5      5054.13 (   0.00%)     5396.32 (  -6.77%)
Amean     fault-both-7      7061.77 (   0.00%)     7393.46 (  -4.70%)
Amean     fault-both-12    11560.59 (   0.00%)    12155.50 (  -5.15%)
Amean     fault-both-18    16120.15 (   0.00%)    16445.96 (  -2.02%)
Amean     fault-both-24    19804.31 (   0.00%)    20465.03 (  -3.34%)
Amean     fault-both-30    25018.73 (   0.00%)    20813.54 *  16.81%*
Amean     fault-both-32    24380.19 (   0.00%)    22384.02 (   8.19%)

The impact on the scan rates is a mixed bag because this patch is very
sensitive to timing and whether the boost was active or not. However,
detailed tracing indicated that failure of migration due to a premature
ENOMEM triggered by watermark checks were eliminated.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
---
 mm/page_alloc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 80535cd55a92..c7b80e62bfd9 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3043,7 +3043,7 @@ int __isolate_free_page(struct page *page, unsigned int order)
 		 * watermark, because we already know our high-order page
 		 * exists.
 		 */
-		watermark = min_wmark_pages(zone) + (1UL << order);
+		watermark = zone->_watermark[WMARK_MIN] + (1UL << order);
 		if (!zone_watermark_ok(zone, 0, watermark, 0, ALLOC_CMA))
 			return 0;
 
-- 
2.16.4

  parent reply	other threads:[~2018-12-14 23:03 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-14 23:02 [RFC PATCH 00/14] Increase success rates and reduce latency of compaction v1 Mel Gorman
2018-12-14 23:02 ` [PATCH 01/14] mm, compaction: Shrink compact_control Mel Gorman
2018-12-17 12:27   ` Vlastimil Babka
2018-12-14 23:02 ` [PATCH 02/14] mm, compaction: Rearrange compact_control Mel Gorman
2018-12-17 13:20   ` Vlastimil Babka
2018-12-14 23:02 ` [PATCH 03/14] mm, compaction: Remove last_migrated_pfn from compact_control Mel Gorman
2018-12-17 13:50   ` Vlastimil Babka
2018-12-14 23:03 ` [PATCH 04/14] mm, compaction: Rename map_pages to split_map_pages Mel Gorman
2018-12-17 14:06   ` Vlastimil Babka
2018-12-17 14:30     ` Mel Gorman
2018-12-14 23:03 ` [PATCH 05/14] mm, compaction: Skip pageblocks with reserved pages Mel Gorman
2018-12-18  8:08   ` Vlastimil Babka
2018-12-18  8:38     ` Mel Gorman
2018-12-14 23:03 ` [PATCH 06/14] mm, migrate: Immediately fail migration of a page with no migration handler Mel Gorman
2018-12-18  9:06   ` Vlastimil Babka
2018-12-18  9:55     ` Mel Gorman
2018-12-20 19:44   ` Yang Shi
2018-12-20 19:44     ` Yang Shi
2018-12-20 20:31     ` Mel Gorman
2018-12-14 23:03 ` [PATCH 07/14] mm, compaction: Always finish scanning of a full pageblock Mel Gorman
2018-12-18  9:23   ` Vlastimil Babka
2018-12-14 23:03 ` [PATCH 08/14] mm, compaction: Use the page allocator bulk-free helper for lists of pages Mel Gorman
2018-12-18  9:55   ` Vlastimil Babka
2018-12-19 16:04     ` Mel Gorman
2018-12-14 23:03 ` Mel Gorman [this message]
2018-12-18 12:36   ` [PATCH 09/14] mm, compaction: Ignore the fragmentation avoidance boost for isolation and compaction Vlastimil Babka
2018-12-18 13:51     ` Mel Gorman
2018-12-18 13:58       ` Vlastimil Babka
2018-12-18 14:29         ` Mel Gorman
2018-12-14 23:04 ` [PATCH 10/14] mm, compaction: Use free lists to quickly locate a migration source Mel Gorman
2018-12-14 23:05 ` [PATCH 11/14] mm, compaction: Keep migration source private to a single compaction instance Mel Gorman
2018-12-14 23:05 ` [PATCH 12/14] mm, compaction: Use free lists to quickly locate a migration target Mel Gorman
2018-12-14 23:05 ` [PATCH 13/14] mm, compaction: Capture a page under direct compaction Mel Gorman
2018-12-14 23:06 ` [PATCH 14/14] mm, compaction: Do not direct compact remote memory Mel Gorman

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