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Groups > linux.kernel > #1459887
| From | Vlastimil Babka <vbabka@suse.cz> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH v6 07/11] mm, compaction: use correct watermark when checking compaction success |
| Date | 2016-08-10 22:50 +0200 |
| Message-ID | <s4IBQ-1DK-31@gated-at.bofh.it> (permalink) |
| References | <s4GgI-79-119@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
The __compact_finished() function uses low watermark in a check that has to pass if the direct compaction is to finish and allocation should succeed. This is too pessimistic, as the allocation will typically use min watermark. It may happen that during compaction, we drop below the low watermark (due to parallel activity), but still form the target high-order page. By checking against low watermark, we might needlessly continue compaction. Similarly, __compaction_suitable() uses low watermark in a check whether allocation can succeed without compaction. Again, this is unnecessarily pessimistic. After this patch, these check will use direct compactor's alloc_flags to determine the watermark, which is effectively the min watermark. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> --- mm/compaction.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/mm/compaction.c b/mm/compaction.c index ae4f40afcca1..9bd788886b1a 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -1316,7 +1316,7 @@ static enum compact_result __compact_finished(struct zone *zone, struct compact_ return COMPACT_CONTINUE; /* Compaction run is not finished if the watermark is not met */ - watermark = low_wmark_pages(zone); + watermark = zone->watermark[cc->alloc_flags & ALLOC_WMARK_MASK]; if (!zone_watermark_ok(zone, cc->order, watermark, cc->classzone_idx, cc->alloc_flags)) @@ -1381,7 +1381,7 @@ static enum compact_result __compaction_suitable(struct zone *zone, int order, if (is_via_compact_memory(order)) return COMPACT_CONTINUE; - watermark = low_wmark_pages(zone); + watermark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK]; /* * If watermarks for high-order allocation are already met, there * should be no need for compaction at all. @@ -1395,7 +1395,7 @@ static enum compact_result __compaction_suitable(struct zone *zone, int order, * This is because during migration, copies of pages need to be * allocated and for a short time, the footprint is higher */ - watermark += (2UL << order); + watermark = low_wmark_pages(zone) + (2UL << order); if (!__zone_watermark_ok(zone, 0, watermark, classzone_idx, alloc_flags, wmark_target)) return COMPACT_SKIPPED; -- 2.9.2
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[PATCH v6 00/11] make direct compaction more deterministic Vlastimil Babka <vbabka@suse.cz> - 2016-08-10 20:20 +0200
[PATCH v6 06/11] mm, compaction: more reliably increase direct compaction priority Vlastimil Babka <vbabka@suse.cz> - 2016-08-10 22:50 +0200
Re: [PATCH v6 06/11] mm, compaction: more reliably increase direct compaction priority Joonsoo Kim <iamjoonsoo.kim@lge.com> - 2016-08-16 08:10 +0200
Re: [PATCH v6 06/11] mm, compaction: more reliably increase direct compaction priority Vlastimil Babka <vbabka@suse.cz> - 2016-08-16 08:40 +0200
Re: [PATCH v6 06/11] mm, compaction: more reliably increase direct compaction priority Michal Hocko <mhocko@kernel.org> - 2016-08-18 11:20 +0200
Re: [PATCH v6 06/11] mm, compaction: more reliably increase direct compaction priority Vlastimil Babka <vbabka@suse.cz> - 2016-08-18 11:50 +0200
Re: [PATCH v6 06/11] mm, compaction: more reliably increase direct compaction priority Michal Hocko <mhocko@kernel.org> - 2016-08-18 12:00 +0200
[PATCH v6 09/11] mm, compaction: use proper alloc_flags in __compaction_suitable() Vlastimil Babka <vbabka@suse.cz> - 2016-08-10 22:50 +0200
[PATCH v6 01/11] mm, compaction: make whole_zone flag ignore cached scanner positions Vlastimil Babka <vbabka@suse.cz> - 2016-08-10 22:50 +0200
[PATCH v6 07/11] mm, compaction: use correct watermark when checking compaction success Vlastimil Babka <vbabka@suse.cz> - 2016-08-10 22:50 +0200
[PATCH v6 08/11] mm, compaction: create compact_gap wrapper Vlastimil Babka <vbabka@suse.cz> - 2016-08-10 22:50 +0200
Re: [PATCH v6 08/11] mm, compaction: create compact_gap wrapper Vlastimil Babka <vbabka@suse.cz> - 2016-08-16 08:20 +0200
Re: [PATCH v6 08/11] mm, compaction: create compact_gap wrapper Joonsoo Kim <iamjoonsoo.kim@lge.com> - 2016-08-16 08:40 +0200
Re: [PATCH v6 08/11] mm, compaction: create compact_gap wrapper Vlastimil Babka <vbabka@suse.cz> - 2016-08-18 14:20 +0200
Re: [PATCH v6 08/11] mm, compaction: create compact_gap wrapper Joonsoo Kim <iamjoonsoo.kim@lge.com> - 2016-08-16 08:20 +0200
[PATCH v6 03/11] mm, compaction: rename COMPACT_PARTIAL to COMPACT_SUCCESS Vlastimil Babka <vbabka@suse.cz> - 2016-08-10 22:50 +0200
Re: [PATCH v6 03/11] mm, compaction: rename COMPACT_PARTIAL to COMPACT_SUCCESS Michal Hocko <mhocko@kernel.org> - 2016-08-18 13:10 +0200
[PATCH v6 02/11] mm, compaction: cleanup unused functions Vlastimil Babka <vbabka@suse.cz> - 2016-08-10 23:30 +0200
[PATCH v6 10/11] mm, compaction: require only min watermarks for non-costly orders Vlastimil Babka <vbabka@suse.cz> - 2016-08-10 23:30 +0200
Re: [PATCH v6 10/11] mm, compaction: require only min watermarks for non-costly orders Joonsoo Kim <iamjoonsoo.kim@lge.com> - 2016-08-16 08:20 +0200
Re: [PATCH v6 10/11] mm, compaction: require only min watermarks for non-costly orders Vlastimil Babka <vbabka@suse.cz> - 2016-08-16 08:40 +0200
Re: [PATCH v6 10/11] mm, compaction: require only min watermarks for non-costly orders Joonsoo Kim <iamjoonsoo.kim@lge.com> - 2016-08-16 08:50 +0200
Re: [PATCH v6 10/11] mm, compaction: require only min watermarks for non-costly orders Vlastimil Babka <vbabka@suse.cz> - 2016-08-18 14:30 +0200
[PATCH v6 05/11] mm, compaction: add the ultimate direct compaction priority Vlastimil Babka <vbabka@suse.cz> - 2016-08-10 23:30 +0200
Re: [PATCH v6 05/11] mm, compaction: add the ultimate direct compaction priority Joonsoo Kim <iamjoonsoo.kim@lge.com> - 2016-08-16 08:00 +0200
Re: [PATCH v6 05/11] mm, compaction: add the ultimate direct compaction priority Vlastimil Babka <vbabka@suse.cz> - 2016-08-18 14:30 +0200
[PATCH v6 11/11] mm, vmscan: make compaction_ready() more accurate and readable Vlastimil Babka <vbabka@suse.cz> - 2016-08-10 23:30 +0200
[PATCH v6 04/11] mm, compaction: don't recheck watermarks after COMPACT_SUCCESS Vlastimil Babka <vbabka@suse.cz> - 2016-08-10 23:30 +0200
Re: [PATCH v6 04/11] mm, compaction: don't recheck watermarks after COMPACT_SUCCESS Joonsoo Kim <iamjoonsoo.kim@lge.com> - 2016-08-16 08:10 +0200
Re: [PATCH v6 04/11] mm, compaction: don't recheck watermarks after COMPACT_SUCCESS Vlastimil Babka <vbabka@suse.cz> - 2016-08-16 08:20 +0200
Re: [PATCH v6 04/11] mm, compaction: don't recheck watermarks after COMPACT_SUCCESS Vlastimil Babka <vbabka@suse.cz> - 2016-08-18 14:00 +0200
Re: [PATCH v6 04/11] mm, compaction: don't recheck watermarks after COMPACT_SUCCESS Michal Hocko <mhocko@kernel.org> - 2016-08-18 11:10 +0200
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