The patch titled
Subject: mm, compaction: make full priority ignore pageblock suitability
has been added to the -mm tree. Its filename is
mm-compaction-make-full-priority-ignore-pageblock-suitability.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-compaction-make-full-priority-ignore-pageblock-suitability.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-compaction-make-full-priority-ignore-pageblock-suitability.patch
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------------------------------------------------------
From: Vlastimil Babka <vbabka@xxxxxxx>
Subject: mm, compaction: make full priority ignore pageblock suitability
Several people have reported premature OOMs for order-2 allocations
(stack) due to OOM rework in 4.7. In the scenario (parallel kernel build
and dd writing to two drives) many pageblocks get marked as Unmovable and
compaction free scanner struggles to isolate free pages. Joonsoo Kim
pointed out that the free scanner skips pageblocks that are not movable to
prevent filling them and forcing non-movable allocations to fallback to
other pageblocks. Such heuristic makes sense to help prevent long-term
fragmentation, but premature OOMs are relatively more urgent problem. As
a compromise, this patch disables the heuristic only for the ultimate
compaction priority.
Link: http://lkml.kernel.org/r/20160906135258.18335-5-vbabka@xxxxxxx
Reported-by: Ralf-Peter Rohbeck <Ralf-Peter.Rohbeck@xxxxxxxxxxx>
Reported-by: Arkadiusz Miskiewicz <a.miskiewicz@xxxxxxxxx>
Reported-by: Olaf Hering <olaf@xxxxxxxxx>
Suggested-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/compaction.c | 11 ++++++++---
mm/internal.h | 1 +
2 files changed, 9 insertions(+), 3 deletions(-)
diff -puN mm/compaction.c~mm-compaction-make-full-priority-ignore-pageblock-suitability mm/compaction.c
--- a/mm/compaction.c~mm-compaction-make-full-priority-ignore-pageblock-suitability
+++ a/mm/compaction.c
@@ -997,8 +997,12 @@ isolate_migratepages_range(struct compac
#ifdef CONFIG_COMPACTION
/* Returns true if the page is within a block suitable for migration to */
-static bool suitable_migration_target(struct page *page)
+static bool suitable_migration_target(struct compact_control *cc,
+ struct page *page)
{
+ if (cc->ignore_block_suitable)
+ return true;
+
/* If the page is a large free page, then disallow migration */
if (PageBuddy(page)) {
/*
@@ -1083,7 +1087,7 @@ static void isolate_freepages(struct com
continue;
/* Check the block is suitable for migration */
- if (!suitable_migration_target(page))
+ if (!suitable_migration_target(cc, page))
continue;
/* If isolation recently failed, do not retry */
@@ -1656,7 +1660,8 @@ static enum compact_result compact_zone_
.classzone_idx = classzone_idx,
.direct_compaction = true,
.whole_zone = (prio == MIN_COMPACT_PRIORITY),
- .ignore_skip_hint = (prio == MIN_COMPACT_PRIORITY)
+ .ignore_skip_hint = (prio == MIN_COMPACT_PRIORITY),
+ .ignore_block_suitable = (prio == MIN_COMPACT_PRIORITY)
};
INIT_LIST_HEAD(&cc.freepages);
INIT_LIST_HEAD(&cc.migratepages);
diff -puN mm/internal.h~mm-compaction-make-full-priority-ignore-pageblock-suitability mm/internal.h
--- a/mm/internal.h~mm-compaction-make-full-priority-ignore-pageblock-suitability
+++ a/mm/internal.h
@@ -178,6 +178,7 @@ struct compact_control {
unsigned long last_migrated_pfn;/* Not yet flushed page being freed */
enum migrate_mode mode; /* Async or sync migration mode */
bool ignore_skip_hint; /* Scan blocks even if marked skip */
+ bool ignore_block_suitable; /* Scan blocks considered unsuitable */
bool direct_compaction; /* False from kcompactd or /proc/... */
bool whole_zone; /* Whole zone should/has been scanned */
int order; /* order a direct compactor needs */
_
Patches currently in -mm which might be from vbabka@xxxxxxx are
mm-compaction-make-whole_zone-flag-ignore-cached-scanner-positions.patch
mm-compaction-cleanup-unused-functions.patch
mm-compaction-rename-compact_partial-to-compact_success.patch
mm-compaction-dont-recheck-watermarks-after-compact_success.patch
mm-compaction-add-the-ultimate-direct-compaction-priority.patch
mm-compaction-add-the-ultimate-direct-compaction-priority-fix.patch
mm-compaction-use-correct-watermark-when-checking-compaction-success.patch
mm-compaction-create-compact_gap-wrapper.patch
mm-compaction-create-compact_gap-wrapper-fix.patch
mm-compaction-use-proper-alloc_flags-in-__compaction_suitable.patch
mm-compaction-require-only-min-watermarks-for-non-costly-orders.patch
mm-compaction-require-only-min-watermarks-for-non-costly-orders-fix.patch
mm-vmscan-make-compaction_ready-more-accurate-and-readable.patch
revert-mm-oom-prevent-premature-oom-killer-invocation-for-high-order-request.patch
mm-compaction-more-reliably-increase-direct-compaction-priority.patch
mm-compaction-restrict-full-priority-to-non-costly-orders.patch
mm-compaction-make-full-priority-ignore-pageblock-suitability.patch
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