From 2d1e10412c2388ff9b6afc60536eaa195a419289 Mon Sep 17 00:00:00 2001 From: Vlastimil Babka Date: Thu, 5 Nov 2015 18:48:02 -0800 Subject: [PATCH] mm, compaction: distinguish contended status in tracepoints Compaction returns prematurely with COMPACT_PARTIAL when contended or has fatal signal pending. This is ok for the callers, but might be misleading in the traces, as the usual reason to return COMPACT_PARTIAL is that we think the allocation should succeed. After this patch we distinguish the premature ending condition in the mm_compaction_finished and mm_compaction_end tracepoints. The contended status covers the following reasons: - lock contention or need_resched() detected in async compaction - fatal signal pending - too many pages isolated in the zone (only for async compaction) Further distinguishing the exact reason seems unnecessary for now. Signed-off-by: Vlastimil Babka Cc: Joonsoo Kim Cc: Mel Gorman Cc: David Rientjes Cc: Steven Rostedt Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/compaction.h | 1 + include/trace/events/compaction.h | 3 ++- mm/compaction.c | 9 ++++++--- 3 files changed, 9 insertions(+), 4 deletions(-) diff --git a/include/linux/compaction.h b/include/linux/compaction.h index f14ba98..4cd4ddf 100644 --- a/include/linux/compaction.h +++ b/include/linux/compaction.h @@ -15,6 +15,7 @@ /* For more detailed tracepoint output */ #define COMPACT_NO_SUITABLE_PAGE 5 #define COMPACT_NOT_SUITABLE_ZONE 6 +#define COMPACT_CONTENDED 7 /* When adding new states, please adjust include/trace/events/compaction.h */ /* Used to signal whether compaction detected need_sched() or lock contention */ diff --git a/include/trace/events/compaction.h b/include/trace/events/compaction.h index a43000d7..c92d1e1 100644 --- a/include/trace/events/compaction.h +++ b/include/trace/events/compaction.h @@ -16,7 +16,8 @@ EM( COMPACT_PARTIAL, "partial") \ EM( COMPACT_COMPLETE, "complete") \ EM( COMPACT_NO_SUITABLE_PAGE, "no_suitable_page") \ - EMe(COMPACT_NOT_SUITABLE_ZONE, "not_suitable_zone") + EM( COMPACT_NOT_SUITABLE_ZONE, "not_suitable_zone") \ + EMe(COMPACT_CONTENDED, "contended") #ifdef CONFIG_ZONE_DMA #define IFDEF_ZONE_DMA(X) X diff --git a/mm/compaction.c b/mm/compaction.c index a5849c4..de3e1e7 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -1202,7 +1202,7 @@ static int __compact_finished(struct zone *zone, struct compact_control *cc, unsigned long watermark; if (cc->contended || fatal_signal_pending(current)) - return COMPACT_PARTIAL; + return COMPACT_CONTENDED; /* Compaction run completes if the migrate and free scanner meet */ if (compact_scanners_met(cc)) { @@ -1393,7 +1393,7 @@ static int compact_zone(struct zone *zone, struct compact_control *cc) switch (isolate_migratepages(zone, cc)) { case ISOLATE_ABORT: - ret = COMPACT_PARTIAL; + ret = COMPACT_CONTENDED; putback_movable_pages(&cc->migratepages); cc->nr_migratepages = 0; goto out; @@ -1424,7 +1424,7 @@ static int compact_zone(struct zone *zone, struct compact_control *cc) * and we want compact_finished() to detect it */ if (err == -ENOMEM && !compact_scanners_met(cc)) { - ret = COMPACT_PARTIAL; + ret = COMPACT_CONTENDED; goto out; } } @@ -1477,6 +1477,9 @@ out: trace_mm_compaction_end(start_pfn, cc->migrate_pfn, cc->free_pfn, end_pfn, sync, ret); + if (ret == COMPACT_CONTENDED) + ret = COMPACT_PARTIAL; + return ret; } -- 2.7.4