From e64c5237cf6ff474cb2f3f832f48f2b441dd9979 Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Mon, 8 Oct 2012 16:32:27 -0700 Subject: mm: compaction: abort compaction loop if lock is contended or run too long isolate_migratepages_range() might isolate no pages if for example when zone->lru_lock is contended and running asynchronous compaction. In this case, we should abort compaction, otherwise, compact_zone will run a useless loop and make zone->lru_lock is even contended. An additional check is added to ensure that cc.migratepages and cc.freepages get properly drained whan compaction is aborted. [minchan@kernel.org: Putback pages isolated for migration if aborting] [akpm@linux-foundation.org: compact_zone_order requires non-NULL arg contended] [akpm@linux-foundation.org: make compact_zone_order() require non-NULL arg `contended'] [minchan@kernel.org: Putback pages isolated for migration if aborting] Signed-off-by: Andrea Arcangeli Signed-off-by: Shaohua Li Signed-off-by: Mel Gorman Acked-by: Minchan Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/compaction.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) (limited to 'mm/compaction.c') diff --git a/mm/compaction.c b/mm/compaction.c index 1f61bcbd6262..0649cc1b3479 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -70,8 +70,7 @@ static bool compact_checklock_irqsave(spinlock_t *lock, unsigned long *flags, /* async aborts if taking too long or contended */ if (!cc->sync) { - if (cc->contended) - *cc->contended = true; + cc->contended = true; return false; } @@ -688,7 +687,7 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, /* Perform the isolation */ low_pfn = isolate_migratepages_range(zone, cc, low_pfn, end_pfn); - if (!low_pfn) + if (!low_pfn || cc->contended) return ISOLATE_ABORT; cc->migrate_pfn = low_pfn; @@ -848,6 +847,8 @@ static int compact_zone(struct zone *zone, struct compact_control *cc) switch (isolate_migratepages(zone, cc)) { case ISOLATE_ABORT: ret = COMPACT_PARTIAL; + putback_lru_pages(&cc->migratepages); + cc->nr_migratepages = 0; goto out; case ISOLATE_NONE: continue; @@ -896,6 +897,7 @@ static unsigned long compact_zone_order(struct zone *zone, bool sync, bool *contended, struct page **page) { + unsigned long ret; struct compact_control cc = { .nr_freepages = 0, .nr_migratepages = 0, @@ -903,13 +905,18 @@ static unsigned long compact_zone_order(struct zone *zone, .migratetype = allocflags_to_migratetype(gfp_mask), .zone = zone, .sync = sync, - .contended = contended, .page = page, }; INIT_LIST_HEAD(&cc.freepages); INIT_LIST_HEAD(&cc.migratepages); - return compact_zone(zone, &cc); + ret = compact_zone(zone, &cc); + + VM_BUG_ON(!list_empty(&cc.freepages)); + VM_BUG_ON(!list_empty(&cc.migratepages)); + + *contended = cc.contended; + return ret; } int sysctl_extfrag_threshold = 500; -- cgit v1.2.3