From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:51562) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TF0ko-0003e9-Sn for qemu-devel@nongnu.org; Fri, 21 Sep 2012 06:46:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TF0ki-0006wT-DR for qemu-devel@nongnu.org; Fri, 21 Sep 2012 06:46:38 -0400 Received: from cantor2.suse.de ([195.135.220.15]:47273 helo=mx2.suse.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TF0ki-0006uV-4G for qemu-devel@nongnu.org; Fri, 21 Sep 2012 06:46:32 -0400 From: Mel Gorman Date: Fri, 21 Sep 2012 11:46:18 +0100 Message-Id: <1348224383-1499-5-git-send-email-mgorman@suse.de> In-Reply-To: <1348224383-1499-1-git-send-email-mgorman@suse.de> References: <1348224383-1499-1-git-send-email-mgorman@suse.de> Subject: [Qemu-devel] [PATCH 4/9] mm: compaction: Abort compaction loop if lock is contended or run too long List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Andrew Morton Cc: Richard Davies , KVM , QEMU-devel , LKML , Linux-MM , Avi Kivity , Shaohua Li , Mel Gorman From: Shaohua Li Changelog since V2 o Fix BUG_ON triggered due to pages left on cc.migratepages o Make compact_zone_order() require non-NULL arg `contended' Changelog since V1 o only abort the compaction if lock is contended or run too long o Rearranged the code by Andrea Arcangeli. 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. [minchan@kernel.org: Putback pages isolated for migration if aborting] [akpm@linux-foundation.org: compact_zone_order requires non-NULL arg contended] Signed-off-by: Andrea Arcangeli Signed-off-by: Shaohua Li Signed-off-by: Mel Gorman Acked-by: Rik van Riel --- mm/compaction.c | 17 ++++++++++++----- mm/internal.h | 2 +- 2 files changed, 13 insertions(+), 6 deletions(-) diff --git a/mm/compaction.c b/mm/compaction.c index 614f18b..6b55491 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; } @@ -686,7 +685,7 @@ 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; @@ -846,6 +845,8 @@ 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; @@ -894,6 +895,7 @@ 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, @@ -901,13 +903,18 @@ 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; diff --git a/mm/internal.h b/mm/internal.h index 386772f..eebbed5 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -131,7 +131,7 @@ struct compact_control { int order; /* order a direct compactor needs */ int migratetype; /* MOVABLE, RECLAIMABLE etc */ struct zone *zone; - bool *contended; /* True if a lock was contended */ + bool contended; /* True if a lock was contended */ struct page **page; /* Page captured of requested size */ }; -- 1.7.9.2