From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx149.postini.com [74.125.245.149]) by kanga.kvack.org (Postfix) with SMTP id 5E2EE6B005D for ; Sun, 9 Sep 2012 21:18:37 -0400 (EDT) Received: by dadi14 with SMTP id i14so1166465dad.14 for ; Sun, 09 Sep 2012 18:18:36 -0700 (PDT) Date: Mon, 10 Sep 2012 09:18:30 +0800 From: Shaohua Li Subject: [patch 1/2 v2]compaction: abort compaction loop if lock is contended or run too long Message-ID: <20120910011830.GC3715@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org Cc: akpm@linux-foundation.org, mgorman@suse.de, aarcange@redhat.com isolate_migratepages_range() might isolate none pages, for example, when zone->lru_lock is contended and compaction is async. In this case, we should abort compaction, otherwise, compact_zone will run a useless loop and make zone->lru_lock is even contended. V2: only abort the compaction if lock is contended or run too long Rearranged the code by Andrea Arcangeli. Signed-off-by: Andrea Arcangeli Signed-off-by: Shaohua Li --- mm/compaction.c | 12 +++++++----- mm/internal.h | 2 +- 2 files changed, 8 insertions(+), 6 deletions(-) Index: linux/mm/compaction.c =================================================================== --- linux.orig/mm/compaction.c 2012-09-06 18:37:52.636413761 +0800 +++ linux/mm/compaction.c 2012-09-10 08:49:40.377869710 +0800 @@ -70,8 +70,7 @@ static bool compact_checklock_irqsave(sp /* async aborts if taking too long or contended */ if (!cc->sync) { - if (cc->contended) - *cc->contended = true; + cc->contended = true; return false; } @@ -634,7 +633,7 @@ static isolate_migrate_t isolate_migrate /* 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; @@ -831,6 +830,7 @@ static unsigned long compact_zone_order( int order, gfp_t gfp_mask, bool sync, bool *contended) { + unsigned long ret; struct compact_control cc = { .nr_freepages = 0, .nr_migratepages = 0, @@ -838,12 +838,14 @@ static unsigned long compact_zone_order( .migratetype = allocflags_to_migratetype(gfp_mask), .zone = zone, .sync = sync, - .contended = contended, }; INIT_LIST_HEAD(&cc.freepages); INIT_LIST_HEAD(&cc.migratepages); - return compact_zone(zone, &cc); + ret = compact_zone(zone, &cc); + if (contended) + *contended = cc.contended; + return ret; } int sysctl_extfrag_threshold = 500; Index: linux/mm/internal.h =================================================================== --- linux.orig/mm/internal.h 2012-09-03 15:16:30.566299444 +0800 +++ linux/mm/internal.h 2012-09-10 08:45:41.980866645 +0800 @@ -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 */ }; unsigned long -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org