This is a note to let you know that I've just added the patch titled [stable] [PATCH 3/3] mm: compaction: abort compaction if too many pages are isolated and caller is asynchronous V2
to the 2.6.39-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mm-compaction-abort-compaction-if-too-many-pages-are-isolated-and-caller-is-asynchronous-v2.patch and it can be found in the queue-2.6.39 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <sta...@kernel.org> know about it. >From mgor...@suse.de Mon Aug 1 11:42:31 2011 From: Mel Gorman <mgor...@suse.de> Date: Tue, 19 Jul 2011 10:15:51 +0100 Subject: [stable] [PATCH 3/3] mm: compaction: abort compaction if too many pages are isolated and caller is asynchronous V2 To: sta...@kernel.org Cc: Andrea Arcangeli <aarca...@redhat.com>, Andrew Morton <a...@linux-foundation.org>, Thomas Sattler <tsatt...@gmx.de>, Mel Gorman <mgor...@suse.de> Message-ID: <1311066951-25546-4-git-send-email-mgor...@suse.de> From: Mel Gorman <mgor...@suse.de> commit: f9e35b3b41f47c4e17d8132edbcab305a6aaa4b0 upstream Asynchronous compaction is used when promoting to huge pages. This is all very nice but if there are a number of processes in compacting memory, a large number of pages can be isolated. An "asynchronous" process can stall for long periods of time as a result with a user reporting that firefox can stall for 10s of seconds. This patch aborts asynchronous compaction if too many pages are isolated as it's better to fail a hugepage promotion than stall a process. [minchan....@gmail.com: return COMPACT_PARTIAL for abort] Reported-and-tested-by: Ury Stankevich <ury...@gmail.com> Signed-off-by: Mel Gorman <mgor...@suse.de> Reviewed-by: Minchan Kim <minchan....@gmail.com> Reviewed-by: Michal Hocko <mho...@suse.cz> Signed-off-by: Andrew Morton <a...@linux-foundation.org> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gre...@suse.de> --- mm/compaction.c | 29 ++++++++++++++++++++++++----- 1 file changed, 24 insertions(+), 5 deletions(-) --- a/mm/compaction.c +++ b/mm/compaction.c @@ -251,11 +251,18 @@ static bool too_many_isolated(struct zon return isolated > (inactive + active) / 2; } +/* possible outcome of isolate_migratepages */ +typedef enum { + ISOLATE_ABORT, /* Abort compaction now */ + ISOLATE_NONE, /* No pages isolated, continue scanning */ + ISOLATE_SUCCESS, /* Pages isolated, migrate */ +} isolate_migrate_t; + /* * Isolate all pages that can be migrated from the block pointed to by * the migrate scanner within compact_control. */ -static unsigned long isolate_migratepages(struct zone *zone, +static isolate_migrate_t isolate_migratepages(struct zone *zone, struct compact_control *cc) { unsigned long low_pfn, end_pfn; @@ -272,7 +279,7 @@ static unsigned long isolate_migratepage /* Do not cross the free scanner or scan within a memory hole */ if (end_pfn > cc->free_pfn || !pfn_valid(low_pfn)) { cc->migrate_pfn = end_pfn; - return 0; + return ISOLATE_NONE; } /* @@ -281,10 +288,14 @@ static unsigned long isolate_migratepage * delay for some time until fewer pages are isolated */ while (unlikely(too_many_isolated(zone))) { + /* async migration should just abort */ + if (!cc->sync) + return ISOLATE_ABORT; + congestion_wait(BLK_RW_ASYNC, HZ/10); if (fatal_signal_pending(current)) - return 0; + return ISOLATE_ABORT; } /* Time to isolate some pages for migration */ @@ -369,7 +380,7 @@ static unsigned long isolate_migratepage trace_mm_compaction_isolate_migratepages(nr_scanned, nr_isolated); - return cc->nr_migratepages; + return ISOLATE_SUCCESS; } /* @@ -533,8 +544,15 @@ static int compact_zone(struct zone *zon unsigned long nr_migrate, nr_remaining; int err; - if (!isolate_migratepages(zone, cc)) + switch (isolate_migratepages(zone, cc)) { + case ISOLATE_ABORT: + ret = COMPACT_PARTIAL; + goto out; + case ISOLATE_NONE: continue; + case ISOLATE_SUCCESS: + ; + } nr_migrate = cc->nr_migratepages; err = migrate_pages(&cc->migratepages, compaction_alloc, @@ -558,6 +576,7 @@ static int compact_zone(struct zone *zon } +out: /* Release free pages and check accounting */ cc->nr_freepages -= release_freepages(&cc->freepages); VM_BUG_ON(cc->nr_freepages != 0); Patches currently in stable-queue which might be from mgor...@suse.de are queue-2.6.39/mm-vmscan-evaluate-the-watermarks-against-the-correct.patch queue-2.6.39/mm-compaction-ensure-that-the-compaction-free-scanner-does-not-move-to-the-next-zone.patch queue-2.6.39/mm-vmscan-do-not-apply-pressure-to-slab-if-we-are-not-applying-pressure-to-zone.patch queue-2.6.39/mm-vmscan-do-not-use-page_count-without-a-page-pin.patch queue-2.6.39/vmscan-fix-a-livelock-in-kswapd.patch queue-2.6.39/mm-vmscan-correct-check-for-kswapd-sleeping-in.patch queue-2.6.39/mm-compaction-abort-compaction-if-too-many-pages-are-isolated-and-caller-is-asynchronous-v2.patch queue-2.6.39/mm-vmscan-only-read-new_classzone_idx-from-pgdat-when-reclaiming-successfully.patch _______________________________________________ stable mailing list stable@linux.kernel.org http://linux.kernel.org/mailman/listinfo/stable