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authorMel Gorman <mgorman@suse.de>2012-01-12 17:19:43 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-01-12 20:13:09 -0800
commita6bc32b899223a877f595ef9ddc1e89ead5072b8 (patch)
treea9529f7af2cf8e77bb6670acea32169c891a2b76 /mm/compaction.c
parent66199712e9eef5aede09dbcd9dfff87798a66917 (diff)
downloadop-kernel-dev-a6bc32b899223a877f595ef9ddc1e89ead5072b8.zip
op-kernel-dev-a6bc32b899223a877f595ef9ddc1e89ead5072b8.tar.gz
mm: compaction: introduce sync-light migration for use by compaction
This patch adds a lightweight sync migrate operation MIGRATE_SYNC_LIGHT mode that avoids writing back pages to backing storage. Async compaction maps to MIGRATE_ASYNC while sync compaction maps to MIGRATE_SYNC_LIGHT. For other migrate_pages users such as memory hotplug, MIGRATE_SYNC is used. This avoids sync compaction stalling for an excessive length of time, particularly when copying files to a USB stick where there might be a large number of dirty pages backed by a filesystem that does not support ->writepages. [aarcange@redhat.com: This patch is heavily based on Andrea's work] [akpm@linux-foundation.org: fix fs/nfs/write.c build] [akpm@linux-foundation.org: fix fs/btrfs/disk-io.c build] Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Dave Jones <davej@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Andy Isaacson <adi@hexapodia.org> Cc: Nai Xia <nai.xia@gmail.com> Cc: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/compaction.c')
-rw-r--r--mm/compaction.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/compaction.c b/mm/compaction.c
index fb29158..71a58f6 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -557,7 +557,7 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
nr_migrate = cc->nr_migratepages;
err = migrate_pages(&cc->migratepages, compaction_alloc,
(unsigned long)cc, false,
- cc->sync);
+ cc->sync ? MIGRATE_SYNC_LIGHT : MIGRATE_ASYNC);
update_nr_listpages(cc);
nr_remaining = cc->nr_migratepages;
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