mm: compaction: introduce sync-light migration for use by compaction
authorMel Gorman <mgorman@suse.de>
Fri, 13 Jan 2012 01:19:43 +0000 (17:19 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 13 Jan 2012 04:13:09 +0000 (20:13 -0800)
commita6bc32b899223a877f595ef9ddc1e89ead5072b8
treea9529f7af2cf8e77bb6670acea32169c891a2b76
parent66199712e9eef5aede09dbcd9dfff87798a66917
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>
fs/btrfs/disk-io.c
fs/hugetlbfs/inode.c
fs/nfs/internal.h
fs/nfs/write.c
include/linux/fs.h
include/linux/migrate.h
mm/compaction.c
mm/memory-failure.c
mm/memory_hotplug.c
mm/mempolicy.c
mm/migrate.c