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authorAndrea Arcangeli <aarcange@redhat.com>2011-03-22 16:33:11 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-03-22 17:44:05 -0700
commit11bc82d67d1150767901bca54a24466621d763d7 (patch)
tree119442c599a82b35c553c6f54626c870e885ee50 /mm/page_alloc.c
parentb2eef8c0d09101bbbff2531c097543aedde0b525 (diff)
downloadlinux-11bc82d67d1150767901bca54a24466621d763d7.tar.bz2
mm: compaction: Use async migration for __GFP_NO_KSWAPD and enforce no writeback
__GFP_NO_KSWAPD allocations are usually very expensive and not mandatory to succeed as they have graceful fallback. Waiting for I/O in those, tends to be overkill in terms of latencies, so we can reduce their latency by disabling sync migrate. Unfortunately, even with async migration it's still possible for the process to be blocked waiting for a request slot (e.g. get_request_wait in the block layer) when ->writepage is called. To prevent __GFP_NO_KSWAPD blocking, this patch prevents ->writepage being called on dirty page cache for asynchronous migration. Addresses https://bugzilla.kernel.org/show_bug.cgi?id=31142 [mel@csn.ul.ie: Avoid writebacks for NFS, retry locked pages, use bool] Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: Arthur Marsh <arthur.marsh@internode.on.net> Cc: Clemens Ladisch <cladisch@googlemail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Minchan Kim <minchan.kim@gmail.com> Reported-by: Alex Villacis Lasso <avillaci@ceibo.fiec.espol.edu.ec> Tested-by: Alex Villacis Lasso <avillaci@ceibo.fiec.espol.edu.ec> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_alloc.c')
-rw-r--r--mm/page_alloc.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 426056aff12a..6d0032bdb5d8 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2103,7 +2103,7 @@ rebalance:
sync_migration);
if (page)
goto got_pg;
- sync_migration = true;
+ sync_migration = !(gfp_mask & __GFP_NO_KSWAPD);
/* Try direct reclaim and then allocating */
page = __alloc_pages_direct_reclaim(gfp_mask, order,