[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20120731044312.684965795@decadent.org.uk>
Date: Tue, 31 Jul 2012 05:43:19 +0100
From: Ben Hutchings <ben@...adent.org.uk>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: torvalds@...ux-foundation.org, akpm@...ux-foundation.org,
alan@...rguk.ukuu.org.uk, Mel Gorman <mgorman@...e.de>,
Rik van Riel <riel@...hat.com>,
Andrea Arcangeli <aarcange@...hat.com>,
Minchan Kim <minchan.kim@...il.com>,
Dave Jones <davej@...hat.com>, Jan Kara <jack@...e.cz>,
Andy Isaacson <adi@...apodia.org>, Nai Xia <nai.xia@...il.com>,
Johannes Weiner <jweiner@...hat.com>
Subject: [ 09/73] mm: vmscan: check if reclaim should really abort even if compaction_ready() is true for one zone
3.2-stable review patch. If anyone has any objections, please let me know.
------------------
From: Mel Gorman <mgorman@...e.de>
commit 0cee34fd72c582b4f8ad8ce00645b75fb4168199 upstream.
Stable note: Not tracked on Bugzilla. THP and compaction was found to
aggressively reclaim pages and stall systems under different
situations that was addressed piecemeal over time.
If compaction can proceed for a given zone, shrink_zones() does not
reclaim any more pages from it. After commit [e0c2327: vmscan: abort
reclaim/compaction if compaction can proceed], do_try_to_free_pages()
tries to finish as soon as possible once one zone can compact.
This was intended to prevent slabs being shrunk unnecessarily but there
are side-effects. One is that a small zone that is ready for compaction
will abort reclaim even if the chances of successfully allocating a THP
from that zone is small. It also means that reclaim can return too early
even though sc->nr_to_reclaim pages were not reclaimed.
This partially reverts the commit until it is proven that slabs are really
being shrunk unnecessarily but preserves the check to return 1 to avoid
OOM if reclaim was aborted prematurely.
[aarcange@...hat.com: This patch replaces a revert from Andrea]
Signed-off-by: Mel Gorman <mgorman@...e.de>
Reviewed-by: Rik van Riel <riel@...hat.com>
Cc: Andrea Arcangeli <aarcange@...hat.com>
Cc: Minchan Kim <minchan.kim@...il.com>
Cc: Dave Jones <davej@...hat.com>
Cc: Jan Kara <jack@...e.cz>
Cc: Andy Isaacson <adi@...apodia.org>
Cc: Nai Xia <nai.xia@...il.com>
Cc: Johannes Weiner <jweiner@...hat.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
mm/vmscan.c | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2173,7 +2173,8 @@ static inline bool compaction_ready(stru
*
* This function returns true if a zone is being reclaimed for a costly
* high-order allocation and compaction is ready to begin. This indicates to
- * the caller that it should retry the allocation or fail.
+ * the caller that it should consider retrying the allocation instead of
+ * further reclaim.
*/
static bool shrink_zones(int priority, struct zonelist *zonelist,
struct scan_control *sc)
@@ -2182,7 +2183,7 @@ static bool shrink_zones(int priority, s
struct zone *zone;
unsigned long nr_soft_reclaimed;
unsigned long nr_soft_scanned;
- bool should_abort_reclaim = false;
+ bool aborted_reclaim = false;
for_each_zone_zonelist_nodemask(zone, z, zonelist,
gfp_zone(sc->gfp_mask), sc->nodemask) {
@@ -2208,7 +2209,7 @@ static bool shrink_zones(int priority, s
* allocations.
*/
if (compaction_ready(zone, sc)) {
- should_abort_reclaim = true;
+ aborted_reclaim = true;
continue;
}
}
@@ -2230,7 +2231,7 @@ static bool shrink_zones(int priority, s
shrink_zone(priority, zone, sc);
}
- return should_abort_reclaim;
+ return aborted_reclaim;
}
static bool zone_reclaimable(struct zone *zone)
@@ -2284,7 +2285,7 @@ static unsigned long do_try_to_free_page
struct zoneref *z;
struct zone *zone;
unsigned long writeback_threshold;
- bool should_abort_reclaim;
+ bool aborted_reclaim;
get_mems_allowed();
delayacct_freepages_start();
@@ -2296,9 +2297,7 @@ static unsigned long do_try_to_free_page
sc->nr_scanned = 0;
if (!priority)
disable_swap_token(sc->mem_cgroup);
- should_abort_reclaim = shrink_zones(priority, zonelist, sc);
- if (should_abort_reclaim)
- break;
+ aborted_reclaim = shrink_zones(priority, zonelist, sc);
/*
* Don't shrink slabs when reclaiming memory from
@@ -2365,8 +2364,8 @@ out:
if (oom_killer_disabled)
return 0;
- /* Aborting reclaim to try compaction? don't OOM, then */
- if (should_abort_reclaim)
+ /* Aborted reclaim to try compaction? don't OOM, then */
+ if (aborted_reclaim)
return 1;
/* top priority shrink_zones still had more to do? don't OOM, then */
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists