The patch titled
Subject: mm: vmscan: check if reclaim should really abort even if compaction_ready() is true for one zone
has been removed from the -mm tree. Its filename was
mm-vmscan-check-if-reclaim-should-really-abort-even-if-compaction_ready-is-true-for-one-zone.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
From: Mel Gorman <mgorman@xxxxxxx>
Subject: mm: vmscan: check if reclaim should really abort even if compaction_ready() is true for one zone
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@xxxxxxxxxx: This patch replaces a revert from Andrea]
Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Minchan Kim <minchan.kim@xxxxxxxxx>
Cc: Dave Jones <davej@xxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Andy Isaacson <adi@xxxxxxxxxxxxx>
Cc: Nai Xia <nai.xia@xxxxxxxxx>
Cc: Johannes Weiner <jweiner@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)
diff -puN mm/vmscan.c~mm-vmscan-check-if-reclaim-should-really-abort-even-if-compaction_ready-is-true-for-one-zone mm/vmscan.c
--- a/mm/vmscan.c~mm-vmscan-check-if-reclaim-should-really-abort-even-if-compaction_ready-is-true-for-one-zone
+++ a/mm/vmscan.c
@@ -2217,7 +2217,8 @@ 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)
@@ -2226,7 +2227,7 @@ 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) {
@@ -2252,7 +2253,7 @@ static bool shrink_zones(int priority, s
* allocations.
*/
if (compaction_ready(zone, sc)) {
- should_abort_reclaim = true;
+ aborted_reclaim = true;
continue;
}
}
@@ -2274,7 +2275,7 @@ 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)
@@ -2328,7 +2329,7 @@ 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();
@@ -2340,9 +2341,7 @@ static unsigned long do_try_to_free_page
sc->nr_scanned = 0;
if (!priority)
disable_swap_token(sc->target_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
@@ -2409,8 +2408,8 @@ 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 */
_
Patches currently in -mm which might be from mgorman@xxxxxxx are
origin.patch
mm-fix-null-ptr-dereference-in-__count_immobile_pages.patch
mm-__count_immobile_pages-make-sure-the-node-is-online.patch
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