The patch titled
mm: compaction: do not compact within a preferred zone after a compaction failure
has been added to the -mm tree. Its filename is
mm-compaction-do-not-compact-within-a-preferred-zone-after-a-compaction-failure.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: mm: compaction: do not compact within a preferred zone after a compaction failure
From: Mel Gorman <mel@xxxxxxxxx>
The fragmentation index may indicate that a failure is due to external
fragmentation but after a compaction run completes, it is still possible
for an allocation to fail. There are two obvious reasons as to why
o Page migration cannot move all pages so fragmentation remains
o A suitable page may exist but watermarks are not met
In the event of compaction followed by an allocation failure, this patch
defers further compaction in the zone for a period of time. The zone that
is deferred is the first zone in the zonelist - i.e. the preferred zone.
To defer compaction in the other zones, the information would need to be
stored in the zonelist or implemented similar to the zonelist_cache. This
would impact the fast-paths and is not justified at this time.
Signed-off-by: Mel Gorman <mel@xxxxxxxxx>
Acked-by: Rik van Riel <riel@xxxxxxxxxx>
Cc: Minchan Kim <minchan.kim@xxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/compaction.h | 35 +++++++++++++++++++++++++++++++++++
include/linux/mmzone.h | 7 +++++++
mm/page_alloc.c | 5 ++++-
3 files changed, 46 insertions(+), 1 deletion(-)
diff -puN include/linux/compaction.h~mm-compaction-do-not-compact-within-a-preferred-zone-after-a-compaction-failure include/linux/compaction.h
--- a/include/linux/compaction.h~mm-compaction-do-not-compact-within-a-preferred-zone-after-a-compaction-failure
+++ a/include/linux/compaction.h
@@ -18,6 +18,32 @@ extern int sysctl_extfrag_handler(struct
extern int fragmentation_index(struct zone *zone, unsigned int order);
extern unsigned long try_to_compact_pages(struct zonelist *zonelist,
int order, gfp_t gfp_mask, nodemask_t *mask);
+
+/* defer_compaction - Do not compact within a zone until a given time */
+static inline void defer_compaction(struct zone *zone, unsigned long resume)
+{
+ /*
+ * This function is called when compaction fails to result in a page
+ * allocation success. This is somewhat unsatisfactory as the failure
+ * to compact has nothing to do with time and everything to do with
+ * the requested order, the number of free pages and watermarks. How
+ * to wait on that is more unclear, but the answer would apply to
+ * other areas where the VM waits based on time.
+ */
+ zone->compact_resume = resume;
+}
+
+static inline int compaction_deferred(struct zone *zone)
+{
+ /* init once if necessary */
+ if (unlikely(!zone->compact_resume)) {
+ zone->compact_resume = jiffies;
+ return 0;
+ }
+
+ return time_before(jiffies, zone->compact_resume);
+}
+
#else
static inline unsigned long try_to_compact_pages(struct zonelist *zonelist,
int order, gfp_t gfp_mask, nodemask_t *nodemask)
@@ -25,6 +51,15 @@ static inline unsigned long try_to_compa
return COMPACT_INCOMPLETE;
}
+static inline void defer_compaction(struct zone *zone, unsigned long resume)
+{
+}
+
+static inline int compaction_deferred(struct zone *zone)
+{
+ return 1;
+}
+
#endif /* CONFIG_COMPACTION */
#if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
diff -puN include/linux/mmzone.h~mm-compaction-do-not-compact-within-a-preferred-zone-after-a-compaction-failure include/linux/mmzone.h
--- a/include/linux/mmzone.h~mm-compaction-do-not-compact-within-a-preferred-zone-after-a-compaction-failure
+++ a/include/linux/mmzone.h
@@ -321,6 +321,13 @@ struct zone {
unsigned long *pageblock_flags;
#endif /* CONFIG_SPARSEMEM */
+#ifdef CONFIG_COMPACTION
+ /*
+ * If a compaction fails, do not try compaction again until
+ * jiffies is after the value of compact_resume
+ */
+ unsigned long compact_resume;
+#endif
ZONE_PADDING(_pad1_)
diff -puN mm/page_alloc.c~mm-compaction-do-not-compact-within-a-preferred-zone-after-a-compaction-failure mm/page_alloc.c
--- a/mm/page_alloc.c~mm-compaction-do-not-compact-within-a-preferred-zone-after-a-compaction-failure
+++ a/mm/page_alloc.c
@@ -1770,7 +1770,7 @@ __alloc_pages_direct_reclaim(gfp_t gfp_m
cond_resched();
/* Try memory compaction for high-order allocations before reclaim */
- if (order) {
+ if (order && !compaction_deferred(preferred_zone)) {
*did_some_progress = try_to_compact_pages(zonelist,
order, gfp_mask, nodemask);
if (*did_some_progress != COMPACT_SKIPPED) {
@@ -1795,6 +1795,9 @@ __alloc_pages_direct_reclaim(gfp_t gfp_m
*/
count_vm_event(COMPACTFAIL);
+ /* On failure, avoid compaction for a short time. */
+ defer_compaction(preferred_zone, jiffies + HZ/50);
+
cond_resched();
}
}
_
Patches currently in -mm which might be from mel@xxxxxxxxx are
page-allocator-reduce-fragmentation-in-buddy-allocator-by-adding-buddies-that-are-merging-to-the-tail-of-the-free-lists.patch
mempolicy-remove-redundant-code.patch
mm-default-to-node-zonelist-ordering-when-nodes-have-only-lowmem.patch
mm-migration-take-a-reference-to-the-anon_vma-before-migrating.patch
mm-migration-do-not-try-to-migrate-unmapped-anonymous-pages.patch
mm-share-the-anon_vma-ref-counts-between-ksm-and-page-migration.patch
mm-allow-config_migration-to-be-set-without-config_numa-or-memory-hot-remove.patch
mm-export-unusable-free-space-index-via-proc-unusable_index.patch
mm-export-fragmentation-index-via-proc-extfrag_index.patch
mm-move-definition-for-lru-isolation-modes-to-a-header.patch
mm-compaction-memory-compaction-core.patch
mm-compaction-add-proc-trigger-for-memory-compaction.patch
mm-compaction-add-sys-trigger-for-per-node-memory-compaction.patch
mm-compaction-direct-compact-when-a-high-order-allocation-fails.patch
mm-compaction-add-a-tunable-that-decides-when-memory-should-be-compacted-and-when-it-should-be-reclaimed.patch
mm-compaction-do-not-compact-within-a-preferred-zone-after-a-compaction-failure.patch
mm-migration-allow-the-migration-of-pageswapcache-pages.patch
delay-accounting-re-implement-c-for-getdelaysc-to-report-information-on-a-target-command.patch
delay-accounting-re-implement-c-for-getdelaysc-to-report-information-on-a-target-command-checkpatch-fixes.patch
add-debugging-aid-for-memory-initialisation-problems.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
