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authorShaohua Li <shaohua.li@intel.com>2011-06-15 15:08:49 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-06-15 20:04:02 -0700
commita582a738c763e106f47eab24b8146c698a9c700b (patch)
treeaaa5eda6bae7adc04dc5cbd513f5c25ac684af97 /mm/compaction.c
parent5db8a73a8d7cc6a66afbf25ed7fda338caa8f5f9 (diff)
compaction: checks correct fragmentation index
fragmentation_index() returns -1000 when the allocation might succeed This doesn't match the comment and code in compaction_suitable(). I thought compaction_suitable should return COMPACT_PARTIAL in -1000 case, because in this case allocation could succeed depending on watermarks. The impact of this is that compaction starts and compact_finished() is called which rechecks the watermarks and the free lists. It should have the same result in that compaction should not start but is more expensive. Acked-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Shaohua Li <shaohua.li@intel.com> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/compaction.c')
-rw-r--r--mm/compaction.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/mm/compaction.c b/mm/compaction.c
index 94bdbe1f7ca..cf7086c6dc0 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -480,7 +480,8 @@ unsigned long compaction_suitable(struct zone *zone, int order)
* fragmentation index determines if allocation failures are due to
* low memory or external fragmentation
*
- * index of -1 implies allocations might succeed dependingon watermarks
+ * index of -1000 implies allocations might succeed depending on
+ * watermarks
* index towards 0 implies failure is due to lack of memory
* index towards 1000 implies failure is due to fragmentation
*
@@ -490,7 +491,8 @@ unsigned long compaction_suitable(struct zone *zone, int order)
if (fragindex >= 0 && fragindex <= sysctl_extfrag_threshold)
return COMPACT_SKIPPED;
- if (fragindex == -1 && zone_watermark_ok(zone, order, watermark, 0, 0))
+ if (fragindex == -1000 && zone_watermark_ok(zone, order, watermark,
+ 0, 0))
return COMPACT_PARTIAL;
return COMPACT_CONTINUE;