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| author | Shaohua Li <shaohua.li@intel.com> | 2011-06-15 15:08:49 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-06-15 20:04:02 -0700 |
| commit | a582a738c763e106f47eab24b8146c698a9c700b (patch) | |
| tree | aaa5eda6bae7adc04dc5cbd513f5c25ac684af97 /mm/compaction.c | |
| parent | 5db8a73a8d7cc6a66afbf25ed7fda338caa8f5f9 (diff) | |
| download | lwn-a582a738c763e106f47eab24b8146c698a9c700b.tar.gz lwn-a582a738c763e106f47eab24b8146c698a9c700b.zip | |
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.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/mm/compaction.c b/mm/compaction.c index 94bdbe1f7caf..cf7086c6dc07 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; |