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| author | Joonsoo Kim <iamjoonsoo.kim@lge.com> | 2014-04-07 15:37:05 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-10-09 12:21:28 -0700 |
| commit | 4fff5ca78029f4df452334ecf013e53bf29079cc (patch) | |
| tree | 68d77d8cb8b21333fe5ebcc4fa89836ccdeb6d73 /mm | |
| parent | cc85d67f4fdc4fb89c74ff327d2bbe7803951a0f (diff) | |
| download | lwn-4fff5ca78029f4df452334ecf013e53bf29079cc.tar.gz lwn-4fff5ca78029f4df452334ecf013e53bf29079cc.zip | |
mm/compaction: change the timing to check to drop the spinlock
commit be1aa03b973c7dcdc576f3503f7a60429825c35d upstream.
It is odd to drop the spinlock when we scan (SWAP_CLUSTER_MAX - 1) th
pfn page. This may results in below situation while isolating
migratepage.
1. try isolate 0x0 ~ 0x200 pfn pages.
2. When low_pfn is 0x1ff, ((low_pfn+1) % SWAP_CLUSTER_MAX) == 0, so drop
the spinlock.
3. Then, to complete isolating, retry to aquire the lock.
I think that it is better to use SWAP_CLUSTER_MAX th pfn for checking the
criteria about dropping the lock. This has no harm 0x0 pfn, because, at
this time, locked variable would be false.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/compaction.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/compaction.c b/mm/compaction.c index 711ebf75b454..f347b73be165 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -487,7 +487,7 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc, cond_resched(); for (; low_pfn < end_pfn; low_pfn++) { /* give a chance to irqs before checking need_resched() */ - if (locked && !((low_pfn+1) % SWAP_CLUSTER_MAX)) { + if (locked && !(low_pfn % SWAP_CLUSTER_MAX)) { if (should_release_lock(&zone->lru_lock)) { spin_unlock_irqrestore(&zone->lru_lock, flags); locked = false; |