mm/compaction: change the timing to check to drop the spinlock

Browse source

commit be1aa03b97 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>

...

This commit is contained in:

Joonsoo Kim 2014-04-07 15:37:05 -07:00 • committed by Greg Kroah-Hartman

parent cc85d67f4f

commit 4fff5ca780

1 changed files with 1 additions and 1 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

2

mm/compaction.c

View file