mm: compaction: correct the nr_strict va isolated check for CMA

Thierry reported that the "iron out" patch for isolate_freepages_block()
had problems due to the strict check being too strict with "mm:
compaction: Iron out isolate_freepages_block() and
isolate_freepages_range() -fix1".  It's possible that more pages than
necessary are isolated but the check still fails and I missed that this
fix was not picked up before RC1.  This same problem has been identified
in 3.7-RC1 by Tony Prisk and should be addressed by the following patch.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Tony Prisk <linux@prisktech.co.nz>
Reported-by: Thierry Reding <thierry.reding@avionic-design.de>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Richard Davies <richard@arachsys.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/compaction.c b/mm/compaction.c
index 2c4ce17..9eef558 100644 (file)
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -346,7 +346,7 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
         * pages requested were isolated. If there were any failures, 0 is
         * returned and CMA will fail.
         */
-       if (strict && nr_strict_required != total_isolated)
+       if (strict && nr_strict_required > total_isolated)
                total_isolated = 0;
 
        if (locked)