mm: numa: limit scope of lock for NUMA migrate rate limiting
NUMA migrate rate limiting protects a migration counter and window using
a lock but in some cases this can be a contended lock. It is not
critical that the number of pages be perfect, lost updates are
acceptable. Reduce the importance of this lock.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Alex Thorlton <athorlton@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 67ab5fe..5f2052c 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -764,10 +764,7 @@
int kswapd_max_order;
enum zone_type classzone_idx;
#ifdef CONFIG_NUMA_BALANCING
- /*
- * Lock serializing the per destination node AutoNUMA memory
- * migration rate limiting data.
- */
+ /* Lock serializing the migrate rate limiting window */
spinlock_t numabalancing_migrate_lock;
/* Rate limiting time interval */