vmscan: cleanup the scan batching code

The vmscan batching logic is twisting.  Move it into a standalone function
nr_scan_try_batch() and document it.  No behavior change.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Christoph Lameter <cl@linux-foundation.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index dd8487f0442f..db976b9f8791 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -334,9 +334,9 @@ struct zone {
 
         /* Fields commonly accessed by the page reclaim scanner */
         spinlock_t              lru_lock;       
-        struct {
+        struct zone_lru {
                 struct list_head list;
-                unsigned long nr_scan;
+                unsigned long nr_saved_scan;    /* accumulated for batching */
         } lru[NR_LRU_LISTS];
 
         struct zone_reclaim_stat reclaim_stat;