vmscan: kill unnecessary prefetch

The pages in the list passed move_active_pages_to_lru() are already
touched by shrink_active_list().  IOW the prefetch in
move_active_pages_to_lru() don't populate any cache.  it's pointless.

This patch remove it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 20c5fa8..e219b47 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1273,7 +1273,6 @@ static void move_active_pages_to_lru(struct zone *zone,
 
        while (!list_empty(list)) {
                page = lru_to_page(list);
-               prefetchw_prev_lru_page(page, list, flags);
 
                VM_BUG_ON(PageLRU(page));
                SetPageLRU(page);