vmscan: avoid setting zone congested if no page dirty

nr_dirty and nr_congested are increased only when the page is dirty. So if all pages are clean, both them will be zero. In this case, we should not mark the zone congested. Signed-off-by: Shaohua Li <[email protected]> Reviewed-by: Johannes Weiner <[email protected]> Reviewed-by: Minchan Kim <[email protected]> Acked-by: Mel Gorman <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
iegor · Nov 12, 2010 · 1dce071 · 1dce071
1 parent 3871525
commit 1dce071
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/mm/vmscan.c b/mm/vmscan.c
@@ -913,7 +913,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
 	 * back off and wait for congestion to clear because further reclaim
 	 * will encounter the same problem
 	 */
-	if (nr_dirty == nr_congested)
+	if (nr_dirty == nr_congested && nr_dirty != 0)
 		zone_set_flag(zone, ZONE_CONGESTED);
 
 	free_page_list(&free_pages);