From 556adecba110bf5f1db6c6b56416cfab5bcab698 Mon Sep 17 00:00:00 2001 From: Rik van Riel Date: Sat, 18 Oct 2008 20:26:34 -0700 Subject: vmscan: second chance replacement for anonymous pages We avoid evicting and scanning anonymous pages for the most part, but under some workloads we can end up with most of memory filled with anonymous pages. At that point, we suddenly need to clear the referenced bits on all of memory, which can take ages on very large memory systems. We can reduce the maximum number of pages that need to be scanned by not taking the referenced state into account when deactivating an anonymous page. After all, every anonymous page starts out referenced, so why check? If an anonymous page gets referenced again before it reaches the end of the inactive list, we move it back to the active list. To keep the maximum amount of necessary work reasonable, we scale the active to inactive ratio with the size of memory, using the formula active:inactive ratio = sqrt(memory in GB * 10). Kswapd CPU use now seems to scale by the amount of pageout bandwidth, instead of by the amount of memory present in the system. [kamezawa.hiroyu@jp.fujitsu.com: fix OOM with memcg] [kamezawa.hiroyu@jp.fujitsu.com: memcg: lru scan fix] Signed-off-by: Rik van Riel Signed-off-by: KOSAKI Motohiro Signed-off-by: KAMEZAWA Hiroyuki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mmzone.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include/linux/mmzone.h') diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 59a4c8fd6ebd..9c5111f49a32 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -323,6 +323,12 @@ struct zone { */ int prev_priority; + /* + * The target ratio of ACTIVE_ANON to INACTIVE_ANON pages on + * this zone's LRU. Maintained by the pageout code. + */ + unsigned int inactive_ratio; + ZONE_PADDING(_pad2_) /* Rarely used or read-mostly fields */ -- cgit v1.2.3