]> git.karo-electronics.de Git - karo-tx-linux.git/commit
mm: compaction: make isolate_lru_page() filter-aware
authorMinchan Kim <minchan.kim@gmail.com>
Tue, 1 Nov 2011 00:06:51 +0000 (17:06 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 1 Aug 2012 19:27:16 +0000 (12:27 -0700)
commit19faec0520b3b16dfd58cde30938a3c4d3dcdd5b
tree1a32165e3bd19c2b167e23c92f8dede9fe883ed2
parenta15a3971cc49eefbde40b397a446c0fa9c5fed9c
mm: compaction: make isolate_lru_page() filter-aware

commit 39deaf8585152f1a35c1676d3d7dc6ae0fb65967 upstream.

Stable note: Not tracked in Bugzilla. THP and compaction disrupt the LRU
list leading to poor reclaim decisions which has a variable
performance impact.

In async mode, compaction doesn't migrate dirty or writeback pages.  So,
it's meaningless to pick the page and re-add it to lru list.

Of course, when we isolate the page in compaction, the page might be dirty
or writeback but when we try to migrate the page, the page would be not
dirty, writeback.  So it could be migrated.  But it's very unlikely as
isolate and migration cycle is much faster than writeout.

So, this patch helps cpu overhead and prevent unnecessary LRU churning.

Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
include/linux/mmzone.h
mm/compaction.c
mm/vmscan.c