lkml.org 
[lkml]   [2011]   [Apr]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC 2/8] compaction: make isolate_lru_page with filter aware
On Wed, Apr 27, 2011 at 01:25:19AM +0900, Minchan Kim wrote:
> 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 and prevent unnecessary LRU churning.
>
> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
> Cc: Mel Gorman <mgorman@suse.de>
> Cc: Rik van Riel <riel@redhat.com>
> Cc: Andrea Arcangeli <aarcange@redhat.com>
> Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
> ---
> mm/compaction.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/mm/compaction.c b/mm/compaction.c
> index dea32e3..9f80b5a 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -335,7 +335,7 @@ static unsigned long isolate_migratepages(struct zone *zone,
> }
>
> /* Try isolate the page */
> - if (__isolate_lru_page(page, ISOLATE_BOTH, 0, 0, 0) != 0)
> + if (__isolate_lru_page(page, ISOLATE_BOTH, 0, !cc->sync, 0) != 0)
> continue;

With the suggested flags argument from 1/8, this would look like:

flags = ISOLATE_BOTH;
if (!cc->sync)
flags |= ISOLATE_CLEAN;

?

Anyway, nice change indeed!

Acked-by: Johannes Weiner <hannes@cmpxchg.org>


\
 
 \ /
  Last update: 2011-04-28 10:51    [W:0.197 / U:97.596 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site