lkml.org 
[lkml]   [2014]   [Feb]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2 2/5] mm/compaction: do not call suitable_migration_target() on every page
On 02/14/2014 07:54 AM, Joonsoo Kim wrote:
> suitable_migration_target() checks that pageblock is suitable for
> migration target. In isolate_freepages_block(), it is called on every
> page and this is inefficient. So make it called once per pageblock.
>
> suitable_migration_target() also checks if page is highorder or not,
> but it's criteria for highorder is pageblock order. So calling it once
> within pageblock range has no problem.
>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

Acked-by: Vlastimil Babka <vbabka@suse.cz>

> diff --git a/mm/compaction.c b/mm/compaction.c
> index bbe1260..0d821a2 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -245,6 +245,7 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
> unsigned long nr_strict_required = end_pfn - blockpfn;
> unsigned long flags;
> bool locked = false;
> + bool checked_pageblock = false;
>
> cursor = pfn_to_page(blockpfn);
>
> @@ -275,8 +276,16 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
> break;
>
> /* Recheck this is a suitable migration target under lock */
> - if (!strict && !suitable_migration_target(page))
> - break;
> + if (!strict && !checked_pageblock) {
> + /*
> + * We need to check suitability of pageblock only once
> + * and this isolate_freepages_block() is called with
> + * pageblock range, so just check once is sufficient.
> + */
> + checked_pageblock = true;
> + if (!suitable_migration_target(page))
> + break;
> + }
>
> /* Recheck this is a buddy page under lock */
> if (!PageBuddy(page))
>



\
 
 \ /
  Last update: 2014-02-20 18:41    [W:0.071 / U:1.652 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site