lkml.org 
[lkml]   [2012]   [Sep]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 2/2] mm: support MIGRATE_DISCARD
On Wed, Sep 05, 2012 at 05:11:13PM +0900, Minchan Kim wrote:
> This patch introudes MIGRATE_DISCARD mode in migration.
> It drops *clean cache pages* instead of migration so that
> migration latency could be reduced by avoiding (memcpy + page remapping).
> It's useful for CMA because latency of migration is very important rather
> than eviction of background processes's workingset. In addition, it needs
> less free pages for migration targets so it could avoid memory reclaiming
> to get free pages, which is another factor increase latency.
>

Bah, this was released while I was reviewing the older version. I did
not read this one as closely but I see the enum problems have gone away
at least. I'd still prefer if CMA had an additional helper to discard
some pages with shrink_page_list() and migrate the remaining pages with
migrate_pages(). That would remove the need to add a MIGRATE_DISCARD
migrate mode at all.

--
Mel Gorman
SUSE Labs


\
 
 \ /
  Last update: 2012-09-05 13:42    [W:0.068 / U:0.140 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site