lkml.org 
[lkml]   [2016]   [Mar]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 0/3] OOM detection rework v4
On Wed 02-03-16 11:55:07, Joonsoo Kim wrote:
> On Tue, Mar 01, 2016 at 07:14:08PM +0100, Vlastimil Babka wrote:
[...]
> > Yes, compaction is historically quite careful to avoid making low
> > memory conditions worse, and to prevent work if it doesn't look like
> > it can ultimately succeed the allocation (so having not enough base
> > pages means that compacting them is considered pointless). This
> > aspect of preventing non-zero-order OOMs is somewhat unexpected :)
>
> It's better not to assume that compaction would succeed all the times.
> Compaction has some limitations so it sometimes fails.
> For example, in lowmem situation, it only scans small parts of memory
> and if that part is fragmented by non-movable page, compaction would fail.
> And, compaction would defer requests 64 times at maximum if successive
> compaction failure happens before.
>
> Depending on compaction heavily is right direction to go but I think
> that it's not ready for now. More reclaim would relieve problem.

I really fail to see why. The reclaimable memory can be migrated as
well, no? Relying on the order-0 reclaim makes only sense to get over
wmarks.

--
Michal Hocko
SUSE Labs

\
 
 \ /
  Last update: 2016-03-02 14:01    [W:0.022 / U:0.260 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site