Re: [PATCH 0.14] oom detection rework v6

From: Michal Hocko
Date: Wed May 04 2016 - 04:50:15 EST

On Wed 04-05-16 10:12:43, Vlastimil Babka wrote:
> On 05/04/2016 07:45 AM, Joonsoo Kim wrote:
> >I still don't agree with some part of this patchset that deal with
> >!costly order. As you know, there was two regression reports from Hugh
> >and Aaron and you fixed them by ensuring to trigger compaction. I
> >think that these show the problem of this patchset. Previous kernel
> >doesn't need to ensure to trigger compaction and just works fine in
> >any case.
> IIRC previous kernel somehow subtly never OOM'd for !costly orders. So
> anything that introduces the possibility of OOM may look like regression for
> some corner case workloads.

The bug fixed by this series was COMPACTION specific because
compaction_ready is not considered otherwise.
Michal Hocko