Re: OOM detection regressions since 4.7

From: Markus Trippelsdorf
Date: Tue Aug 23 2016 - 03:40:22 EST


On 2016.08.23 at 09:33 +0200, Michal Hocko wrote:
> On Tue 23-08-16 13:52:45, Joonsoo Kim wrote:
> [...]
> > Hello, Michal.
> >
> > I agree with partial revert but revert should be a different form.
> > Below change try to reuse should_compact_retry() version for
> > !CONFIG_COMPACTION but it turned out that it also causes regression in
> > Markus report [1].
>
> I would argue that CONFIG_COMPACTION=n behaves so arbitrary for high
> order workloads that calling any change in that behavior a regression
> is little bit exaggerated. Disabling compaction should have a very
> strong reason. I haven't heard any so far. I am even wondering whether
> there is a legitimate reason for that these days.

BTW, the current config description:

CONFIG_COMPACTION:
Allows the compaction of memory for the allocation of huge pages.

doesn't make it clear to the user that this is an essential feature.

--
Markus