Re: [PATCH 3/7] mm/page_alloc: Explicitly record high-order atomic allocations in alloc_flags

Mel Gorman
2023-01-12T09:42:18Z

On Wed, Jan 11, 2023 at 04:36:01PM +0100, Michal Hocko wrote:
> On Mon 09-01-23 15:16:27, Mel Gorman wrote:
> > A high-order ALLOC_HARDER allocation is assumed to be atomic. While that
> > is accurate, it changes later in the series. In preparation, explicitly
> > record high-order atomic allocations in gfp_to_alloc_flags(). There is
> > a slight functional change in that OOM handling avoids using high-order
> > reserve until it has to.
>
> I do not follow the oom handling part. IIRC we are dropping highatomic
> reserves before triggering oom. Something might have changed down the
> path but I can still see unreserve_highatomic_pageblock in
> should_reclaim_retry.
>

That comment is now stale and should be removed because I fixed up the
OOM oddities. At this point, a series resubmission is needed because a
few changelogs have to be updated.

--
Mel Gorman
SUSE Labs