Re: [RFC PATCH 0/5] Improve hugepage allocation success rates underload V3

From: Mel Gorman
Date: Thu Aug 09 2012 - 10:51:38 EST


On Thu, Aug 09, 2012 at 08:36:12AM -0600, Jim Schutt wrote:
> Hi Mel,
>
> On 08/09/2012 07:49 AM, Mel Gorman wrote:
> >Changelog since V2
> >o Capture !MIGRATE_MOVABLE pages where possible
> >o Document the treatment of MIGRATE_MOVABLE pages while capturing
> >o Expand changelogs
> >
> >Changelog since V1
> >o Dropped kswapd related patch, basically a no-op and regresses if fixed (minchan)
> >o Expanded changelogs a little
> >
> >Allocation success rates have been far lower since 3.4 due to commit
> >[fe2c2a10: vmscan: reclaim at order 0 when compaction is enabled]. This
> >commit was introduced for good reasons and it was known in advance that
> >the success rates would suffer but it was justified on the grounds that
> >the high allocation success rates were achieved by aggressive reclaim.
> >Success rates are expected to suffer even more in 3.6 due to commit
> >[7db8889a: mm: have order> 0 compaction start off where it left] which
> >testing has shown to severely reduce allocation success rates under load -
> >to 0% in one case. There is a proposed change to that patch in this series
> >and it would be ideal if Jim Schutt could retest the workload that led to
> >commit [7db8889a: mm: have order> 0 compaction start off where it left].
>
> I was successful at resolving my Ceph issue on 3.6-rc1, but ran
> into some other issue that isn't immediately obvious, and prevents
> me from testing your patch with 3.6-rc1. Today I will apply your
> patch series to 3.5 and test that way.
>
> Sorry for the delay.
>

No need to be sorry at all. I appreciate you taking the time and as
there were revisions since V1 you were better off waiting even if you
did not have the Ceph issue!

Thanks.

--
Mel Gorman
SUSE Labs
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