Re: [RFC PATCH 0/5] Improve hugepage allocation success ratesunder load V3

From: Jim Schutt
Date: Thu Aug 09 2012 - 10:36:29 EST


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.

-- Jim

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