On Tue, Mar 01, 2011 at 09:57:59PM -0800, Andrew Morton wrote:

On Wed, 2 Mar 2011 06:52:21 +0100 Andrea Arcangeli [off-list ref] wrote:

quoted

These are the other two patches that are needed for both workloads to
be better than before.

mm-compaction-minimise-the-time-irqs-are-disabled-while-isolating-pages-for-migration
mm-compaction-minimise-the-time-irqs-are-disabled-while-isolating-free-pages

I have those queued for 2.6.39 - they didn't seem terribly critical and
no mention of NMI watchdog timeouts was made.

Guys, this stuff matters :(  Should both go into 2.6.38?  If so, why?

Ok: before commit 5a03b051ed87e72b959f32a86054e1142ac4cf55 it was
unnoticeable problem (the above two patches are fixing longstanding
bugs). But the combination of kswapd running compaction in a loop
after commit 5a03b051ed87e72b959f32a86054e1142ac4cf55, and compaction
keeping irqs disabled for too long (longstanding bug, but unnoticed
before 5a03b051ed87e72b959f32a86054e1142ac4cf55), shows both
problems. If you have a single problem you don't notice so much the
other one. But kswapd calling compaction in a loop, and compaction
keeping irqs disabled for too long are separate problems that shows
each other.

I think we want the above two patches and the patch Mel sent with
Message-ID: [ref] in 2.6.38.

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