From: Andrea Arcangeli <aarcange@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Minchan Kim <minchan.kim@gmail.com>, Mel Gorman <mel@csn.ul.ie>,
Johannes Weiner <jweiner@redhat.com>,
linux-mm@kvack.org
Subject: Re: [PATCH] remove compaction from kswapd
Date: Wed, 2 Mar 2011 05:38:56 +0100 [thread overview]
Message-ID: <20110302043856.GB23911@random.random> (raw)
In-Reply-To: <20110301164143.e44e5699.akpm@linux-foundation.org>
On Tue, Mar 01, 2011 at 04:41:43PM -0800, Andrew Morton wrote:
> I'd be pretty worried about jamming this into 2.6.38 at this late
> stage. And some vague talk about something Arthur did really doesn't
> help a lot! It would be better to have some good, solid quantitative
> justification for what is really an emergency patch.
It is a emergency patch. This is zero risk, this brings back kswapd in
2.6.37 status! 2.6.38 added a new feature, I'm reverting it because
it's screwing benchmarks.
> Bear in mind that we always have a middle option: merge a patch into
> 2.6.39-rc1 and tag it for backporting into 2.6.38.x. That gives us
> more time to test it and to generally give it a shakedown. But to make
> decisions like that and to commend a patch to the -stable maintainers,
> we need to provide better information please.
This is 100% tested in 2.6.37. The new code was tested in 2.6.38-rc
and testing return -EFAIL. So we must revert this change. This patch
is doing nothing but reverting compaction-kswapd code merged in
2.6.38-rc. The old code is fully tested.
> Also, "This goes on top of the two lowlatency fixes for compaction"
> isn't particularly helpful. I need to verify that the referred-to
> patches are already in mainline but I don't have a clue what this
> description refers to. More specificity, please - it helps avoid
> mistakes.
Those two patches are fully orthogonal with this one. Andrew already
has them in -mm and there's no need to analyse those simultaneously
with this one.
I mentioned those two because those two are also important fixes to
avoid compaction to disable interrupts for too long, but they have no
actual relation to this one. One of the two fixes that Mel sent was
actually embedded into my patch but he splitted it off rightfully
because it has no relation.
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next prev parent reply other threads:[~2011-03-02 4:39 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-28 22:21 [PATCH] remove compaction from kswapd Andrea Arcangeli
2011-03-01 22:33 ` Minchan Kim
2011-03-01 22:39 ` Andrea Arcangeli
2011-03-01 23:10 ` Minchan Kim
2011-03-02 0:41 ` Andrew Morton
2011-03-02 4:38 ` Andrea Arcangeli [this message]
2011-03-02 4:39 ` Andrea Arcangeli
2011-03-02 4:53 ` Andrew Morton
2011-03-02 5:52 ` Andrea Arcangeli
2011-03-02 5:57 ` Andrew Morton
2011-03-02 17:21 ` Andrea Arcangeli
2011-03-02 14:25 ` Mel Gorman
2011-03-09 22:17 ` Andrew Morton
2011-03-09 23:50 ` Andrea Arcangeli
2011-03-10 10:11 ` Mel Gorman
2011-03-09 17:00 ` Andrea Arcangeli
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