Re: kswapd craziness in 3.7

[Andrew Morton]

On Wed, 28 Nov 2012 23:54:12 +0000
Mel Gorman <mgorman@xxxxxxx> wrote:

> On Wed, Nov 28, 2012 at 02:52:15PM -0800, Andrew Morton wrote:
> > On Wed, 28 Nov 2012 10:13:59 +0000
> > Mel Gorman <mgorman@xxxxxxx> wrote:
> > 
> > > Based on the reports I've seen I expect the following to work for 3.7
> > > 
> > > Keep
> > >   96710098 mm: revert "mm: vmscan: scale number of pages reclaimed by reclaim/compaction based on failures"
> > >   ef6c5be6 fix incorrect NR_FREE_PAGES accounting (appears like memory leak)
> > > 
> > > Revert
> > >   82b212f4 Revert "mm: remove __GFP_NO_KSWAPD"
> > > 
> > > Merge
> > >   mm: vmscan: fix kswapd endless loop on higher order allocation
> > >   mm: Avoid waking kswapd for THP allocations when compaction is deferred or contended
> > 
> > "mm: Avoid waking kswapd for THP ..." is marked "I have not tested it
> > myself" and when Zdenek tested it he hit an unexplained oom.
> > 
> 
> I thought Zdenek was testing with __GFP_NO_KSWAPD when he hit that OOM.
> Further, when he hit that OOM, it looked like a genuine OOM. He had no
> swap configured and inactive/active file pages were very low. Finally,
> the free pages for Normal looked off and could also have been affected by
> the accounting bug. I'm looking at https://lkml.org/lkml/2012/11/18/132
> here. Are you thinking of something else?

who, me, think?  I was trying to work out why I hadn't merged or queued
a patch which you felt was important.  Turned out it was because it
didn't look very tested and final.

> I have not tested with the patch admittedly but Thorsten has and seemed
> to be ok with it https://lkml.org/lkml/2012/11/23/276.

OK, I'll queue revert-revert-mm-remove-__gfp_no_kswapd.patch and the
patch from https://patchwork.kernel.org/patch/1728081/.

So what I'm currently sitting on for 3.7 is

mm-compaction-fix-return-value-of-capture_free_page.patch
mm-vmemmap-fix-wrong-use-of-virt_to_page.patch
mm-vmscan-fix-endless-loop-in-kswapd-balancing.patch
revert-revert-mm-remove-__gfp_no_kswapd.patch
mm-avoid-waking-kswapd-for-thp-allocations-when-compaction-is-deferred-or-contended.patch
mm-soft-offline-split-thp-at-the-beginning-of-soft_offline_page.patch

> > Please identify "Johannes' patch"?
> 
> mm: vmscan: fix kswapd endless loop on higher order allocation

OK, we have that.  I'll start a round of testing, do another -next drop
and send the above Linuswards tomorrow.

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