Re: [patch v2 3/3] mm: page_alloc: fair zone allocator policy

[Stephen Rothwell]

Hi all,

On Fri, 16 Aug 2013 14:52:11 -0700 Kevin Hilman <khilman@xxxxxxxxxx> wrote:
>
> Johannes Weiner <hannes@xxxxxxxxxxx> writes:
> 
> > On Fri, Aug 16, 2013 at 10:17:01AM -0700, Kevin Hilman wrote:
> >> Johannes Weiner <hannes@xxxxxxxxxxx> writes:
> >> > On Wed, Aug 07, 2013 at 11:37:43AM -0400, Johannes Weiner wrote:
> >> > Subject: [patch] mm: page_alloc: use vmstats for fair zone allocation batching
> >> >
> >> > Avoid dirtying the same cache line with every single page allocation
> >> > by making the fair per-zone allocation batch a vmstat item, which will
> >> > turn it into batched percpu counters on SMP.
> >> >
> >> > Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
> >> 
> >> I bisected several boot failures on various ARM platform in
> >> next-20130816 down to this patch (commit 67131f9837 in linux-next.)
> >> 
> >> Simply reverting it got things booting again on top of -next.  Example
> >> boot crash below.
> >
> > Thanks for the bisect and report!
> 
> You're welcome.  Thanks for the quick fix!
> 
> > I deref the percpu pointers before initializing them properly.  It
> > didn't trigger on x86 because the percpu offset added to the pointer
> > is big enough so that it does not fall into PFN 0, but it probably
> > ended up corrupting something...
> >
> > Could you try this patch on top of linux-next instead of the revert?
> 
> Yup, that change fixes it.
> 
> Tested-by: Kevin Hilman <khilman@xxxxxxxxxx>

> Tested-by: Stephen Warren <swarren@xxxxxxxxxx>

I will add that into the akpm-current tree in linux-next today (unless
Andrew releases a new mmotm in the mean time).

-- 
Cheers,
Stephen Rothwell                    sfr@xxxxxxxxxxxxxxxx

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