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

[Kevin Hilman <khilman@linaro.org>]

Johannes Weiner <hannes@cmpxchg.org> writes:

> Hi Kevin,
>
> On Fri, Aug 16, 2013 at 10:17:01AM -0700, Kevin Hilman wrote:
>> Johannes Weiner <hannes@cmpxchg.org> 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@cmpxchg.org>
>> 
>> 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@linaro.org>

Kevin

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