Subject: Re: [PATCH 3/3] mm: Use ptep/pmdp_set_numa for updating _PAGE_NUMA bit

From: Benjamin Herrenschmidt <[email-masked]>
Date: Wed, 12 Feb 2014 05:49:30 +1100

On Tue, 2014-02-11 at 17:07 +0000, Mel Gorman wrote:
> On Tue, Feb 11, 2014 at 04:04:55PM +0530, Aneesh Kumar K.V wrote:
> > From: "Aneesh Kumar K.V" <[email-masked]>
> > 
> > Archs like ppc64 doesn't do tlb flush in set_pte/pmd functions. ppc64 also doesn't implement
> > flush_tlb_range. ppc64 require the tlb flushing to be batched within ptl locks. The reason
> > to do that is to ensure that the hash page table is in sync with linux page table.
> > We track the hpte index in linux pte and if we clear them without flushing hash and drop the
> > ptl lock, we can have another cpu update the pte and can end up with double hash. We also want
> > to keep set_pte_at simpler by not requiring them to do hash flush for performance reason.
> > Hence cannot use them while updating _PAGE_NUMA bit. Add new functions for marking pte/pmd numa
> > 
> > Signed-off-by: Aneesh Kumar K.V <[email-masked]>
> 
> Acked-by: Mel Gorman <[email-masked]>
> 

How do you guys want me to proceed ? Will you (or Andrew) send these to
Linus or should I do it myself ?

Cheers,
Ben.