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Re: [Xen-devel] Linux/x86's _PAGE_SWP_SOFT_DIRTY definition

David Vrabel <david.vrabel@xxxxxxxxxx> wrote:
>On 21/08/13 08:42, Jan Beulich wrote:
>> All,
>> was anyone of you involved in the recent (rc5->rc6) changes here?
>> I'm asking because this new definition conflicts with _PAGE_PAT,
>> which is unused only for native Linux (and I continue to not really
>> understand their motivation to restrict themselves to just the four
>> most trivial memory types).
>I was not aware of it and that just looks broken -- not just Xen but it
>looks like it wouldn't work with (transparent) huge pages either.
>The soft dirty tracking was introduced (in 3.11-rc1) by 0f8975ec4 (mm:
>soft-dirty bits for user memory changes tracking) and the problematic
>patch adding the conflicting PTE bit is 179ef71cb (mm: save soft-dirty
>bits on swapped pages).

I am going to be in meetings most of today. David or Jan  would you be OK 
emailing the folks who came up with the patch and the committeer to mention 
that it causes a regression?  

And naturally test it first with a upstream kernel?  I presume the regressions 
is in the form of pages of WB becoming WC and suddenly applications failing 

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