Re: [RFC PATCH 0/5] Use an alternative to _PAGE_PROTNONE for _PAGE_NUMA v2

[H. Peter Anvin]

On 04/08/2014 08:22 AM, Linus Torvalds wrote:
> On Tue, Apr 8, 2014 at 7:40 AM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
>>
>> David, is your patchset going to be pushed in this merge window as expected?
> 
> Apparently aiming for 3.16 right now.
> 
>> That being said, these bits are precious, and if this ends up being a
>> case where "only Xen needs another bit" once again then Xen should
>> expect to get kicked to the curb at a moment's notice.
> 
> Quite frankly, I don't think it's a Xen-only issue. The code was hard
> to figure out even without the Xen issues. For example, nobody ever
> explained to me why it
> 
>  (a) could be the same as PROTNONE on x86
>  (b) could not be the same as PROTNONE in general
> 
> I think the best explanation for it so far was from the little voices
> in my head that sang "It's a kind of Magic", and that isn't even
> remotely the best song by Queen.
> 

Yes, I was hoping that the timing would work out so we could evict bit
10 (which *is* a Xen-only issue) and then reuse it.  I don't think the
NUMA bit is Xen-only.

	-hpa


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