Re: [Xen-devel] [PATCH 00/10] [PATCH RFC V2] Paravirtualized ticketlocks

[Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>]

On Wed, Sep 28, 2011 at 8:55 AM, Jan Beulich <JBeulich@xxxxxxxx> wrote:
>
>> just use "lock xaddw" there too.
>
> I'm afraid that's not possible, as that might carry from the low 8 bits
> into the upper 8 ones, which must be avoided.

Oh damn, you're right. So I guess the "right" way to do things is with
cmpxchg, but some nasty mfence setup could do it too.

                          Linus

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