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SubjectRe: Linux 2.6.32-rc1

* Ingo Molnar <mingo@elte.hu> wrote:

> * Linus Torvalds <torvalds@linux-foundation.org> wrote:
>
> > On Wed, 30 Sep 2009, Eric Dumazet wrote:
> > > > +#define cmpxchg64(ptr, o, n) \
> > > > +({ \
> > > > + __typeof__(*(ptr)) __ret; \
> > > > + __typeof__(*(ptr)) __old = (o); \
> > > > + __typeof__(*(ptr)) __new = (n); \
> > > > + alternative_io("call cmpxchg8b_emu", \
> > > > + "lock; cmpxchg8b (%%esi)" , \
> > > > + X86_FEATURE_CX8, \
> > > > + "=A" (__ret), \
> > > > + "S" ((ptr)), "0" (__old), \
> > > > + "b" ((unsigned int)__new), \
> > > > + "c" ((unsigned int)(__new>>32))); \
> > >
> > > probably a "memory" clobber is needed, alternative_io() doesnt provide it.
> >
> > Yeah, good catch.
>
> Yeah - i'm testing this right now, it looks like something that could
> explain the hang.

Yeah - that was the cause of the hang.

I've pushed out the updated patches - they should show up in this thread
soon. I also updated the emulation implementation to your simpler
variant. (will test that too)

Ingo


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