Messages in this thread | | | Subject | Re: [thiscpuops upgrade 09/10] x86: this_cpu_cmpxchg and this_cpu_cmpxchg_double operations | From | Eric Dumazet <> | Date | Wed, 24 Nov 2010 01:41:41 +0100 |
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Le mardi 23 novembre 2010 à 17:51 -0600, Christoph Lameter a écrit : > pièce jointe document texte brut (this_cpu_cmpxchg_x86) > Provide support as far as the hardware capabilities of the x86 cpus > allow. > > Signed-off-by: Christoph Lameter <cl@linux.com>
> + > +#define percpu_cmpxchg16b(pcp, o1, o2, n1, n2) \ > +({ \ > + char __ret; \ > + typeof(o1) __o1 = o1; \ > + typeof(o1) __n1 = n1; \ > + typeof(o2) __o2 = o2; \ > + typeof(o2) __n2 = n2; \ > + asm("cmpxchg16b "__percpu_arg(1)"\n\tsetz %0\n\t" \ > + : "=a"(__ret), "=m" (*pcp) \ > + : "b"(__n1), "c"(__n2), "a"(__o1), "d"(__o2)); \ > + __ret; \ > +})
I thought some x86_64 cpus dont have cmpxchg16b ?
You have to check cx16 feature flag or implement a fallback ?
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