| Date | Fri, 26 Nov 2010 17:51:15 +0100 | From | Tejun Heo <> | Subject | Re: [thiscpuops upgrade 08/10] percpu: generic this_cpu_cmpxchg() and this_cpu_cmpxchg_double support |
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On 11/24/2010 12:51 AM, Christoph Lameter wrote: > +/* > + * cmpxchg_double replaces two adjacent scalars at once. The first parameter > + * passed is a percpu pointer, not a scalar like the other this_cpu > + * operations. This is so because the function operates on two scalars > + * (must be of same size). A truth value is returned to indicate success or > + * failure (since a double register result is difficult to handle). > + * There is very limited hardware support for these operations. So only certain > + * sizes may work. > + */ > +#define __this_cpu_generic_cmpxchg_double(pcp, oval1, oval2, nval1, nval2) \
Ah... this is scary. If it proves to be useful enough, sure, but otherwise I'd like to avoid it.
Thanks.
-- tejun
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