Re: [Xen-devel] [PATCH v5 1/4] VT-d PI: track the number of vcpus on pi blocking list

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 01.09.17 at 10:37, <chao.gao@xxxxxxxxx> wrote:
> it seems add_sized() won't be a LOCKed instruction.
> #define build_add_sized(name, size, type, reg) \
>     static inline void name(volatile type *addr, type val)              \
>     {                                                                   \
>         asm volatile("add" size " %1,%0"                                \
>                      : "=m" (*addr)                                     \
>                      : reg (val));                                      \
>     }

Oh, you're right. But then I'd still like you to not add a new
user, as I don't see why it was introduced in the first place:
Independent of architecture it is equivalent to

write_atomic(p, read_atomic(p) + c)

and hence I'd like to get rid of it as misleading/redundant.

Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel