On 2015-08-04 21:20:20 +0530, Amit Kapila wrote:
> I have kept barriers based on comments on top of atomic read, refer
> below code:
> * No barrier semantics.
> */
> STATIC_IF_INLINE uint32
> pg_atomic_read_u32(volatile pg_atomic_uint32 *ptr)
>
> Note - The function header comments on pg_atomic_read_u32 and
> corresponding write call seems to be reversed, but that is something
> separate.
Well, the question is whether you *need* barrier semantics in that
place. If you just have a retry loop around a compare/exchange there's
no point in having one, it'll just cause needless slowdown due to
another bus-lock.
