On Tue, Dec 01, 2015 at 01:37:37PM +0100, Paolo Bonzini wrote:
> atomic_mb_{read,set} does order accesses to the variable against
> all other accesses. In this case I'd prefer it to smp_wmb/rmb, because
> the writes to written_size are far from the writes to status.
Yes... It should be again all the other variables.
>
> Compare with thread-pool.c:
>
> req->ret = ret;
> /* Write ret before state. */
> smp_wmb();
> req->state = THREAD_DONE;
>
> /* Read state before ret. */
> smp_rmb();
>
> /* Schedule ourselves in case elem->common.cb() calls aio_poll() to
> * wait for another request that completed at the same time.
> */
> qemu_bh_schedule(pool->completion_bh);
>
> elem->common.cb(elem->common.opaque, elem->ret);
>
> It's a matter of taste though. What you wrote above is certainly okay
> as well.
Thanks for the explanation. Then I will choose smp_*() this time and
post v4 later.
Peter
>
> Paolo
