On Thu, Dec 05, 2024 at 06:50:23PM -0300, Fabiano Rosas wrote:
> I think I remember now, what's needed is to release p->sem and wait on
> p->sem_sync (one in each of these loops). We don't need to set the
> pending_sync flag if it's not going to be used:
>
> multifd_send_sync_main:
> for () {
> ...
> if (remote_sync) {
> assert(qatomic_read(&p->pending_sync) == false);
> qatomic_set(&p->pending_sync, true);
> }
> qemu_sem_post(&p->sem);
> }
> for () {
> ...
> qemu_sem_wait(&multifd_send_state->channels_ready);
> qemu_sem_wait(&p->sem_sync);
> }
>
> in multifd_send_thread:
>
> if (qatomic_load_acquire(&p->pending_job)) {
> ...
> qatomic_store_release(&p->pending_job, false);
> } else if (qatomic_read(&p->pending_sync)) {
> ...
> p->flags = MULTIFD_FLAG_SYNC;
> qatomic_set(&p->pending_sync, false);
> qemu_sem_post(&p->sem_sync);
> } else {
How do you trigger this "else" path at all, if without setting pending_sync
first?
> qemu_sem_post(&p->sem_sync);
> }
>
> Is this clearer? Then we avoid the enum altogether, a boolean would
> suffice.
So one of us missed something. :)
In case if I missed it, a runnable patch would work to clarify.
--
Peter Xu
