Am 28.10.2022 um 14:20 hat Emanuele Giuseppe Esposito geschrieben:
> Use qemu_get_current_aio_context() where possible, since we always
> submit work to the current thread anyways.
>
> We want to also be sure that the thread submitting the work is
> the same as the one processing the pool, to avoid adding
> synchronization to the pool list.
>
> Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
> Signed-off-by: Emanuele Giuseppe Esposito <eespo...@redhat.com>
> Reviewed-by: Paolo Bonzini <pbonz...@redhat.com>
> diff --git a/util/thread-pool.c b/util/thread-pool.c
> index 31113b5860..0e26687e97 100644
> --- a/util/thread-pool.c
> +++ b/util/thread-pool.c
> @@ -48,7 +48,7 @@ struct ThreadPoolElement {
> /* Access to this list is protected by lock. */
> QTAILQ_ENTRY(ThreadPoolElement) reqs;
>
> - /* Access to this list is protected by the global mutex. */
> + /* This list is only written by the thread pool's mother thread. */
> QLIST_ENTRY(ThreadPoolElement) all;
> };
>
> @@ -251,6 +251,9 @@ BlockAIOCB *thread_pool_submit_aio(ThreadPool *pool,
> {
> ThreadPoolElement *req;
>
> + /* Assert that the thread submitting work is the same running the pool */
> + assert(pool->ctx == qemu_get_current_aio_context());
> +
> req = qemu_aio_get(&thread_pool_aiocb_info, NULL, cb, opaque);
> req->func = func;
> req->arg = arg;
Why don't you drop the aio_context_acquire/release() pair in
thread_pool_completion_bh() any more now that we've added the assertion
to show that it's safe?
Kevin
