Hi
On Fri, Feb 22, 2019 at 4:14 AM Peter Xu <pet...@redhat.com> wrote:
>
> We were pushing the context until right before running the gmainloop.
> Now since we have everything unconditionally, we can move this
> earlier.
>
> One benefit is that now it's done even before init_done_sem, so as
> long as the iothread user calls iothread_create() and completes, we
> know that the thread stack is ready.
>
This will change the default context in the iothread, for code running
there. This may not be a good idea. Until now, only sources dispatched
from iothread_get_g_main_context() would have default context
associated to it.
I don't know if the current behaviour is intentional, but it has some
logic. With this change, you may create hidden races, by changing the
default context of sources to the iothread.
> Signed-off-by: Peter Xu <pet...@redhat.com>
> ---
> iothread.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/iothread.c b/iothread.c
> index 9abdbace66..7b7cba5d04 100644
> --- a/iothread.c
> +++ b/iothread.c
> @@ -53,7 +53,7 @@ static void *iothread_run(void *opaque)
> IOThread *iothread = opaque;
>
> rcu_register_thread();
> -
> + g_main_context_push_thread_default(iothread->worker_context);
> my_iothread = iothread;
> iothread->thread_id = qemu_get_thread_id();
> qemu_sem_post(&iothread->init_done_sem);
> @@ -66,12 +66,11 @@ static void *iothread_run(void *opaque)
> * changed in previous aio_poll()
> */
> if (iothread->running && atomic_read(&iothread->run_gcontext)) {
> - g_main_context_push_thread_default(iothread->worker_context);
> g_main_loop_run(iothread->main_loop);
> - g_main_context_pop_thread_default(iothread->worker_context);
> }
> }
>
> + g_main_context_pop_thread_default(iothread->worker_context);
> rcu_unregister_thread();
> return NULL;
> }
> --
> 2.17.1
>
