On Wed, 03/25 12:25, Paolo Bonzini wrote: > > > On 25/03/2015 09:31, Fam Zheng wrote: > > I was looking at block jobs' AioContext and realized that the block job > > coroutines are actually started in main loop. > > > > I'm confused because 5a7e7a0bad17c96e03f55ed7019e2d7545e21a96 and friends in > > the series [1] seem to move the coroutines to the BDS's iothreads, but it > > didn't do that. > > > > (Although after the first block_job_yield or sleep, the coroutines ARE > > resumed > > in the right AioContext.) > > > > Why is it safe to start the jobs from the main thread where QMP command is > > handled? I see no guarantee that the jobs won't access BDS before first > > yield > > but after releasing the AioContext. > > > > Is this a bug? > > It's okay because the coroutine is started while the main thread is > holding the AioContext. So the first "stint" of the coroutine, until > the first yield, is done in the main thread but still with the > AioContext held.
I see! That's what I missed. Thanks! Fam > > After the first yield, the main thread releases the AioContext, the > dataplane thread gets it back and the coroutine is moved to the > dataplane thread. >
