On 28/05/2015 13:49, Fam Zheng wrote: > On Thu, 05/28 13:19, Paolo Bonzini wrote: >> >> >> On 28/05/2015 13:16, Fam Zheng wrote: >>>> On 28/05/2015 03:46, Fam Zheng wrote: >>>>> The main context uses iohandler and aio_dispatch, neither calls >>>>> aio_set_dispatching(). However, if we have [2], they can be changed to >>>>> aio_poll(), then would this idea work? >>>> >>>> I think it's a bad idea to handle aio_poll for context B in a different >>>> way, just because you have an outer aio_poll for context A... >>> >>> But we already do something similar: ignoring slirp, main_loop_wait() is >>> like >>> an iothread aio_poll() without the "outermost differentiation", while the >>> current aio_poll() in bdrv_drain() is roughly "main_loop_wait() minus >>> iohandlers". >> >> Right, but the two sets of iohandlers are stored in different places, so >> it's obvious that you don't execute all of them. On the other hand, >> examining global state in aio_poll is really bad. >> > > OK. > > Would moving the ioeventfds to a new top level aio_loop_wait() be any better? > That way no global state is needed.
If we need pause/resume anyway due to block/mirror.c's use of block_job_defer_to_main_loop, I think this is not a problem anymore? Paolo
