On Mon, Nov 02, 2015 at 10:32:54AM +0800, Fam Zheng wrote:
> On Fri, 10/30 10:07, Stefan Hajnoczi wrote:
> > On Fri, Oct 30, 2015 at 12:06:29PM +0800, Fam Zheng wrote:
> > > To comply with aio_{disable,enable}_external, we always use ppoll when
> > > aio_external_disabled() is true.
> >
> > All file descriptors are added to the epoll fd. Does that mean epoll
> > will report the same fds again after we come out of
> > ppoll()/aio_external_disabled()?
> >
> > The two constraints to think about:
> > 1. Ideally there should be no duplicated events.
> > 2. There absolutely cannot be any missed events.
> >
>
> I'm not sure I understood your question. The file descriptors added to epollfd
> are always in sync with ppoll, so there is no difference between calling
> epoll_wait and ppoll. When we come out of aio_external_disabled(), the same
> set
> of fds will be polled, but the events got by ppoll should already be handled.
>
> What am I missing?I'm asking about duplicated events. The epoll fd monitors the same set of fds as ppoll(). When we come out of aio_external_disabled() will epoll fd see the old events that have already been handled by ppoll()? Stefan
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