| Message ID | 20190306115532.23025-6-peterx@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | iothread: create gcontext unconditionally | expand |
On Wed, Mar 6, 2019 at 1:05 PM Peter Xu <peterx@redhat.com> wrote: > > After consulting Paolo I know why we'd better keep the explicit > aio_poll() in iothread_run(). Document it directly into the code so > that future readers will know the answer from day one. > > Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> > --- > iothread.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/iothread.c b/iothread.c > index 045825a348..14e9f3779e 100644 > --- a/iothread.c > +++ b/iothread.c > @@ -64,6 +64,15 @@ static void *iothread_run(void *opaque) > qemu_sem_post(&iothread->init_done_sem); > > while (iothread->running) { > + /* > + * Note: from functional-wise the g_main_loop_run() below can > + * already cover the aio_poll() events, but we can't run the > + * main loop unconditionally because explicit aio_poll() here > + * is faster than g_main_loop_run() when we do not need the > + * gcontext at all (e.g., pure block layer iothreads). In > + * other words, when we want to run the gcontext with the > + * iothread we need to pay some performance for functionality. > + */ > aio_poll(iothread->ctx, true); > > /* > -- > 2.17.1 > >
diff --git a/iothread.c b/iothread.c index 045825a348..14e9f3779e 100644 --- a/iothread.c +++ b/iothread.c @@ -64,6 +64,15 @@ static void *iothread_run(void *opaque) qemu_sem_post(&iothread->init_done_sem); while (iothread->running) { + /* + * Note: from functional-wise the g_main_loop_run() below can + * already cover the aio_poll() events, but we can't run the + * main loop unconditionally because explicit aio_poll() here + * is faster than g_main_loop_run() when we do not need the + * gcontext at all (e.g., pure block layer iothreads). In + * other words, when we want to run the gcontext with the + * iothread we need to pay some performance for functionality. + */ aio_poll(iothread->ctx, true); /*
After consulting Paolo I know why we'd better keep the explicit aio_poll() in iothread_run(). Document it directly into the code so that future readers will know the answer from day one. Signed-off-by: Peter Xu <peterx@redhat.com> --- iothread.c | 9 +++++++++ 1 file changed, 9 insertions(+)