On Wed, 22 Apr 2020 08:29:39 +0000 "Zhang, Chen" <chen.zh...@intel.com> wrote:
> > -----Original Message-----
> > From: Lukas Straub <lukasstra...@web.de>
> > Sent: Thursday, April 9, 2020 2:34 AM
> > To: qemu-devel <qemu-devel@nongnu.org>
> > Cc: Zhang, Chen <chen.zh...@intel.com>; Li Zhijian
> > <lizhij...@cn.fujitsu.com>; Jason Wang <jasow...@redhat.com>; Marc-
> > André Lureau <marcandre.lur...@redhat.com>; Paolo Bonzini
> > <pbonz...@redhat.com>
> > Subject: [PATCH 1/3] net/colo-compare.c: Create event_bh with the right
> > AioContext
> >
> > qemu_bh_new will set the bh to be executed in the main loop. This causes
> > problems as colo_compare_handle_event assumes that it has exclusive
> > access the queues, which are also accessed in the iothread. It also assumes
> > that it runs in a different thread than the caller and takes the appropriate
> > locks.
> >
> > Create the bh with the AioContext of the iothread to fulfill these
> > assumptions.
> >
>
> Looks good for me, I assume it will increase performance. Do you have related
> data?
No, this fixes several crashes because the queues where accessed concurrently
from
multiple threads. Sorry for my bad wording.
Regards,
Lukas Straub
> Thanks
> Zhang Chen
>
> > Signed-off-by: Lukas Straub <lukasstra...@web.de>
> > ---
> > net/colo-compare.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/net/colo-compare.c b/net/colo-compare.c index
> > 10c0239f9d..1de4220fe2 100644
> > --- a/net/colo-compare.c
> > +++ b/net/colo-compare.c
> > @@ -890,6 +890,7 @@ static void colo_compare_handle_event(void
> > *opaque)
> >
> > static void colo_compare_iothread(CompareState *s) {
> > + AioContext *ctx = iothread_get_aio_context(s->iothread);
> > object_ref(OBJECT(s->iothread));
> > s->worker_context = iothread_get_g_main_context(s->iothread);
> >
> > @@ -906,7 +907,7 @@ static void colo_compare_iothread(CompareState *s)
> > }
> >
> > colo_compare_timer_init(s);
> > - s->event_bh = qemu_bh_new(colo_compare_handle_event, s);
> > + s->event_bh = aio_bh_new(ctx, colo_compare_handle_event, s);
> > }
> >
> > static char *compare_get_pri_indev(Object *obj, Error **errp)
> > --
> > 2.20.1
>
pgpeamQKggJZK.pgp
Description: OpenPGP digital signature
