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Re: [Qemu-devel] [PATCH v2 22/23] vhost-user: wait until backend init is
From: |
Yuanhan Liu |
Subject: |
Re: [Qemu-devel] [PATCH v2 22/23] vhost-user: wait until backend init is completed |
Date: |
Thu, 30 Jun 2016 21:02:08 +0800 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Thu, Jun 30, 2016 at 05:22:43AM -0400, Marc-André Lureau wrote:
> Hi
>
> ----- Original Message -----
> > On Fri, Jun 24, 2016 at 03:51:09PM +0200, address@hidden wrote:
> > > From: Marc-André Lureau <address@hidden>
> > >
> > > The chardev waits for an initial connection before starting qemu,
> > > vhost-user wants the backend negotiation to be completed. vhost-user is
> > > started in the net_vhost_user_event callback, which is synchronously
> > > called after the socket is connected.
> > >
> > > Signed-off-by: Marc-André Lureau <address@hidden>
> > > ---
> > > net/vhost-user.c | 12 +++++++++++-
> > > 1 file changed, 11 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/net/vhost-user.c b/net/vhost-user.c
> > > index 95ed2d2..4badd9e 100644
> > > --- a/net/vhost-user.c
> > > +++ b/net/vhost-user.c
> > > @@ -24,6 +24,7 @@ typedef struct VhostUserState {
> > > VHostNetState *vhost_net;
> > > int watch;
> > > uint64_t acked_features;
> > > + bool started;
> > > } VhostUserState;
> > >
> > > typedef struct VhostUserChardevProps {
> > > @@ -211,6 +212,7 @@ static void net_vhost_user_event(void *opaque, int
> > > event)
> > > return;
> > > }
> > > qmp_set_link(name, true, &err);
> > > + s->started = true;
> > > break;
> > > case CHR_EVENT_CLOSED:
> > > qmp_set_link(name, false, &err);
> > > @@ -248,7 +250,15 @@ static int net_vhost_user_init(NetClientState *peer,
> > > const char *device,
> > > s->chr = chr;
> > > }
> > >
> > > - qemu_chr_add_handlers(chr, NULL, NULL, net_vhost_user_event,
> > > nc[0].name);
> > > + do {
> > > + Error *err = NULL;
> > > + if (qemu_chr_wait_connected(chr, &err) < 0) {
> > > + error_report_err(err);
> > > + return -1;
> > > + }
> > > + qemu_chr_add_handlers(chr, NULL, NULL,
> > > + net_vhost_user_event, nc[0].name);
> > > + } while (!s->started);
> >
> >
> > I haven't looked at your patchset carefully yet, but I did a quick test,
> > and showed that above code piece just breaks vhost-user: it's a dead loop
> > that vhost-user net will be initiated again and again.
>
> Interesting, thanks a lot for testing!
>
> The vhost-user-test works just fine, as well as vhost-user-bridge.
>
> > The dead loop is due to, we check "s->started" corresponding to last nc,
> > while we set "s->started" corresponding to the first nc.
>
> I see, that makes sense with multiqueue, I'll update the code. It would be
> really nice to have a basic multiqueue test in vhost-user-test.
My bad. It was actually my task to add the multiqueue test: it was
postponed, or even forgotten :(. If you don't mind, feel free to
add it. If you have not time for that, I will spend some time to
fix what I left.
--yliu
- [Qemu-devel] [PATCH v2 10/23] vhost: change some assert() for error_report() or silent fail, (continued)
- [Qemu-devel] [PATCH v2 10/23] vhost: change some assert() for error_report() or silent fail, marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 11/23] vhost: use error_report() instead of fprintf(stderr, ...), marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 12/23] vhost-user: check qemu_chr_fe_set_msgfds() return value, marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 16/23] Revert "vhost-net: do not crash if backend is not present", marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 14/23] qemu-char: check socket is actually connected, marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 18/23] vhost-net: success if backend has no ops->vhost_migration_done, marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 17/23] get_vhost_net() should be != null after vhost_user_init, marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 22/23] vhost-user: wait until backend init is completed, marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 20/23] char: add chr_wait_connected callback, marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 19/23] vhost: add assert() to check runtime behaviour, marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 13/23] vhost-user: check vhost_user_{read, write}() return value, marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 21/23] char: add and use tcp_chr_wait_connected, marcandre . lureau, 2016/06/24
- [Qemu-devel] [PATCH v2 23/23] tests: add /vhost-user/connect-fail test, marcandre . lureau, 2016/06/24