From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40942) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bIbbm-0001Mx-6x for qemu-devel@nongnu.org; Thu, 30 Jun 2016 09:02:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bIbbi-0001i8-0W for qemu-devel@nongnu.org; Thu, 30 Jun 2016 09:02:17 -0400 Received: from mga09.intel.com ([134.134.136.24]:16019) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bIbbh-0001hy-R9 for qemu-devel@nongnu.org; Thu, 30 Jun 2016 09:02:13 -0400 Date: Thu, 30 Jun 2016 21:02:08 +0800 From: Yuanhan Liu Message-ID: <20160630130208.GI2831@yliu-dev.sh.intel.com> References: <20160624135110.17260-1-marcandre.lureau@redhat.com> <20160624135110.17260-23-marcandre.lureau@redhat.com> <20160630063833.GG2831@yliu-dev.sh.intel.com> <820501303.1010048.1467278563588.JavaMail.zimbra@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <820501303.1010048.1467278563588.JavaMail.zimbra@redhat.com> Subject: Re: [Qemu-devel] [PATCH v2 22/23] vhost-user: wait until backend init is completed List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?iso-8859-1?Q?Marc-Andr=E9?= Lureau Cc: marcandre lureau , qemu-devel@nongnu.org, mukawa@igel.co.jp, victork@redhat.com, jonshin@cisco.com, mst@redhat.com 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, marcandre.lureau@redhat.com wrote: > > > From: Marc-André Lureau > > > > > > 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 > > > --- > > > 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