From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53594) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZCOuK-0007Lo-La for qemu-devel@nongnu.org; Tue, 07 Jul 2015 05:11:17 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZCOuF-0001Rq-6x for qemu-devel@nongnu.org; Tue, 07 Jul 2015 05:11:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40577) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZCOuE-0001RE-OM for qemu-devel@nongnu.org; Tue, 07 Jul 2015 05:11:11 -0400 Date: Tue, 7 Jul 2015 12:10:15 +0300 From: "Michael S. Tsirkin" Message-ID: <20150707120807-mutt-send-email-mst@redhat.com> References: <1436232067-29144-1-git-send-email-famz@redhat.com> <20150707111103-mutt-send-email-mst@redhat.com> <559B94B5.1030200@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <559B94B5.1030200@redhat.com> Subject: Re: [Qemu-devel] [PATCH v2] net: Flush queued packets when guest resumes List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jason Wang Cc: jcmvbkbc@gmail.com, Fam Zheng , qemu-devel@nongnu.org, Stefan Hajnoczi On Tue, Jul 07, 2015 at 04:58:29PM +0800, Jason Wang wrote: > > > On 07/07/2015 04:13 PM, Michael S. Tsirkin wrote: > > On Tue, Jul 07, 2015 at 09:21:07AM +0800, Fam Zheng wrote: > >> Since commit 6e99c63 "net/socket: Drop net_socket_can_send" and friends, > >> net queues need to be explicitly flushed after qemu_can_send_packet() > >> returns false, because the netdev side will disable the polling of fd. > >> > >> This fixes the case of "cont" after "stop" (or migration). > >> > >> Signed-off-by: Fam Zheng > > Note virtio has its own handler which must be used to > > flush packets - this one might run too early or too late. > > If runs too realy (DRIVER_OK is not set), then: packet will be dropped > (if this patch is used with "drop virtio_net_can_receive()", or the > queue will be purged since qemu_can_send_packet() returns false. If too > late, at least tap read poll will be enabled. So still looks ok? It's still not helpful for virtio. So which cards are fixed? I just find the comment This fixes the case of "cont" after "stop" (or migration) too vague. Can you please include the info about what's broken in the commit log? > > > >> --- > >> > >> v2: Unify with VM stop handler. (Stefan) > >> --- > >> net/net.c | 19 ++++++++++++------- > >> 1 file changed, 12 insertions(+), 7 deletions(-) > >> > >> diff --git a/net/net.c b/net/net.c > >> index 6ff7fec..28a5597 100644 > >> --- a/net/net.c > >> +++ b/net/net.c > >> @@ -1257,14 +1257,19 @@ void qmp_set_link(const char *name, bool up, Error **errp) > >> static void net_vm_change_state_handler(void *opaque, int running, > >> RunState state) > >> { > >> - /* Complete all queued packets, to guarantee we don't modify > >> - * state later when VM is not running. > >> - */ > >> - if (!running) { > >> - NetClientState *nc; > >> - NetClientState *tmp; > >> + NetClientState *nc; > >> + NetClientState *tmp; > >> > >> - QTAILQ_FOREACH_SAFE(nc, &net_clients, next, tmp) { > >> + QTAILQ_FOREACH_SAFE(nc, &net_clients, next, tmp) { > >> + if (running) { > >> + /* Flush queued packets and wake up backends. */ > >> + if (nc->peer && qemu_can_send_packet(nc)) { > >> + qemu_flush_queued_packets(nc->peer); > >> + } > >> + } else { > >> + /* Complete all queued packets, to guarantee we don't modify > >> + * state later when VM is not running. > >> + */ > >> qemu_flush_or_purge_queued_packets(nc, true); > >> } > >> } > >> -- > >> 2.4.3