From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49053) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZCOi5-0006Ga-0H for qemu-devel@nongnu.org; Tue, 07 Jul 2015 04:58:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZCOi1-0004Ds-QA for qemu-devel@nongnu.org; Tue, 07 Jul 2015 04:58:36 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33243) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZCOi1-0004Dd-KY for qemu-devel@nongnu.org; Tue, 07 Jul 2015 04:58:33 -0400 Message-ID: <559B94B5.1030200@redhat.com> Date: Tue, 07 Jul 2015 16:58:29 +0800 From: Jason Wang MIME-Version: 1.0 References: <1436232067-29144-1-git-send-email-famz@redhat.com> <20150707111103-mutt-send-email-mst@redhat.com> In-Reply-To: <20150707111103-mutt-send-email-mst@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit 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: "Michael S. Tsirkin" , Fam Zheng Cc: jcmvbkbc@gmail.com, qemu-devel@nongnu.org, Stefan Hajnoczi 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? > >> --- >> >> 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