From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jacek Konieczny Subject: Re: [PATCH net V2] xen-netback: don't move event pointer in TX credit timeout callback Date: Thu, 15 May 2014 15:04:36 +0200 Message-ID: <5374BB64.1080407@jajcus.net> References: <1400155158-13527-1-git-send-email-wei.liu2@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1400155158-13527-1-git-send-email-wei.liu2@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Wei Liu , xen-devel@lists.xen.org, netdev@vger.kernel.org Cc: Paul Durrant List-Id: xen-devel@lists.xenproject.org On 05/15/14 13:59, Wei Liu wrote: > ... otherwise the frontend will try to send TX event all the time, even > if no progress can be made. The pointer should only be advanced by the > routine that actually processes the ring (that is, xenvif_poll). > > Reported-by: Jacek Konieczny > Signed-off-by: Wei Liu > Acked-by: Ian Campbell > Cc: Paul Durrant > --- > drivers/net/xen-netback/netback.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c > index 7666540..8e2cbeb 100644 > --- a/drivers/net/xen-netback/netback.c > +++ b/drivers/net/xen-netback/netback.c > @@ -658,7 +658,7 @@ void xenvif_check_rx_xenvif(struct xenvif *vif) > { > int more_to_do; > > - RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do); > + more_to_do = RING_HAS_UNCONSUMED_REQUESTS(&vif->tx); > Unfortunately, this seems not enough to fix the problem I have reported here: http://lists.xenproject.org/archives/html/xen-devel/2014-05/msg01183.html The dom0 network still stalls when using rate limiting on a VIF interface after applying this patch to my 3.14.3 kernel (100% CPU#1 usage in the 'soft interrupts'). Greets, Jacek