From patchwork Thu May 15 14:13:22 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wei Liu X-Patchwork-Id: 349228 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 1D829140094 for ; Fri, 16 May 2014 00:13:52 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753321AbaEOONr (ORCPT ); Thu, 15 May 2014 10:13:47 -0400 Received: from smtp.citrix.com ([66.165.176.89]:61380 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751689AbaEOONq (ORCPT ); Thu, 15 May 2014 10:13:46 -0400 X-IronPort-AV: E=Sophos;i="4.97,1059,1389744000"; d="scan'208";a="131488118" Received: from accessns.citrite.net (HELO FTLPEX01CL02.citrite.net) ([10.9.154.239]) by FTLPIPO01.CITRIX.COM with ESMTP; 15 May 2014 14:13:27 +0000 Received: from ukmail1.uk.xensource.com (10.80.16.128) by smtprelay.citrix.com (10.13.107.79) with Microsoft SMTP Server id 14.3.181.6; Thu, 15 May 2014 10:13:22 -0400 Received: from zion.uk.xensource.com ([10.80.2.73]) by ukmail1.uk.xensource.com with esmtp (Exim 4.69) (envelope-from ) id 1WkwPS-0001cD-Eo; Thu, 15 May 2014 15:13:22 +0100 Date: Thu, 15 May 2014 15:13:22 +0100 From: Wei Liu To: Jacek Konieczny CC: Wei Liu , , , Paul Durrant Subject: Re: [PATCH net V2] xen-netback: don't move event pointer in TX credit timeout callback Message-ID: <20140515141322.GI1117@zion.uk.xensource.com> References: <1400155158-13527-1-git-send-email-wei.liu2@citrix.com> <5374BB64.1080407@jajcus.net> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <5374BB64.1080407@jajcus.net> User-Agent: Mutt/1.5.23 (2014-03-12) X-DLP: MIA2 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, May 15, 2014 at 03:04:36PM +0200, Jacek Konieczny wrote: > 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'). > This is a patch for 3.14.4. I've tested it myself (and looking at the right stats!) to confirm it works. ---8<--- From a4afed6c44027afff82d6fa7503faef83b01fffe Mon Sep 17 00:00:00 2001 From: Wei Liu Date: Thu, 15 May 2014 15:02:55 +0100 Subject: [PATCH] xen-netback: call napi_complete if vif is rate limited Reported-by: Jacek Konieczny Signed-off-by: Wei Liu Cc: Ian Campbell Cc: Paul Durrant Cc: David Vrabel --- drivers/net/xen-netback/common.h | 2 +- drivers/net/xen-netback/interface.c | 5 +++-- drivers/net/xen-netback/netback.c | 12 ++++++++---- 3 files changed, 12 insertions(+), 7 deletions(-) diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h index 4bf5b33..4c018de 100644 --- a/drivers/net/xen-netback/common.h +++ b/drivers/net/xen-netback/common.h @@ -219,7 +219,7 @@ void xenvif_check_rx_xenvif(struct xenvif *vif); /* Prevent the device from generating any further traffic. */ void xenvif_carrier_off(struct xenvif *vif); -int xenvif_tx_action(struct xenvif *vif, int budget); +int xenvif_tx_action(struct xenvif *vif, int budget, bool *rate_limited); int xenvif_kthread(void *data); void xenvif_kick_thread(struct xenvif *vif); diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c index 2e92d52..03cfbd6 100644 --- a/drivers/net/xen-netback/interface.c +++ b/drivers/net/xen-netback/interface.c @@ -61,6 +61,7 @@ static int xenvif_poll(struct napi_struct *napi, int budget) { struct xenvif *vif = container_of(napi, struct xenvif, napi); int work_done; + bool rate_limited; /* This vif is rogue, we pretend we've there is nothing to do * for this vif to deschedule it from NAPI. But this interface @@ -71,7 +72,7 @@ static int xenvif_poll(struct napi_struct *napi, int budget) return 0; } - work_done = xenvif_tx_action(vif, budget); + work_done = xenvif_tx_action(vif, budget, &rate_limited); if (work_done < budget) { int more_to_do = 0; @@ -96,7 +97,7 @@ static int xenvif_poll(struct napi_struct *napi, int budget) local_irq_save(flags); RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do); - if (!more_to_do) + if (!more_to_do || rate_limited) __napi_complete(napi); local_irq_restore(flags); diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index 97030c1..fa7d5da 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -1125,12 +1125,14 @@ static bool tx_credit_exceeded(struct xenvif *vif, unsigned size) return false; } -static unsigned xenvif_tx_build_gops(struct xenvif *vif, int budget) +static unsigned xenvif_tx_build_gops(struct xenvif *vif, int budget, + bool *rate_limited) { struct gnttab_copy *gop = vif->tx_copy_ops, *request_gop; struct sk_buff *skb; int ret; + *rate_limited = false; while ((nr_pending_reqs(vif) + XEN_NETBK_LEGACY_SLOTS_MAX < MAX_PENDING_REQS) && (skb_queue_len(&vif->tx_queue) < budget)) { @@ -1165,8 +1167,10 @@ static unsigned xenvif_tx_build_gops(struct xenvif *vif, int budget) /* Credit-based scheduling. */ if (txreq.size > vif->remaining_credit && - tx_credit_exceeded(vif, txreq.size)) + tx_credit_exceeded(vif, txreq.size)) { + *rate_limited = true; break; + } vif->remaining_credit -= txreq.size; @@ -1382,7 +1386,7 @@ static int xenvif_tx_submit(struct xenvif *vif) } /* Called after netfront has transmitted */ -int xenvif_tx_action(struct xenvif *vif, int budget) +int xenvif_tx_action(struct xenvif *vif, int budget, bool *rate_limited) { unsigned nr_gops; int work_done; @@ -1390,7 +1394,7 @@ int xenvif_tx_action(struct xenvif *vif, int budget) if (unlikely(!tx_work_todo(vif))) return 0; - nr_gops = xenvif_tx_build_gops(vif, budget); + nr_gops = xenvif_tx_build_gops(vif, budget, rate_limited); if (nr_gops == 0) return 0;