From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756396AbZGBVtQ (ORCPT ); Thu, 2 Jul 2009 17:49:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754020AbZGBVtD (ORCPT ); Thu, 2 Jul 2009 17:49:03 -0400 Received: from hqemgate04.nvidia.com ([216.228.112.152]:6823 "EHLO hqemgate04.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753456AbZGBVtC (ORCPT ); Thu, 2 Jul 2009 17:49:02 -0400 X-Greylist: delayed 302 seconds by postgrey-1.27 at vger.kernel.org; Thu, 02 Jul 2009 17:49:02 EDT X-PGP-Universal: processed; by hqnvupgp04.nvidia.com on Thu, 02 Jul 2009 14:43:55 -0700 Message-ID: <4A4CDCA4.3040505@nvidia.com> Date: Thu, 02 Jul 2009 12:13:24 -0400 From: Ayaz Abdulla User-Agent: Mozilla Thunderbird 1.0.2-6 (X11/20050513) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Eric Dumazet CC: Ingo Molnar , David Miller , "torvalds@linux-foundation.org" , "akpm@linux-foundation.org" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [GIT]: Networking References: <20090630.213927.180401151.davem@davemloft.net> <20090702075724.GA10608@elte.hu> <4A4C9125.8020705@gmail.com> <4A4CBE7D.2060603@gmail.com> In-Reply-To: <4A4CBE7D.2060603@gmail.com> X-NVConfidentiality: public Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-OriginalArrivalTime: 02 Jul 2009 21:43:56.0034 (UTC) FILETIME=[33252620:01C9FB5E] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Eric Dumazet wrote: > Eric Dumazet a écrit : > >>Ingo Molnar a écrit : >> >>>>The following changes since commit 52989765629e7d182b4f146050ebba0abf2cb0b7: >>>> Linus Torvalds (1): >>>> Merge git://git.kernel.org/.../davem/net-2.6 >>>> >>>>are available in the git repository at: >>>> >>>> master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6.git master >>> >>>Hm, something in this lot quickly wrecked networking here - see the >>>tx timeout dump below. It starts with: >>> >>>[ 351.004596] WARNING: at net/sched/sch_generic.c:246 dev_watchdog+0x10b/0x19c() >>>[ 351.011815] Hardware name: System Product Name >>>[ 351.016220] NETDEV WATCHDOG: eth0 (forcedeth): transmit queue 0 timed out >>> >>>Config attached. Unfortunately i've got no time to do bisection >>>today. >> >> >> >>forcedeth might have a problem, in its netif_wake_queue() logic, but >>I could not see why a recent patch could make this problem visible now. >> >>CPU0/1: AMD Athlon(tm) 64 X2 Dual Core Processor 3800+ stepping 02 >>is not a new cpu either :) >> >>forcedeth uses an internal tx_stop without appropriate barrier. >> >>Could you try following patch ? >> >>(random guess as I dont have much time right now) > > > Oh well this patch was soooo stupid, sorry Ingo. > > > We might have a race in napi_schedule(), leaving interrupts disabled forever. > I cannot test this patch, I dont have the hardware... > > Thanks > > diff --git a/drivers/net/forcedeth.c b/drivers/net/forcedeth.c > index 1094d29..3b4e076 100644 > --- a/drivers/net/forcedeth.c > +++ b/drivers/net/forcedeth.c > @@ -3514,11 +3514,13 @@ static irqreturn_t nv_nic_irq(int foo, void *data) > nv_msi_workaround(np); > > #ifdef CONFIG_FORCEDETH_NAPI > - napi_schedule(&np->napi); > - > - /* Disable furthur irq's > - (msix not enabled with napi) */ > - writel(0, base + NvRegIrqMask); > + if (napi_schedule_prep(&np->napi)) { > + /* > + * Disable further irq's (msix not enabled with napi) > + */ > + writel(0, base + NvRegIrqMask); > + __napi_schedule(&np->napi); > + } Yes, good catch. There is a race condition here with napi poll. I would prefer to do the following to keep the code simple and clean. writel(0, base + NvRegIrqMask); napi_schedule(&np->napi); ..... > > #else > do > @@ -3615,12 +3617,13 @@ static irqreturn_t nv_nic_irq_optimized(int foo, void *data) > nv_msi_workaround(np); > > #ifdef CONFIG_FORCEDETH_NAPI > - napi_schedule(&np->napi); > - > - /* Disable furthur irq's > - (msix not enabled with napi) */ > - writel(0, base + NvRegIrqMask); > - > + if (napi_schedule_prep(&np->napi)) { > + /* > + * Disable further irq's (msix not enabled with napi) > + */ > + writel(0, base + NvRegIrqMask); > + __napi_schedule(&np->napi); > + } > #else > do > {