From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wei Liu Subject: Re: [RFC PATCH V2] New Xen netback implementation Date: Mon, 30 Jan 2012 18:27:04 +0000 Message-ID: <1327948024.5553.43.camel@leeds.uk.xensource.com> References: <1326808024-3744-1-git-send-email-wei.liu2@citrix.com> <20120127192214.GA14437@phenom.dumpdata.com> <1327844561.2911.5.camel@leeds.uk.xensource.com> <20120129213746.GA7164@phenom.dumpdata.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: , Ian Campbell , "netdev@vger.kernel.org" , "xen-devel@lists.xensource.com" , "David Vrabel" , Paul Durrant To: Konrad Rzeszutek Wilk Return-path: Received: from smtp.ctxuk.citrix.com ([62.200.22.115]:23860 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751794Ab2A3S0x (ORCPT ); Mon, 30 Jan 2012 13:26:53 -0500 In-Reply-To: <20120129213746.GA7164@phenom.dumpdata.com> Sender: netdev-owner@vger.kernel.org List-ID: On Sun, 2012-01-29 at 21:37 +0000, Konrad Rzeszutek Wilk wrote: > > Sure. I also did some testing with limiting the amount of CPUs and found > that 'xl vcpu-set 0 N' make netback not work anymore :-( > > > > I just played with vcpu-set a bit, and I can reproduced this problem. That's a race condition. One possible fix is remove cond_resched() in the kernel thread. After removing that, it fixes the problem (at least for me). Wei. --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -994,7 +994,7 @@ int xenvif_kthread(void *data) wait_event_interruptible(vif->wq, rx_work_todo(vif) || kthread_should_stop()); - cond_resched(); + /* cond_resched(); */ if (kthread_should_stop()) break;