Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933877Ab3E1Vaf (ORCPT ); Tue, 28 May 2013 17:30:35 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47171 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933578Ab3E1Vac (ORCPT ); Tue, 28 May 2013 17:30:32 -0400 Message-ID: <51A521DA.2080206@redhat.com> Date: Tue, 28 May 2013 17:30:02 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130514 Thunderbird/17.0.6 MIME-Version: 1.0 To: Francois Romieu CC: atomlin@redhat.com, netdev@vger.kernel.org, davem@davemloft.net, edumazet@google.com, pshelar@nicira.com, mst@redhat.com, alexander.h.duyck@intel.com, aquini@redhat.com, sergei.shtylyov@cogentembedded.com, linux-kernel@vger.kernel.org Subject: Re: [Patch v2] skbuff: Hide GFP_ATOMIC page allocation failures for dropped packets References: <1369601101-23057-1-git-send-email-atomlin@redhat.com> <20130527224149.GA4384@electric-eye.fr.zoreil.com> In-Reply-To: <20130527224149.GA4384@electric-eye.fr.zoreil.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1443 Lines: 36 On 05/27/2013 06:41 PM, Francois Romieu wrote: > atomlin@redhat.com : > [...] >> Failed GFP_ATOMIC allocations by the network stack result in dropped >> packets, which will be received on a subsequent retransmit, and an >> unnecessary, noisy warning with a kernel backtrace. >> >> These warnings are harmless, but they still cause users to panic and >> file bug reports over dropped packets. It would be better to hide the >> failed allocation warnings and backtraces, and let retransmits handle >> dropped packets quietly. > > Linux VM may be perfect but device drivers do stupid things. > > Please don't paper over it just because some shit ends in your backyard. It is impossible to free memory at the speed at which 10Gbit network packets can come in. Dropped packets are a reality. The network stack already has statistics counters to keep track of dropped packets. There is absolutely no reason to print out an entire kernel backtrace for dropped network packets. All that achieves is get people to file bug reports, which nothing can be done about. Oh, and distract them from whatever issue as causing their actual problem, and delay them fixing what was going on. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/