From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753133AbeCUToQ (ORCPT ); Wed, 21 Mar 2018 15:44:16 -0400 Received: from vegas.theobroma-systems.com ([144.76.126.164]:53456 "EHLO mail.theobroma-systems.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752833AbeCUToN (ORCPT ); Wed, 21 Mar 2018 15:44:13 -0400 Subject: Re: [bug, bisected] pfifo_fast causes packet reordering To: John Fastabend , Dave Taht Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "David S. Miller" , "linux-can@vger.kernel.org" , Martin Elshuber References: <946dbe16-a2eb-eca8-8069-468859ccc78d@theobroma-systems.com> <95844480-d020-9000-53ef-0da8b965ce6e@gmail.com> <3a959e50-8656-5d9c-97b9-227d733948f8@theobroma-systems.com> <5aeb54ba-2d96-4ab5-53c4-2d3691be7acc@gmail.com> <340a6c54-6031-5522-98f5-eafdd3a37a38@theobroma-systems.com> <00cc2d41-6861-9a9c-603f-ba8013b2e2ce@theobroma-systems.com> <4e33aae4-9e87-22b4-7f09-008183ea553a@gmail.com> From: Jakob Unterwurzacher Message-ID: <983427eb-2e25-f201-c953-4cff22569deb@theobroma-systems.com> Date: Wed, 21 Mar 2018 20:44:04 +0100 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <4e33aae4-9e87-22b4-7f09-008183ea553a@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 21.03.18 19:43, John Fastabend wrote: > Thats my theory at least. Are you able to test a patch if I generate > one to fix this? Yes, no problem. I just tested with the flag change you suggested (see below, I had to keep TCQ_F_CPUSTATS to prevent a crash) and I have NOT seen OOO so far. Thanks, Jakob diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 190570f21b20..51b68ef4977b 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -792,7 +792,7 @@ struct Qdisc_ops pfifo_fast_ops __read_mostly = { .dump = pfifo_fast_dump, .change_tx_queue_len = pfifo_fast_change_tx_queue_len, .owner = THIS_MODULE, - .static_flags = TCQ_F_NOLOCK | TCQ_F_CPUSTATS, + .static_flags = TCQ_F_CPUSTATS, }; EXPORT_SYMBOL(pfifo_fast_ops);