From mboxrd@z Thu Jan 1 00:00:00 1970 From: Phil Sutter Subject: Re: [PATCH][iproute2] tc/q_htb.c: Fix the MPU value output in 'tc -d class show dev ' command Date: Wed, 16 Dec 2015 17:04:00 +0100 Message-ID: <20151216160400.GJ6555@orbit.nwl.cc> References: <5917221449918579@web5j.yandex.ru> <20151216161558.265296c7@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Dmitrii Shcherbakov , netdev@vger.kernel.org, Stephen Hemminger To: Jesper Dangaard Brouer Return-path: Received: from orbit.nwl.cc ([176.31.251.142]:36716 "EHLO mail.nwl.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751703AbbLPQEE (ORCPT ); Wed, 16 Dec 2015 11:04:04 -0500 Content-Disposition: inline In-Reply-To: <20151216161558.265296c7@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Dec 16, 2015 at 04:15:58PM +0100, Jesper Dangaard Brouer wrote: > When trying to understand this code, keep in mind that we are trying > to keep backward compatible with older kernels. Thus, this printing > might be have been left here to keep compat with older kernels, but I > think we can remove it now. For a given kernel which still uses the upper eight bits of 'mpu' as overhead value, iproute2 has become incompatible since commit bccd014b866da ("Overhead calculation is now done in the kernel.") as that eliminated the encoding while setting. So in order to stay compatible, it should have left it in place while assigning to opt.*.overhead in addition to that. Or the other way round, do the same change to the output path as well. So from a compatibility point of view, things are incompatible anyway. Nobody complained, so I'd assume there are no users requiring this (anymore). In fact, I couldn't even find the related change from using 'mpu>>8' to 'overhead' on kernel side. Dmitrii, did iproute2 without your change even print the overhead as set by you before? Looking at the code, I'd assume not. Cheers, Phil