From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH] pkt_sched: QFQ Plus: fair-queueing service at DRR cost Date: Tue, 20 Nov 2012 13:15:16 -0500 (EST) Message-ID: <20121120.131516.311189144173456123.davem@davemloft.net> References: <20121120095304.420ded7c@nehalam.linuxnetplumber.net> <20121120.130202.1918742054229219388.davem@davemloft.net> <20121120100958.010e7605@nehalam.linuxnetplumber.net> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: paolo.valente@unimore.it, jhs@mojatatu.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, rizzo@iet.unipi.it, fchecconi@gmail.com To: shemminger@vyatta.com Return-path: In-Reply-To: <20121120100958.010e7605@nehalam.linuxnetplumber.net> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org From: Stephen Hemminger Date: Tue, 20 Nov 2012 10:09:58 -0800 > On Tue, 20 Nov 2012 13:02:02 -0500 (EST) > David Miller wrote: > >> From: Stephen Hemminger >> Date: Tue, 20 Nov 2012 09:53:04 -0800 >> >> > There are actually lots of bogus warnings than seem to only occur >> > because gcc 4.4 does a bad job of checking. Later versions are fixed >> > and don't generate warnings. >> > >> > My preference is to not add the unnecessary initialization because >> > if you get in the habit of doing it. The whole purpose of the uninitialized >> > check is lost. >> >> Try again, this was with gcc-4.7.2-2 on Fedora. >> >> There are too many preconditions, across multiple basic block, which >> together ensure the skb is in fact initialized at the point in >> question and the compiler simply isn't sophisticated enough to see >> that. > > Weird, it compiles clean on x86-84 on Debian. > gcc-4.7.real (Debian 4.7.2-4) 4.7.2 Fedora backports a lot more stuff into gcc than Debian does.