From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757958Ab2IDW6z (ORCPT ); Tue, 4 Sep 2012 18:58:55 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42695 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757871Ab2IDW6y (ORCPT ); Tue, 4 Sep 2012 18:58:54 -0400 Message-ID: <50468778.5000207@redhat.com> Date: Tue, 04 Sep 2012 23:58:00 +0100 From: Pedro Alves User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120828 Thunderbird/15.0 MIME-Version: 1.0 To: Steven Rostedt CC: Mathieu Desnoyers , Sasha Levin , Tejun Heo , torvalds@linux-foundation.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, paul.gortmaker@windriver.com, davem@davemloft.net, mingo@elte.hu, ebiederm@xmission.com, aarcange@redhat.com, ericvh@gmail.com, netdev@vger.kernel.org, josh@joshtriplett.org, eric.dumazet@gmail.com, axboe@kernel.dk, agk@redhat.com, dm-devel@redhat.com, neilb@suse.de, ccaulfie@redhat.com, teigland@redhat.com, Trond.Myklebust@netapp.com, bfields@fieldses.org, fweisbec@gmail.com, jesse@nicira.com, venkat.x.venkatsubra@oracle.com, ejt@redhat.com, snitzer@redhat.com, edumazet@google.com, linux-nfs@vger.kernel.org, dev@openvswitch.org, rds-devel@oss.oracle.com, lw@cn.fujitsu.com Subject: Re: [PATCH v3 01/17] hashtable: introduce a small and naive hashtable References: <20120824203332.GF21325@google.com> <5037E9D9.9000605@gmail.com> <20120824212348.GK21325@google.com> <5038074D.300@gmail.com> <20120824230740.GN21325@google.com> <20120825042419.GA27240@Krystal> <503C95E4.3010000@gmail.com> <20120828101148.GA21683@Krystal> <503CAB1E.5010408@gmail.com> <20120828115638.GC23818@Krystal> <20120828230050.GA3337@Krystal> <1346772948.27919.9.camel@gandalf.local.home> <50462C99.5000007@redhat.com> <50462EE8.1090903@redhat.com> <1346779027.27919.15.camel@gandalf.local.home> <50463883.8080706@redhat.com> <1346792345.27919.18.camel@gandalf.local.home> <504677C8.3050801@redhat.com> <1346798509.27919.25.camel@gandalf.local.home> In-Reply-To: <1346798509.27919.25.camel@gandalf.local.home> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/04/2012 11:41 PM, Steven Rostedt wrote: > Ah, I missed the condition with the rec == &pg->records[pg->index]. But > if ftrace_pages_start is NULL, the rec = &pg->records[pg->index] will > fault. Right. > > You could do something like rec = pg ? &pg->records[pg->index] : NULL, Right. > but IIRC, the comma operator does not guarantee order evaluation. That > is, the compiler is allowed to process "a , b" as "b; a;" and not "a; > b;". Not true. The comma operator introduces a sequence point. It's the comma that separates function parameters that doesn't guarantee ordering. -- Pedro Alves