From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932168Ab0LIV4m (ORCPT ); Thu, 9 Dec 2010 16:56:42 -0500 Received: from www.tglx.de ([62.245.132.106]:56606 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932071Ab0LIV4e (ORCPT ); Thu, 9 Dec 2010 16:56:34 -0500 Date: Thu, 9 Dec 2010 22:56:13 +0100 (CET) From: Thomas Gleixner To: Tejun Heo cc: linux-kernel@vger.kernel.org, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, eric.dumazet@gmail.com, yinghai@kernel.org, brgerst@gmail.com, gorcunov@gmail.com, penberg@kernel.org Subject: Re: [PATCH UPDATED#3 04/16] x86: setup_local_APIC() must always be called with preemption disabled In-Reply-To: <4D00B3B9.7060702@kernel.org> Message-ID: References: <1290871325-3055-1-git-send-email-tj@kernel.org> <1290871325-3055-5-git-send-email-tj@kernel.org> <4D00B3B9.7060702@kernel.org> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 9 Dec 2010, Tejun Heo wrote: > setup_local_APIC() is used to setup local APIC early during CPU > initialization and already assumes that preemption is disabled on > entry. However, The function unnecessarily disables and enables > preemption and uses smp_processor_id() multiple times in and out of > the nested preemption disabled section. This gives the wrong > impression that the function might be able to handle being called with > preemption enabled and/or migrated to another processor in the middle. > > Make it clear that the function is always called with preemption > disabled, drop the confusing preemption disable block and call > smp_processor_id() once at the beginning of the function. AFAICT, this one is completely unrelated to that NUMA cleanup, right ? So this can be applied independent and should never have been part of that NUMA series in the first place. Thanks, tglx