From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755991AbaCZQvA (ORCPT ); Wed, 26 Mar 2014 12:51:00 -0400 Received: from g2t1383g.austin.hp.com ([15.217.136.92]:54891 "EHLO g2t1383g.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755814AbaCZQu7 (ORCPT ); Wed, 26 Mar 2014 12:50:59 -0400 Date: Wed, 26 Mar 2014 10:50:38 -0600 From: Linn Crosetto To: Yinghai Lu Cc: Ingo Molnar , "H. Peter Anvin" , Thomas Gleixner , Prarit Bhargava , Linux Kernel Mailing List Subject: Re: [PATCH v3] x86, irq: get correct available vectors for cpu disable Message-ID: <20140326165038.GD24604@oranje.fc.hp.com> References: <1390946045-2769-1-git-send-email-yinghai@kernel.org> <20140325200352.GU31785@oranje.fc.hp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 25, 2014 at 05:18:53PM -0700, Yinghai Lu wrote: > On Tue, Mar 25, 2014 at 1:03 PM, Linn Crosetto wrote: > > Thanks for the patch. > > > > On Tue, Jan 28, 2014 at 01:54:05PM -0800, Yinghai Lu wrote: > >> used_vectors is a bitmap for vectors that are not tracked in per_cpu > >> vector_irq. > > > > I feel like this comment (also in the code) could be misleading because vectors > > above first_system_vector are effectively not tracked in per_cpu vector_irq, but > > also may not have the bit set in used_vectors. For example, used_vectors from a > > system that I am looking at now: > > > > first_system_vector > > 239 255 > > | | > > 10 01000 11111 11111 > > > > test_bit(240, used_vectors) does not return the correct answer to the question > > about whether the vector is tracked in per_cpu vector_irq. This leads to two > > meanings for the bitmap; for vectors less than first_system_vector whether or > > not they are tracked in per_cpu vector_irq, and for vectors above > > first_system_vector, whether or not they are in use: > > > > static inline int is_per_cpu_vector(int vector) { > > return !test_bit(vector, used_vectors) && > > vector < first_system_vector; > > } > > sorry, I can not catch what you want to say. > > Do you mean the change log or comment in the patch is not right? Just noting that not all bits above first_system_vector are set in the bitmap, so the comment in asm/desc.h and the change log could be misleading: /* used_vectors is BITMAP for irq is not managed by percpu vector_irq */ I have tested and the patch itself is good. Thanks, Linn