From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756015AbaCZSzl (ORCPT ); Wed, 26 Mar 2014 14:55:41 -0400 Received: from g6t1524.atlanta.hp.com ([15.193.200.67]:23738 "EHLO g6t1524.atlanta.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751906AbaCZSzj (ORCPT ); Wed, 26 Mar 2014 14:55:39 -0400 X-Greylist: delayed 7498 seconds by postgrey-1.27 at vger.kernel.org; Wed, 26 Mar 2014 14:55:39 EDT Date: Wed, 26 Mar 2014 12:55:35 -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: <20140326185535.GE24604@oranje.fc.hp.com> References: <1390946045-2769-1-git-send-email-yinghai@kernel.org> <20140325200352.GU31785@oranje.fc.hp.com> <20140326165038.GD24604@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 Wed, Mar 26, 2014 at 10:04:52AM -0700, Yinghai Lu wrote: > On Wed, Mar 26, 2014 at 9:50 AM, Linn Crosetto wrote: > > On Tue, Mar 25, 2014 at 05:18:53PM -0700, Yinghai Lu wrote: > > > > 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 */ > > > > Do you mean some vector that is neither used by percpu_vector_irq nor > system_vector > after first_system_vector ? Yes, that is the case. In my previous example, first_system_vector is 239, but test_bit(240, used_vectors) would return unset, though it cannot be used by percpu vector_irq. If it marked all vectors unusable by percpu vector_irq, then all bits above first_system_vector would be set. > Anyway if bit is set in used_vectors, that vector can not be used by > percpu vector_irq. > > so that statement looks still right. > > Feel free to suggest right comment or changelog. The following might be more accurate: /* * The used_vectors BITMAP marks IRQs not managed by percpu vector_irq, below * first_system_vector. Vectors above first_system_vector are not managed by * percpu vector_irq. */