From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756765AbaBFTM6 (ORCPT ); Thu, 6 Feb 2014 14:12:58 -0500 Received: from mx1.redhat.com ([209.132.183.28]:20112 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751956AbaBFTMx (ORCPT ); Thu, 6 Feb 2014 14:12:53 -0500 Message-ID: <52F3DEA4.5090806@redhat.com> Date: Thu, 06 Feb 2014 14:12:36 -0500 From: Prarit Bhargava User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110419 Red Hat/3.1.10-1.el6_0 Thunderbird/3.1.10 MIME-Version: 1.0 To: Yinghai Lu CC: Ingo Molnar , "H. Peter Anvin" , Thomas Gleixner , linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] x86, irq: get correct available vectors for cpu disable References: <1390946045-2769-1-git-send-email-yinghai@kernel.org> In-Reply-To: <1390946045-2769-1-git-send-email-yinghai@kernel.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/28/2014 04:54 PM, Yinghai Lu wrote: > used_vectors is a bitmap for vectors that are not tracked in per_cpu > vector_irq. > used_vectors contains information on the first 32 exceptions, the system vectors. > the IA32_SYSCALL_VECTOR (0x80), and the IRQ_MOVE_CLEANUP_VECTOR (0x20). > > assign_irq_vectors() assigns vectors up to first_system_vector and > it will not use vectors that are set used_vectors. > > This patch modifies the code to scan up to first_system_vector > and do a test on the used_vectors bitmap. > > So count avaiable vectors correctly. > > -v2: fix compiling problem. > -v3: update changelog and commets > > Signed-off-by: Yinghai Lu > > --- > arch/x86/kernel/irq.c | 18 ++++++++++++++++-- > 1 file changed, 16 insertions(+), 2 deletions(-) > > Index: linux-2.6/arch/x86/kernel/irq.c > =================================================================== > --- linux-2.6.orig/arch/x86/kernel/irq.c > +++ linux-2.6/arch/x86/kernel/irq.c > @@ -17,6 +17,7 @@ > #include > #include > #include > +#include > > #define CREATE_TRACE_POINTS > #include > @@ -321,8 +322,21 @@ int check_irq_vectors_for_cpu_disable(vo > for_each_online_cpu(cpu) { > if (cpu == this_cpu) > continue; > - for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; > - vector++) { > + > + /* > + * assign_irq_vector() only scan per_cpu vectors from > + * FIRST_EXTERNAL_VECTOR to first_system_vector. > + * It aslo skip vectors that are set in used_vectors bitmask. "also" ... but not a big deal IMO. Reviewed-by: Prarit Bhargava Tested-by: Prarit Bhargava P. > + * used_vectors could have bits set for > + * IA32_SYSCALL_VECTOR (0x80) > + * IRQ_MOVE_CLEANUP_VECTOR (0x20) > + * Don't count those as available vectors. > + */ > + for (vector = FIRST_EXTERNAL_VECTOR; > + vector < first_system_vector; vector++) { > + if (test_bit(vector, used_vectors)) > + continue; > + > if (per_cpu(vector_irq, cpu)[vector] < 0) > count++; > }