From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932132AbaLAStf (ORCPT ); Mon, 1 Dec 2014 13:49:35 -0500 Received: from mail-qa0-f45.google.com ([209.85.216.45]:63011 "EHLO mail-qa0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753934AbaLAStc (ORCPT ); Mon, 1 Dec 2014 13:49:32 -0500 MIME-Version: 1.0 In-Reply-To: <1416901802-24211-39-git-send-email-jiang.liu@linux.intel.com> References: <1416901802-24211-1-git-send-email-jiang.liu@linux.intel.com> <1416901802-24211-39-git-send-email-jiang.liu@linux.intel.com> From: Bjorn Helgaas Date: Mon, 1 Dec 2014 11:49:11 -0700 Message-ID: Subject: Re: [Patch Part3 v4 38/38] x86, irq: Add kernel parameter vector_alloc to set CPU vector allocation policy To: Jiang Liu Cc: Benjamin Herrenschmidt , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , "Rafael J. Wysocki" , Randy Dunlap , Yinghai Lu , Borislav Petkov , Jonathan Corbet , "x86@kernel.org" , Konrad Rzeszutek Wilk , Andrew Morton , Tony Luck , Joerg Roedel , Greg Kroah-Hartman , "linux-kernel@vger.kernel.org" , "linux-pci@vger.kernel.org" , "linux-acpi@vger.kernel.org" , Daniel J Blueman , "linux-doc@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 25, 2014 at 12:50 AM, Jiang Liu wrote: > Parameter vector_alloc should be set to an integer with: > bit 0: enable allocating CPU vector from CPUs on device local node. > That's to allocate from cpumask_of_node(irq_data->node). > bit 1: enable the default policy, which is to allocate from > apic->target_cpus(). > > When allocating vectors, it tries all enabled policies from lower bit > position to higher bit position. > > This option could be use to optimize interrupt distribution on large > system such as NumaChip etc. Why can't we figure this out automatically? Having a kernel parameter is a pain in the neck for users. > Signed-off-by: Jiang Liu > Cc: Daniel J Blueman > --- > Documentation/kernel-parameters.txt | 6 ++++++ > arch/x86/kernel/apic/vector.c | 11 +++++++++++ > 2 files changed, 17 insertions(+) > > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt > index 4c81a860cc2b..a175c5016954 100644 > --- a/Documentation/kernel-parameters.txt > +++ b/Documentation/kernel-parameters.txt > @@ -3709,6 +3709,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted. > vector= [IA-64,SMP] > vector=percpu: enable percpu vector domain > > + vector_alloc= [x86,SMP] > + vector_alloc=policy: policy is a bitmap, bit 0 > + for allocating CPU vector from CPUs on device local > + node; bit 1 for the default policy to allocating from > + apic->target_cpus(). All higher bits are reserved. > + > video= [FB] Frame buffer configuration > See Documentation/fb/modedb.txt. > > diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c > index 16de8906ee1e..1158843551c7 100644 > --- a/arch/x86/kernel/apic/vector.c > +++ b/arch/x86/kernel/apic/vector.c > @@ -79,6 +79,17 @@ void set_vector_alloc_policy(unsigned int policy) > x86_vector_alloc_policy = policy | X86_VECTOR_POL_CALLER; > } > > +static int __init apic_parse_vector_policy(char *str) > +{ > + int policy; > + > + if (get_option(&str, &policy) == 1) > + set_vector_alloc_policy(policy); > + > + return 1; > +} > +__setup("vector_alloc=", apic_parse_vector_policy); > + > static struct apic_chip_data *alloc_apic_chip_data(int node) > { > struct apic_chip_data *data; > -- > 1.7.10.4 >