Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932797AbaLAXsP (ORCPT ); Mon, 1 Dec 2014 18:48:15 -0500 Received: from mail-qg0-f49.google.com ([209.85.192.49]:61317 "EHLO mail-qg0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932408AbaLAXsM (ORCPT ); Mon, 1 Dec 2014 18:48:12 -0500 MIME-Version: 1.0 In-Reply-To: <547CFD93.5000702@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> <547CFD93.5000702@linux.intel.com> From: Bjorn Helgaas Date: Mon, 1 Dec 2014 16:47:51 -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 Mon, Dec 1, 2014 at 4:45 PM, Jiang Liu wrote: > > > On 2014/12/2 2:49, Bjorn Helgaas wrote: >> 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. > Hi Bjorn, > I'm thinking of automatically turning on local vector > allocation if any host bridge has an assigned(valid) NUMA node id. > By this way, user doesn't need to specify the kernel parameter for most > cases. How about this solution? I'm not an IRQ person, but your idea sounds like figuring this out automatically, and I'm in favor of that :) >>> 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 >>> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/