From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B4E4CECDFB8 for ; Wed, 18 Jul 2018 08:09:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5E2F52075A for ; Wed, 18 Jul 2018 08:09:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5E2F52075A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729185AbeGRIqU (ORCPT ); Wed, 18 Jul 2018 04:46:20 -0400 Received: from foss.arm.com ([217.140.101.70]:57122 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726282AbeGRIqU (ORCPT ); Wed, 18 Jul 2018 04:46:20 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 398D47A9; Wed, 18 Jul 2018 01:09:39 -0700 (PDT) Received: from [10.1.207.53] (e112298-lin.cambridge.arm.com [10.1.207.53]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 234673F589; Wed, 18 Jul 2018 01:09:37 -0700 (PDT) Subject: Re: [RFC PATCH 1/4] genirq: Provide basic NMI management for interrupt lines To: Thomas Gleixner Cc: Peter Zijlstra , linux-kernel@vger.kernel.org, ricardo.neri-calderon@linux.intel.com, marc.zyngier@arm.com, mingo@kernel.org References: <1531152846-19374-1-git-send-email-julien.thierry@arm.com> <1531152846-19374-2-git-send-email-julien.thierry@arm.com> <20180717155117.GJ2494@hirez.programming.kicks-ass.net> From: Julien Thierry Message-ID: <7016088c-1966-2207-60c5-29afc97eb58d@arm.com> Date: Wed, 18 Jul 2018 09:09:36 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 17/07/18 20:46, Thomas Gleixner wrote: > On Tue, 17 Jul 2018, Julien Thierry wrote: >> On 17/07/18 16:51, Peter Zijlstra wrote: >>> On Tue, Jul 17, 2018 at 04:48:17PM +0100, Julien Thierry wrote: >>>> Supporting desc->affinity_hint for NMIs shouldn't be an issue, right? >>> >>> Shouldn't NMIs be strictly per cpu interrupt sources? >> >> That's a good question, and I don't have a proper answer right now... >> >> However, per cpu or not, the affinity still needs to be set for that >> interrupt. It seemed to me that the desc->affinity_hint was just a way to keep >> track of the interrupt affinity when it gets set through >> irq_set_affinity_hint. >> >> Is that not the case? > > No the affinity hint is a way to tell user space irqbalanced what the > driver thinks is the best placement. Affinity settings are done by the > kernel internal interfaces and those do not care about the hint at all. > Oh, I see. Thanks for explaining I already do set the IRQF_NOBALANCING for NMIs, so fiddling with that should be already limited. I'll consider setting the IRQF_PERCPU (or mandating it for the NMI requests). Thanks, -- Julien Thierry