From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753044AbeD3JxV (ORCPT ); Mon, 30 Apr 2018 05:53:21 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:57112 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751300AbeD3JxU (ORCPT ); Mon, 30 Apr 2018 05:53:20 -0400 Subject: Re: [PATCH v2 0/6] arm64: provide pseudo NMI with GICv3 To: Joel Fernandes Cc: Linux ARM Kernel List , Linux Kernel Mailing List , mark.rutland@arm.com, marc.zyngier@arm.com, james.morse@arm.com, daniel.thompson@linaro.org, Joel Fernandes References: <1516190084-18978-1-git-send-email-julien.thierry@arm.com> From: Julien Thierry Message-ID: <07a0b8c1-3d87-0cae-61df-dbff782be301@arm.com> Date: Mon, 30 Apr 2018 10:53:17 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 29/04/18 07:37, Joel Fernandes wrote: > On Wed, Jan 17, 2018 at 4:10 AM, Julien Thierry wrote: >> Hi, >> >> On 17/01/18 11:54, Julien Thierry wrote: >>> >>> This series is a continuation of the work started by Daniel [1]. The goal >>> is to use GICv3 interrupt priorities to simulate an NMI. >>> >> >> >> I have submitted a separate series making use of this feature for the ARM >> PMUv3 interrupt [1]. > > I guess the hard lockup detector using NMI could be a nice next step > to see how well it works with lock up detection. That's the main > usecase for my interest. However, perf profiling is also a strong one. > From my understanding, Linux's hardlockup detector already uses the ARM PMU interrupt to check whether some task is stuck. I haven't looked at the details of the implementation yet, but in theory having the PMU interrupt as NMI should make the hard lockup detector use the NMI. When I do the v3, I'll have a look at this to check whether the hardlockup detector works fine when using NMI. Cheers, -- Julien Thierry