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=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 1DDEAC4332D for ; Thu, 19 Mar 2020 14:35:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E4AEF20BED for ; Thu, 19 Mar 2020 14:35:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727552AbgCSOfP (ORCPT ); Thu, 19 Mar 2020 10:35:15 -0400 Received: from foss.arm.com ([217.140.110.172]:37036 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727286AbgCSOfO (ORCPT ); Thu, 19 Mar 2020 10:35:14 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 07AFE30E; Thu, 19 Mar 2020 07:35:14 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3DFFC3F52E; Thu, 19 Mar 2020 07:35:13 -0700 (PDT) Date: Thu, 19 Mar 2020 14:35:11 +0000 From: Mark Rutland To: Tuan Phan Cc: patches@amperecomputing.com, Will Deacon , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] perf: dsu: Allow multiple devices share same IRQ. Message-ID: <20200319143510.GB4876@lakrids.cambridge.arm.com> References: <1584491176-31358-1-git-send-email-tuanphan@os.amperecomputing.com> <20200319143250.GA4876@lakrids.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200319143250.GA4876@lakrids.cambridge.arm.com> User-Agent: Mutt/1.11.1+11 (2f07cb52) (2018-12-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 19, 2020 at 02:32:51PM +0000, Mark Rutland wrote: > On Tue, Mar 17, 2020 at 05:26:15PM -0700, Tuan Phan wrote: > > Add IRQF_SHARED flag when register IRQ such that multiple dsu > > devices can share same IRQ. > > > > Signed-off-by: Tuan Phan > > I don't think that this makes sense; further I think that this > highlights that the current driver doesn't support such a configuration > for other reasons. > > A DSU instance can only be accessed from a CPU associated with it, since > it's accessed via sysregs. The IRQ handler must run on one of those > CPUs. > > To handle that, the DSU PMU driver will need to gain an understanding of > which CPUs are associated with the instance. As it stands the driver > seems to assume that there's a single DSU instance, and that all CPUs > are affine to that same instance. Sorry, I misread dsu_pmu_get_online_cpu_any_but(), multiple instances are handled already. > So NAK to this patch, given the above. Regardless, this NAK stands. Thanks, Mark.