Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753186AbcCWU7M (ORCPT ); Wed, 23 Mar 2016 16:59:12 -0400 Received: from mail-wm0-f50.google.com ([74.125.82.50]:34588 "EHLO mail-wm0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750938AbcCWU7K (ORCPT ); Wed, 23 Mar 2016 16:59:10 -0400 Date: Wed, 23 Mar 2016 20:59:06 +0000 From: Matt Fleming To: Vikas Shivappa Cc: dsahern@gmail.com, namhyung@kernel.org, mingo@kernel.org, peterz@infradead.org, brgerst@gmail.com, bp@alien8.de, dvlasenk@redhat.com, vincent.weaver@maine.edu, torvalds@linux-foundation.org, eranian@google.com, tony.luck@intel.com, tglx@linutronix.de, alexander.shishkin@linux.intel.com, linux-kernel@vger.kernel.org, luto@amacapital.net, hpa@zytor.com, jolsa@redhat.com, acme@redhat.com, linux-tip-commits@vger.kernel.org Subject: Re: [tip:perf/urgent] perf/x86/mbm: Implement RMID recycling Message-ID: <20160323205906.GI11676@codeblueprint.co.uk> References: <1457652732-4499-6-git-send-email-vikas.shivappa@linux.intel.com> <20160321150905.GD11676@codeblueprint.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24+41 (02bc14ed1569) (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 374 Lines: 9 On Mon, 21 Mar, at 11:27:55AM, Vikas Shivappa wrote: > > The init_mbm_sample calls the update_sample to read the MSR in IPI .. Since > the count is also in IPI , they should not trash each other ? > > Basically all the MSR read/writes are in high irql , except for the mbm > overflow timer and read calls which holds an irqsave spinlock. Good point! This should be fine.