From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751500AbdAWURo (ORCPT ); Mon, 23 Jan 2017 15:17:44 -0500 Received: from mga06.intel.com ([134.134.136.31]:26686 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751280AbdAWURm (ORCPT ); Mon, 23 Jan 2017 15:17:42 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.33,275,1477983600"; d="scan'208";a="56336831" Date: Mon, 23 Jan 2017 12:18:07 -0800 (PST) From: Shivappa Vikas X-X-Sender: vikas@vshiva-Udesk To: Thomas Gleixner cc: Vikas Shivappa , vikas.shivappa@intel.com, linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, mingo@kernel.org, peterz@infradead.org, ravi.v.shankar@intel.com, tony.luck@intel.com, fenghua.yu@intel.com, h.peter.anvin@intel.com Subject: Re: [PATCH 8/8] x86/intel_rdt: rmdir,umount and hotcpu updates for MBA In-Reply-To: Message-ID: References: <1484076788-25385-1-git-send-email-vikas.shivappa@linux.intel.com> <1484076788-25385-9-git-send-email-vikas.shivappa@linux.intel.com> User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 16 Jan 2017, Thomas Gleixner wrote: > On Tue, 10 Jan 2017, Vikas Shivappa wrote: > >> During rmdir only reset the ctrl values for the rdtgroup's closid. This >> is done so that that next time when the closid is reused they dont >> reflect old values. > > How on earth is that related to MBA? This is not specific to MBA so i put it as x86/intel_rdt in the subject but will send this as part of seperate series which you mentioned. > >> Remove the closid update during cpuonline in cqm as its >> already in the CAT code. Since both cqm and CAT want the rmid and closid >> to be zero when cpu is online, remove the PQR MSR write to zero during >> cpuonline because the MSRs are at zero after cpu reset and also during > > Are you sure that the MSRs are zero when the cpu goes offline and then > online again? That's not a reset. Thats right - I was removing this since at the first sched_in the new CLOSID would be updated anyways. I know this prevents from having a 0 CLOSid at the time all the hot plug code is run, but we already have run the __cpu_disable and all the hotplug code when going down on the last used CLOSid. (if the kernel thread that handles the offline/online should have a 0 CLOS then thats fine probably..) So may be the right way is to actually zero the CLOS in PQR_MSR when we are going down/offline ? Thanks, Vikas > > Thanks, > > tglx >