From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932251AbeBSXTq (ORCPT ); Mon, 19 Feb 2018 18:19:46 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:60419 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932169AbeBSXTp (ORCPT ); Mon, 19 Feb 2018 18:19:45 -0500 Date: Tue, 20 Feb 2018 00:19:49 +0100 (CET) From: Thomas Gleixner To: Reinette Chatre cc: fenghua.yu@intel.com, tony.luck@intel.com, gavin.hindman@intel.com, vikas.shivappa@linux.intel.com, dave.hansen@intel.com, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH V2 11/22] x86/intel_rdt: Associate pseudo-locked regions with its domain In-Reply-To: <7bd1f8e8-116f-bdb2-23d2-a94f9a21e028@intel.com> Message-ID: References: <216ad1ef8314dc578a900ff8b06248464f5aa2ee.1518443616.git.reinette.chatre@intel.com> <7bd1f8e8-116f-bdb2-23d2-a94f9a21e028@intel.com> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 19 Feb 2018, Reinette Chatre wrote: > Hi Thomas, > > On 2/19/2018 1:19 PM, Thomas Gleixner wrote: > > On Tue, 13 Feb 2018, Reinette Chatre wrote: > > > >> After a pseudo-locked region is locked it needs to be associated with > >> the RDT domain representing the pseudo-locked cache so that its life > >> cycle can be managed correctly. > >> > >> Only a single pseudo-locked region can exist on any cache instance so we > >> maintain a single pointer to a pseudo-locked region from each RDT > >> domain. > > > > Why is only a single pseudo locked region possible? > > The setup of a pseudo-locked region requires the usage of wbinvd. If a > second pseudo-locked region is thus attempted it will evict the > pseudo-locked data of the first. Why does it neeed wbinvd? wbinvd is a big hammer. What's wrong with clflush? Thanks, tglx