From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:36947 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755567AbcCEBDx (ORCPT ); Fri, 4 Mar 2016 20:03:53 -0500 Date: Sat, 5 Mar 2016 02:03:46 +0100 From: "Luis R. Rodriguez" Subject: Re: [PATCH v2] x86: PAT: Documentation: rewrite "MTRR effects on PAT / non-PAT systems" Message-ID: <20160305010346.GW25240@wotan.suse.de> References: <20160304210900.GT3577@linux.vnet.ibm.com> <1457131501-14855-1-git-send-email-mcgrof@kernel.org> <20160305000304.GA3577@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160305000304.GA3577@linux.vnet.ibm.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: "Paul E. McKenney" , bp@alien8.de Cc: "Luis R. Rodriguez" , mingo@kernel.org, tglx@linutronix.de, hpa@zytor.com, toshi.kani@hp.com, airlied@redhat.com, benh@kernel.crashing.org, mst@redhat.com, vinod.koul@intel.com, jgross@suse.com, daniel.vetter@ffwll.ch, luto@amacapital.net, davem@davemloft.net, ben@decadent.org.uk, benjamin.poirier@gmail.com, linux-fbdev@vger.kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org, linux-doc@vger.kernel.org, corbet@lwn.net Message-ID: <20160305010346.fcqowarW7typV0jA3O06-jOFanN0h7HIXAYUgdphJYY@z> On Fri, Mar 04, 2016 at 04:03:04PM -0800, Paul E. McKenney wrote: > On Fri, Mar 04, 2016 at 02:45:01PM -0800, Luis R. Rodriguez wrote: > > The current documentation refers to using set_memory_wc() as a > > possible hole strategy when you have overlapping ioremap() regions, > > that's incorrect as set_memory_*() helpers can only be used on RAM, > > not IO memory. Using set_memory_wc() will not fail, that's a problem > > which must be corrected in the future. This fixes that, and updates > > the documention to *strongly* discourage overlapping ioremap() memory > > uses, but also documents a possible solution should there really be > > no other option to remain compatible on both PAT and MTRR memory > > constarained systems. While at it, this provides some same guidlines > > to system designers to remain sane and compatible on both PAT and > > non-PAT systems. > > > > As per Toshi this also fixes the table for the effective memory type > > when using MTRR WC on PAT UC- to WC. > > > > Signed-off-by: Luis R. Rodriguez > > And I was really confused during my earlier reply. For some reason > I read the filename as memory-barriers.txt. > > This one is not mine. Too much time in standards committee meetings, > I guess. ;-) Heh, OK yeah I was confused why you wanted to pick it up but played along. Boris, can this go through you as its a follow up that previously went through you ? Luis