From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: [PATCH v2] x86: PAT: Documentation: rewrite "MTRR effects on PAT / non-PAT systems" Date: Sat, 5 Mar 2016 12:52:55 +0100 Message-ID: <20160305115255.GA11846@gmail.com> References: <20160304210900.GT3577@linux.vnet.ibm.com> <1457131501-14855-1-git-send-email-mcgrof@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1457131501-14855-1-git-send-email-mcgrof@kernel.org> Sender: linux-kernel-owner@vger.kernel.org To: "Luis R. Rodriguez" Cc: paulmck@linux.vnet.ibm.com, bp@alien8.de, 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 List-Id: linux-arch.vger.kernel.org * Luis R. Rodriguez wrote: > The current documentation refers to using set_memory_wc() as a > possible hole strategy when you have overlapping ioremap() regions, The whole explanation should talk about virtual aliases over the same physical address, not some 'overlapping regions'. I see where this talk about 'overlap' comes: the memtype rbtree in arch/x86/mm/pat_rbtree.c indeed has memtype ranges that may overlap on the physical side. But it is highly confusing to call this 'overlapping' on the driver API documentation level without making it really clear what it's about. Thanks, Ingo From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f66.google.com ([74.125.82.66]:35239 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753628AbcCELxB (ORCPT ); Sat, 5 Mar 2016 06:53:01 -0500 Date: Sat, 5 Mar 2016 12:52:55 +0100 From: Ingo Molnar Subject: Re: [PATCH v2] x86: PAT: Documentation: rewrite "MTRR effects on PAT / non-PAT systems" Message-ID: <20160305115255.GA11846@gmail.com> References: <20160304210900.GT3577@linux.vnet.ibm.com> <1457131501-14855-1-git-send-email-mcgrof@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1457131501-14855-1-git-send-email-mcgrof@kernel.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: "Luis R. Rodriguez" Cc: paulmck@linux.vnet.ibm.com, bp@alien8.de, 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: <20160305115255.H7ElDmEL7dNI_vfR5ZBBYyIJGa4T6tJisYDrlfpIyYg@z> * Luis R. Rodriguez wrote: > The current documentation refers to using set_memory_wc() as a > possible hole strategy when you have overlapping ioremap() regions, The whole explanation should talk about virtual aliases over the same physical address, not some 'overlapping regions'. I see where this talk about 'overlap' comes: the memtype rbtree in arch/x86/mm/pat_rbtree.c indeed has memtype ranges that may overlap on the physical side. But it is highly confusing to call this 'overlapping' on the driver API documentation level without making it really clear what it's about. Thanks, Ingo