Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753821AbbHCPJc (ORCPT ); Mon, 3 Aug 2015 11:09:32 -0400 Received: from g2t2354.austin.hp.com ([15.217.128.53]:34662 "EHLO g2t2354.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753585AbbHCPJb (ORCPT ); Mon, 3 Aug 2015 11:09:31 -0400 Message-ID: <1438614488.3214.466.camel@hp.com> Subject: Re: [PATCH] x86, pat: Add comments to cachemode translation tables From: Toshi Kani To: Thomas Gleixner Cc: Jan Beulich , peterz@infradead.org, mingo@kernel.org, x86@kernel.org, bp@suse.de, linux-kernel@vger.kernel.org Date: Mon, 03 Aug 2015 09:08:08 -0600 In-Reply-To: References: <1437588371-28223-1-git-send-email-toshi.kani@hp.com> <55B0A9110200007800094558@prv-mh.provo.novell.com> <1437661620.3214.281.camel@hp.com> <55B11B4D0200007800094AE9@prv-mh.provo.novell.com> <1437665107.3214.310.camel@hp.com> <55B126070200007800094BD5@prv-mh.provo.novell.com> <1437665929.3214.313.camel@hp.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.16.3 (3.16.3-2.fc22) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1360 Lines: 37 On Sun, 2015-08-02 at 12:07 +0200, Thomas Gleixner wrote: > On Thu, 23 Jul 2015, Toshi Kani wrote: > > On Thu, 2015-07-23 at 09:36 -0600, Jan Beulich wrote: > > > > > > > > > > On 23.07.15 at 17:25, wrote: > > > > Yes, I agree with you. But such risk is very low -- 1) the regular > > > > case > > > > (no fallback) is used most of the cases, 2) the code using WT knows > > > > what > > > > type of memory it is dealing with. For example, pmem may map NVDIMM > > > > > > > > with > > > > WT, and any sane BIOS sets MTRR to WB for NVDIMM. > > > > > > Do the words "sane" and "BIOS" really fit together in your opinion? > > > > :-) > > > > Anyway, I am not disagreeing with you... When UC is ready for both > > regular > > memory and IO memory, it should be changed to fall back to UC. > > What's the resolution of this discussion? Is that patch correct as is > or do we get an updated version? Yes, this patch is correct and we are in agreement. What Jan mentioned about falling back to UC, instead of UC-, is a separate item, and the code does not support it yet. Thanks, -Toshi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/