Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753035Ab2F2WaK (ORCPT ); Fri, 29 Jun 2012 18:30:10 -0400 Received: from terminus.zytor.com ([198.137.202.10]:50602 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751054Ab2F2WaI (ORCPT ); Fri, 29 Jun 2012 18:30:08 -0400 Message-ID: <4FEE2C4B.7040405@zytor.com> Date: Fri, 29 Jun 2012 15:29:31 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:13.0) Gecko/20120605 Thunderbird/13.0 MIME-Version: 1.0 To: Cyclonus J CC: Konrad Rzeszutek Wilk , marmarek@invisiblethingslab.com, xen-devel@lists.xensource.com, x86@kernel.org, Jason Garrett-Glaser , linux-kernel@vger.kernel.org, rostedt@goodmis.org, mingo@redhat.com, tglx@linutronix.de, "Siddha, Suresh B" Subject: Re: [Xen-devel] [PATCH] x86 fixes for 3.3 impacting distros (v1). References: <1328888091-9692-1-git-send-email-konrad.wilk@oracle.com> <20120510153457.GB6389@phenom.dumpdata.com> <20120627231755.GA1021@gmail.com> <20120628142836.GE8956@phenom.dumpdata.com> <4FEC6D44.8080807@zytor.com> <20120629215225.GA7544@gmail.com> In-Reply-To: <20120629215225.GA7544@gmail.com> X-Enigmail-Version: 1.4.2 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1030 Lines: 27 On 06/29/2012 02:52 PM, Cyclonus J wrote: > > Peter, > > hmm, It looks like option 1 doesn't have any perf regression, but it is still > not acceptable? That is fine. If you prefer to have a software PAT table lookup, could you provide > some details so I can try to get something align that direction? > It has no perf regression, but it really buries deep in the code a strange abstraction which only happens to work on Xen and is confusing as hell. The idea with a software PAT table is that the PAT numbers used by the kernel should come from a table in the kernel instead of being hard-coded. That might take some work, and it remains to be seen if it is practical. It *may* be that we need to hard-code 0 as WB, still, but that should be true on any sane platform. -hpa -- 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/