Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755170AbcLOVO3 (ORCPT ); Thu, 15 Dec 2016 16:14:29 -0500 Received: from terminus.zytor.com ([198.137.202.10]:38540 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753382AbcLOVO1 (ORCPT ); Thu, 15 Dec 2016 16:14:27 -0500 User-Agent: K-9 Mail for Android In-Reply-To: <20161215192017.GP8388@tassilo.jf.intel.com> References: <20161208162150.148763-1-kirill.shutemov@linux.intel.com> <20161208162150.148763-17-kirill.shutemov@linux.intel.com> <20161208200505.c6xiy56oufg6d24m@pd.tnic> <20161208202013.uutsny6avn5gimwq@pd.tnic> <20161215143944.ruxr6r3b2atg4tnf@pd.tnic> <20161215190902.tdle4uj27xkc3x4i@pd.tnic> <20161215192017.GP8388@tassilo.jf.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Subject: Re: [RFC, PATCHv1 15/28] x86: detect 5-level paging support From: hpa@zytor.com Date: Thu, 15 Dec 2016 12:57:43 -0800 To: Andi Kleen , Borislav Petkov CC: Linus Torvalds , "Kirill A. Shutemov" , Andrew Morton , the arch/x86 maintainers , Thomas Gleixner , Ingo Molnar , Arnd Bergmann , Dave Hansen , Andy Lutomirski , "linux-arch@vger.kernel.org" , linux-mm , Linux Kernel Mailing List Message-ID: <34A313BB-EB15-4A4C-AB77-BD678118F086@zytor.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 531 Lines: 11 On December 15, 2016 11:20:17 AM PST, Andi Kleen wrote: > >The code is not calling CPUID in any performance critical path, only >at initialization. So any discussion about saving a few instructions >is a complete waste of time. > >-Andi NB: the chief offender is Loadlin, which is still used in some manufacturing flows that depends on a mix of legacy DOS and Linux applications; however, older versions of LILO also have this problem. -- Sent from my Android device with K-9 Mail. Please excuse my brevity.