From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751687AbeCLOcS (ORCPT ); Mon, 12 Mar 2018 10:32:18 -0400 Received: from mail-wm0-f68.google.com ([74.125.82.68]:33345 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751238AbeCLOcR (ORCPT ); Mon, 12 Mar 2018 10:32:17 -0400 X-Google-Smtp-Source: AG47ELvLg/2C1EweV/bUkzqJrjaQcbRJ6o0SUMLRmWlZTjhxSgZCKz+ukr+fidnpKrMowaPRGsu9Vg== Date: Mon, 12 Mar 2018 15:32:12 +0100 From: Ingo Molnar To: "Kirill A. Shutemov" Cc: Peter Zijlstra , kirill.shutemov@linux.intel.com, gorcunov@openvz.org, luto@amacapital.net, keescook@chromium.org, willy@infradead.org, torvalds@linux-foundation.org, tglx@linutronix.de, bp@suse.de, andy.shevchenko@gmail.com, linux-kernel@vger.kernel.org, hpa@zytor.com, ebiederm@xmission.com, jgross@suse.com, linux-tip-commits@vger.kernel.org Subject: Re: [tip:x86/mm] x86/boot/compressed/64: Describe the logic behind the LA57 check Message-ID: <20180312143212.77z2ptyqbsbqdll3@gmail.com> References: <20180226180451.86788-2-kirill.shutemov@linux.intel.com> <20180312124027.GG4064@hirez.programming.kicks-ass.net> <20180312124337.vw7bchm6brfzghfa@node.shutemov.name> <20180312131055.GH4064@hirez.programming.kicks-ass.net> <20180312140449.oyngtgqppnjuh3lf@node.shutemov.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180312140449.oyngtgqppnjuh3lf@node.shutemov.name> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Kirill A. Shutemov wrote: > > We can of course bike shed / benchmark this once my desktop refresh > > sports this feature, but ISTR this being one of the very first things > > Ingo mentioned when we started this whole 5L thing. > > I would rather not fix the problem that may not actually exist. :) That 5 level pagetables involve more overhead is a realy problem. By default we should only enable 5-level paging if memory mappings exist in the memory map that require the extended physical memory space. Thanks, Ingo