From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f71.google.com (mail-pg0-f71.google.com [74.125.83.71]) by kanga.kvack.org (Postfix) with ESMTP id B41F26B025E for ; Fri, 9 Dec 2016 11:40:12 -0500 (EST) Received: by mail-pg0-f71.google.com with SMTP id p66so47720445pga.4 for ; Fri, 09 Dec 2016 08:40:12 -0800 (PST) Received: from mga14.intel.com (mga14.intel.com. [192.55.52.115]) by mx.google.com with ESMTPS id m29si34538654pgn.94.2016.12.09.08.40.11 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 09 Dec 2016 08:40:11 -0800 (PST) Date: Fri, 9 Dec 2016 08:40:11 -0800 From: Andi Kleen Subject: Re: [RFC, PATCHv1 00/28] 5-level paging Message-ID: <20161209164011.GL8388@tassilo.jf.intel.com> References: <20161208162150.148763-1-kirill.shutemov@linux.intel.com> <20161209050130.GC2595@gmail.com> <20161209103722.GE30380@node.shutemov.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161209103722.GE30380@node.shutemov.name> Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: Ingo Molnar , "Kirill A. Shutemov" , Linus Torvalds , Andrew Morton , x86@kernel.org, Thomas Gleixner , Ingo Molnar , Arnd Bergmann , "H. Peter Anvin" , Dave Hansen , Andy Lutomirski , linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org > On other hand, large virtual address space would put more pressure on > cache -- at least one more page table per process, if we make 56-bit VA > default. The top level page always has to be there unless you disable it at boot time (unless you go for a scheme where some processes share top level pages, and others do not, which would likely be very complicated) But even with that it is more than one: A typical set up has at least two extra 4K pages overhead, one for the bottom and one for the top mappings. Could easily be more. -Andi -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org