From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f177.google.com (mail-wi0-f177.google.com [209.85.212.177]) by kanga.kvack.org (Postfix) with ESMTP id A7B486B00A7 for ; Wed, 5 Nov 2014 10:21:15 -0500 (EST) Received: by mail-wi0-f177.google.com with SMTP id ex7so2307043wid.16 for ; Wed, 05 Nov 2014 07:21:15 -0800 (PST) Received: from mail-wi0-x22a.google.com (mail-wi0-x22a.google.com. [2a00:1450:400c:c05::22a]) by mx.google.com with ESMTPS id es4si17185740wib.5.2014.11.05.07.21.14 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 05 Nov 2014 07:21:14 -0800 (PST) Received: by mail-wi0-f170.google.com with SMTP id r20so325927wiv.5 for ; Wed, 05 Nov 2014 07:21:14 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <5457C6EA.3080809@intel.com> References: <1414771317-5721-1-git-send-email-standby24x7@gmail.com> <5457C6EA.3080809@intel.com> Date: Thu, 6 Nov 2014 00:21:14 +0900 Message-ID: Subject: Re: [PATCH] Documentation: vm: Add 1GB large page support information From: Masanari Iida Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen Cc: Jonathan Corbet , "linux-kernel@vger.kernel.org" , linux-mm@kvack.org, lcapitulino@redhat.com Luiz, Dave, Thanks for comments. I understand that there are some exception cases which doesn't support 1G large pages on newer CPUs. I like Dave's example, at the same time I would like to add "pdpe1gb flag" in the document. For example, x86 CPUs normally support 4K and 2M (1G if pdpe1gb flag exist). Masanari On Tue, Nov 4, 2014 at 3:18 AM, Dave Hansen wrote: > On 10/31/2014 09:01 AM, Masanari Iida wrote: >> --- a/Documentation/vm/hugetlbpage.txt >> +++ b/Documentation/vm/hugetlbpage.txt >> @@ -2,7 +2,8 @@ >> The intent of this file is to give a brief summary of hugetlbpage support in >> the Linux kernel. This support is built on top of multiple page size support >> that is provided by most modern architectures. For example, i386 >> -architecture supports 4K and 4M (2M in PAE mode) page sizes, ia64 >> +architecture supports 4K and 4M (2M in PAE mode) page sizes, x86_64 >> +architecture supports 4K, 2M and 1G (SandyBridge or later) page sizes. ia64 >> architecture supports multiple page sizes 4K, 8K, 64K, 256K, 1M, 4M, 16M, >> 256M and ppc64 supports 4K and 16M. A TLB is a cache of virtual-to-physical >> translations. Typically this is a very scarce resource on processor. > > I wouldn't mention SandyBridge. Not all x86 CPUs are Intel. :) > > Also, what of the Intel CPUs like the Xeon Phi or the Atom cores? I > have an IvyBridge (>= Sandybridge) mobile CPU in this laptop which does > not support 1G pages. > > I would axe the i386-specific reference and just say something generic like: > > For example, x86 CPUs normally support 4K and 2M (1G sometimes). > > -- 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