From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 139EFC43381 for ; Mon, 4 Mar 2019 13:16:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D66FF20830 for ; Mon, 4 Mar 2019 13:16:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726836AbfCDNQy (ORCPT ); Mon, 4 Mar 2019 08:16:54 -0500 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:33522 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726472AbfCDNQx (ORCPT ); Mon, 4 Mar 2019 08:16:53 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id F35CEEBD; Mon, 4 Mar 2019 05:16:52 -0800 (PST) Received: from [10.1.196.69] (e112269-lin.cambridge.arm.com [10.1.196.69]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5F6333F575; Mon, 4 Mar 2019 05:16:49 -0800 (PST) Subject: Re: [PATCH v3 08/34] ia64: mm: Add p?d_large() definitions To: "Kirill A. Shutemov" Cc: Mark Rutland , linux-ia64@vger.kernel.org, Peter Zijlstra , Catalin Marinas , Dave Hansen , Will Deacon , linux-mm@kvack.org, "H. Peter Anvin" , "Liang, Kan" , x86@kernel.org, Ingo Molnar , Fenghua Yu , Arnd Bergmann , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Borislav Petkov , Andy Lutomirski , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, Tony Luck , Ard Biesheuvel , linux-kernel@vger.kernel.org, James Morse References: <20190227170608.27963-1-steven.price@arm.com> <20190227170608.27963-9-steven.price@arm.com> <20190301215728.nk7466zohdlgelcb@kshutemo-mobl1> From: Steven Price Message-ID: <15100043-26e4-2ee1-28fe-101e12f74926@arm.com> Date: Mon, 4 Mar 2019 13:16:47 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.0 MIME-Version: 1.0 In-Reply-To: <20190301215728.nk7466zohdlgelcb@kshutemo-mobl1> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/03/2019 21:57, Kirill A. Shutemov wrote: > On Wed, Feb 27, 2019 at 05:05:42PM +0000, Steven Price wrote: >> walk_page_range() is going to be allowed to walk page tables other than >> those of user space. For this it needs to know when it has reached a >> 'leaf' entry in the page tables. This information is provided by the >> p?d_large() functions/macros. >> >> For ia64 leaf entries are always at the lowest level, so implement >> stubs returning 0. > > Are you sure about this? I see pte_mkhuge defined for ia64 and Kconfig > contains hugetlb references. > I'm not completely familiar with ia64, but my understanding is that it doesn't have the situation where a page table walk ends early - there is always the full depth of entries. The p?d_huge() functions always return 0. However my understanding is that it does support huge TLB entries, so when populating the TLB a region larger than a standard page can be mapped. I'd definitely welcome review by someone more familiar with ia64 to check my assumptions. Thanks, Steve