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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 B91D4C43381 for ; Mon, 4 Mar 2019 19:06:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9163820823 for ; Mon, 4 Mar 2019 19:06:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727355AbfCDTGj (ORCPT ); Mon, 4 Mar 2019 14:06:39 -0500 Received: from mga09.intel.com ([134.134.136.24]:6293 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726073AbfCDTGi (ORCPT ); Mon, 4 Mar 2019 14:06:38 -0500 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 04 Mar 2019 11:06:38 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,441,1544515200"; d="scan'208";a="128940141" Received: from agluck-desk.sc.intel.com (HELO agluck-desk) ([10.3.52.160]) by fmsmga008.fm.intel.com with ESMTP; 04 Mar 2019 11:06:37 -0800 Date: Mon, 4 Mar 2019 11:06:37 -0800 From: "Luck, Tony" To: Steven Price Cc: "Kirill A. Shutemov" , 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 , =?iso-8859-1?B?Suly9G1l?= Glisse , Borislav Petkov , Andy Lutomirski , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, Ard Biesheuvel , linux-kernel@vger.kernel.org, James Morse Subject: Re: [PATCH v3 08/34] ia64: mm: Add p?d_large() definitions Message-ID: <20190304190637.GA13947@agluck-desk> References: <20190227170608.27963-1-steven.price@arm.com> <20190227170608.27963-9-steven.price@arm.com> <20190301215728.nk7466zohdlgelcb@kshutemo-mobl1> <15100043-26e4-2ee1-28fe-101e12f74926@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <15100043-26e4-2ee1-28fe-101e12f74926@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 04, 2019 at 01:16:47PM +0000, Steven Price wrote: > 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. ia64 has several ways to manage page tables. The one used by Linux has multi-level table walks like other architectures, but we don't allow mixing of different page sizes within a "region" (there are eight regions selected by the high 3 bits of the virtual address). Is the series in some GIT tree that I can pull, rather than tracking down all 34 pieces? I can try it out and see if things work/break. -Tony