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[192.55.52.93]) by mx.google.com with ESMTPS id x14si5822540pgh.98.2019.03.04.11.06.38 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 04 Mar 2019 11:06:38 -0800 (PST) Received-SPF: pass (google.com: domain of tony.luck@intel.com designates 192.55.52.93 as permitted sender) client-ip=192.55.52.93; Authentication-Results: mx.google.com; spf=pass (google.com: domain of tony.luck@intel.com designates 192.55.52.93 as permitted sender) smtp.mailfrom=tony.luck@intel.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga102.fm.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) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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