From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Price Date: Mon, 04 Mar 2019 13:16:47 +0000 Subject: Re: [PATCH v3 08/34] ia64: mm: Add p?d_large() definitions Message-Id: <15100043-26e4-2ee1-28fe-101e12f74926@arm.com> List-Id: References: <20190227170608.27963-1-steven.price@arm.com> <20190227170608.27963-9-steven.price@arm.com> <20190301215728.nk7466zohdlgelcb@kshutemo-mobl1> In-Reply-To: <20190301215728.nk7466zohdlgelcb@kshutemo-mobl1> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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 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