From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753388AbbAMUmE (ORCPT ); Tue, 13 Jan 2015 15:42:04 -0500 Received: from mta-out1.inet.fi ([62.71.2.227]:38897 "EHLO jenni2.inet.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752291AbbAMUmB (ORCPT ); Tue, 13 Jan 2015 15:42:01 -0500 Date: Tue, 13 Jan 2015 22:41:44 +0200 From: "Kirill A. Shutemov" To: Dave Hansen Cc: "Kirill A. Shutemov" , Andrew Morton , Hugh Dickins , linux-mm@kvack.org, Cyrill Gorcunov , Pavel Emelyanov , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] mm: rename mm->nr_ptes to mm->nr_pgtables Message-ID: <20150113204144.GA1865@node.dhcp.inet.fi> References: <1421176456-21796-1-git-send-email-kirill.shutemov@linux.intel.com> <1421176456-21796-2-git-send-email-kirill.shutemov@linux.intel.com> <54B581C7.50206@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <54B581C7.50206@linux.intel.com> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 13, 2015 at 12:36:23PM -0800, Dave Hansen wrote: > On 01/13/2015 11:14 AM, Kirill A. Shutemov wrote: > > pgd_t * pgd; > > atomic_t mm_users; /* How many users with user space? */ > > atomic_t mm_count; /* How many references to "struct mm_struct" (users count as 1) */ > > - atomic_long_t nr_ptes; /* Page table pages */ > > + atomic_long_t nr_pgtables; /* Page table pages */ > > int map_count; /* number of VMAs */ > > One more crazy idea... > > There are 2^9 possible pud pages, 2^18 pmd pages and 2^27 pte pages. > That's only 54 bits (technically minus one bit each because the upper > half of the address space is for the kernel). Does this math make sense for all architecures? IA64? Power? -- Kirill A. Shutemov