From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Kirill A. Shutemov" Subject: Re: [PATCH v2] mm: thp: Set the accessed flag for old pages on access fault. Date: Fri, 5 Oct 2012 01:13:54 +0300 Message-ID: <20121004221353.GA11454@shutemov.name> References: <1349197151-19645-1-git-send-email-will.deacon@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from shutemov.name ([176.9.204.213]:59712 "EHLO shutemov.name" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753179Ab2JDWNP (ORCPT ); Thu, 4 Oct 2012 18:13:15 -0400 Content-Disposition: inline In-Reply-To: <1349197151-19645-1-git-send-email-will.deacon@arm.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Will Deacon Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, akpm@linux-foundation.org, mhocko@suse.cz, Andrea Arcangeli , Chris Metcalf , Steve Capper On Tue, Oct 02, 2012 at 05:59:11PM +0100, Will Deacon wrote: > On x86 memory accesses to pages without the ACCESSED flag set result in the > ACCESSED flag being set automatically. With the ARM architecture a page access > fault is raised instead (and it will continue to be raised until the ACCESSED > flag is set for the appropriate PTE/PMD). > > For normal memory pages, handle_pte_fault will call pte_mkyoung (effectively > setting the ACCESSED flag). For transparent huge pages, pmd_mkyoung will only > be called for a write fault. > > This patch ensures that faults on transparent hugepages which do not result > in a CoW update the access flags for the faulting pmd. > > Cc: Andrea Arcangeli > Cc: Chris Metcalf > Signed-off-by: Steve Capper > Signed-off-by: Will Deacon Acked-by: Kirill A. Shutemov -- Kirill A. Shutemov