From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx183.postini.com [74.125.245.183]) by kanga.kvack.org (Postfix) with SMTP id 89CB66B005D for ; Wed, 3 Oct 2012 05:09:49 -0400 (EDT) Date: Wed, 3 Oct 2012 10:09:14 +0100 From: Will Deacon Subject: Re: [PATCH v2] mm: thp: Set the accessed flag for old pages on access fault. Message-ID: <20121003090914.GA22445@mudshark.cambridge.arm.com> References: <1349197151-19645-1-git-send-email-will.deacon@arm.com> <20121002150104.da57fa94.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20121002150104.da57fa94.akpm@linux-foundation.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "linux-arch@vger.kernel.org" , "mhocko@suse.cz" , "kirill@shutemov.name" , Andrea Arcangeli , Chris Metcalf , Steve Capper On Tue, Oct 02, 2012 at 11:01:04PM +0100, Andrew Morton wrote: > On Tue, 2 Oct 2012 17:59:11 +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. > > Alas, the code you're altering has changed so much in linux-next that I > am reluctant to force this fix in there myself. Can you please > redo/retest/resend? You can do that on 3.7-rc1 if you like, then we > can feed this into -rc2. No problem. I'll rebase the entire ARM series at -rc1 prior to posting anyway, so this can be included in that lot. > > --- a/mm/memory.c > > +++ b/mm/memory.c > > @@ -3524,7 +3524,8 @@ retry: > > > > barrier(); > > if (pmd_trans_huge(orig_pmd)) { > > - if (flags & FAULT_FLAG_WRITE && > > + int dirty = flags & FAULT_FLAG_WRITE; > > `flags' is `unsigned int', so making `dirty' match that is nicer. I'll fold that in with the above. Cheers, Will -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org