From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f182.google.com (mail-wi0-f182.google.com [209.85.212.182]) by kanga.kvack.org (Postfix) with ESMTP id E0ACB6B0038 for ; Tue, 12 May 2015 06:54:40 -0400 (EDT) Received: by wicmc15 with SMTP id mc15so50764096wic.1 for ; Tue, 12 May 2015 03:54:40 -0700 (PDT) Received: from johanna1.rokki.sonera.fi (mta-out1.inet.fi. [62.71.2.227]) by mx.google.com with ESMTP id ex8si1781243wjb.106.2015.05.12.03.54.38 for ; Tue, 12 May 2015 03:54:39 -0700 (PDT) Date: Tue, 12 May 2015 13:54:31 +0300 From: "Kirill A. Shutemov" Subject: Re: [PATCH v2 3/3] pagemap: switch to the new format and do some cleanup Message-ID: <20150512105431.GD18365@node.dhcp.inet.fi> References: <20150512090156.24768.2521.stgit@buzz> <20150512094306.24768.51325.stgit@buzz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150512094306.24768.51325.stgit@buzz> Sender: owner-linux-mm@kvack.org List-ID: To: Konstantin Khlebnikov Cc: linux-mm@kvack.org, Naoya Horiguchi , linux-kernel@vger.kernel.org, Andrew Morton , Mark Williamson , Pavel Emelyanov , linux-api@vger.kernel.org, Andy Lutomirski , Vlastimil Babka , Pavel Machek , Mark Seaborn , Linus Torvalds , Daniel James , Finn Grimwood On Tue, May 12, 2015 at 12:43:06PM +0300, Konstantin Khlebnikov wrote: > This patch removes page-shift bits (scheduled to remove since 3.11) and > completes migration to the new bit layout. Also it cleans messy macro. > > Signed-off-by: Konstantin Khlebnikov > --- > fs/proc/task_mmu.c | 152 ++++++++++++++++--------------------------------- > tools/vm/page-types.c | 29 +++------ > 2 files changed, 58 insertions(+), 123 deletions(-) > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > index 0b7a8ffec95f..66bc7207ce90 100644 > --- a/fs/proc/task_mmu.c > +++ b/fs/proc/task_mmu.c > @@ -710,23 +710,6 @@ const struct file_operations proc_tid_smaps_operations = { > .release = proc_map_release, > }; > > -/* > - * We do not want to have constant page-shift bits sitting in > - * pagemap entries and are about to reuse them some time soon. > - * > - * Here's the "migration strategy": > - * 1. when the system boots these bits remain what they are, > - * but a warning about future change is printed in log; > - * 2. once anyone clears soft-dirty bits via clear_refs file, > - * these flag is set to denote, that user is aware of the > - * new API and those page-shift bits change their meaning. > - * The respective warning is printed in dmesg; > - * 3. In a couple of releases we will remove all the mentions > - * of page-shift in pagemap entries. > - */ Wouldn't it be better to just have v2=1 by default for couple releases to see if anything breaks? This way we can revert easily if regression reported. I guess someone could miss this change coming if he didn't touch clear_refs. -- Kirill A. Shutemov -- 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