From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <owner-linux-mm@kvack.org>
Received: from psmtp.com (na3sys010amx124.postini.com [74.125.245.124])
	by kanga.kvack.org (Postfix) with SMTP id E829A6B0031
	for <linux-mm@kvack.org>; Wed, 24 Jul 2013 12:23:35 -0400 (EDT)
Received: by mail-ve0-f169.google.com with SMTP id m1so7227457ves.0
        for <linux-mm@kvack.org>; Wed, 24 Jul 2013 09:23:34 -0700 (PDT)
MIME-Version: 1.0
In-Reply-To: <20130724160826.GD24851@moon>
References: <20130724160826.GD24851@moon>
From: Andy Lutomirski <luto@amacapital.net>
Date: Wed, 24 Jul 2013 09:23:14 -0700
Message-ID: <CALCETrXYnkonpBANnUuX+aJ=B=EYFwecZO27yrqcEU8WErz9DA@mail.gmail.com>
Subject: Re: [PATCH] mm: Save soft-dirty bits on swapped pages
Content-Type: text/plain; charset=ISO-8859-1
Sender: owner-linux-mm@kvack.org
List-ID: <linux-mm.kvack.org>
To: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Linux MM <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>, Pavel Emelyanov <xemul@parallels.com>, Andrew Morton <akpm@linux-foundation.org>, Matt Mackall <mpm@selenic.com>, Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>, Marcelo Tosatti <mtosatti@redhat.com>, KOSAKI Motohiro <kosaki.motohiro@gmail.com>, Stephen Rothwell <sfr@canb.auug.org.au>

On Wed, Jul 24, 2013 at 9:08 AM, Cyrill Gorcunov <gorcunov@gmail.com> wrote:
> Andy Lutomirski reported that in case if a page with _PAGE_SOFT_DIRTY
> bit set get swapped out, the bit is getting lost and no longer
> available when pte read back.

Potentially silly question (due to my completely lack of understanding
of how swapping works in Linux): what about file-backed pages?
(Arguably these would be best supported by filesystems instead of by
the core vm, in which case it might make sense to drop soft-dirty
support for these pages entirely.)

--Andy

--
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: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>