From: Jeremy Fitzhardinge <jeremy@goop.org>
Subject: Re: [PATCH] Allow lazy unmapping by taking extra page references
 V2
Date: Tue, 23 Oct 2007 22:08:47 -0700
Message-ID: <471ED35F.3020605@goop.org>
References: <alpine.DEB.0.9999.0710212015430.2320@twinlark.arctic.org> <471C1A61.1010001@goop.org> <p73sl439s7k.fsf@bingen.suse.de> <471CEEB4.9040807@goop.org> <20071022190740.GA1695@one.firstfloor.org> <20071022223224.GC995458@sgi.com> <20071022233514.GA9057@one.firstfloor.org> <20071023003641.GF995458@sgi.com> <20071023070414.GM66820511@sgi.com> <20071023093035.GB24536@one.firstfloor.org> <20071024043619.GE66820511@sgi.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Return-path: <linux-kernel-owner+glk-linux-kernel-3=40m.gmane.org-S1756562AbXJXFI7@vger.kernel.org>
In-Reply-To: <20071024043619.GE66820511@sgi.com>
Sender: linux-kernel-owner@vger.kernel.org
To: David Chinner <dgc@sgi.com>
Cc: Andi Kleen <andi@firstfloor.org>, dean gaudet <dean@arctic.org>, Nick Piggin <nickpiggin@yahoo.com.au>, Xen-devel <xen-devel@lists.xensource.com>, Morten@suse.de, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, =?ISO-8859-1?Q?B=F8geskov?= <xen-users@morten.bogeskov.dk>, xfs@oss.sgi.com, xfs-masters@oss.sgi.com, Mark Williamson <mark.williamson@cl.cam.ac.uk>
List-Id: xen-devel@lists.xenproject.org

David Chinner wrote:
> Allow lazy unmapping of vmap()d regions be taking a reference
> on each page in the region being vmap()ed. The page references
> get released after the region is vunmap()ed, thereby ensuring
> we don't leave stray mappings on freed pages that could lead to
> problems pages being reallocated with incorrect mappings
> associated with them.
>
> Tested with XFS filesystems with 64k directory blocks with
> dirstress and XFSQA.
>
> Version 2:
>   - drop the release function stuff and just call put_page()
>     as it falls down to the same code in all calling cases.
>   

This doesn't apply cleanly to the current git tree.

    J