From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx158.postini.com [74.125.245.158]) by kanga.kvack.org (Postfix) with SMTP id B56116B0044 for ; Wed, 15 Aug 2012 05:05:31 -0400 (EDT) Date: Wed, 15 Aug 2012 10:05:28 +0100 From: Mel Gorman Subject: Re: [PATCH v7 2/4] virtio_balloon: introduce migration primitives to balloon pages Message-ID: <20120815090528.GH4052@csn.ul.ie> References: <20120813084123.GF14081@redhat.com> <20120814182244.GB13338@t510.redhat.com> <20120814195139.GA28870@redhat.com> <20120814201113.GE22133@t510.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20120814201113.GE22133@t510.redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Rafael Aquini Cc: "Michael S. Tsirkin" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Rusty Russell , Rik van Riel , Andi Kleen , Andrew Morton , Konrad Rzeszutek Wilk , Minchan Kim On Tue, Aug 14, 2012 at 05:11:13PM -0300, Rafael Aquini wrote: > On Tue, Aug 14, 2012 at 10:51:39PM +0300, Michael S. Tsirkin wrote: > > What I think you should do is use rcu for access. > > And here sync rcu before freeing. > > Maybe an overkill but at least a documented synchronization > > primitive, and it is very light weight. > > > > I liked your suggestion on barriers, as well. > I have not thought about this as deeply as I shouold but is simply rechecking the mapping under the pages_lock to make sure the page is still a balloon page an option? i.e. use pages_lock to stabilise page->mapping. -- Mel Gorman SUSE Labs -- 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