From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx130.postini.com [74.125.245.130]) by kanga.kvack.org (Postfix) with SMTP id 40C6C6B005D for ; Tue, 14 Aug 2012 16:30:25 -0400 (EDT) Date: Tue, 14 Aug 2012 23:31:23 +0300 From: "Michael S. Tsirkin" Subject: Re: [PATCH v7 2/4] virtio_balloon: introduce migration primitives to balloon pages Message-ID: <20120814203123.GC28990@redhat.com> 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=us-ascii Content-Disposition: inline In-Reply-To: <20120814201113.GE22133@t510.redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Rafael Aquini Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Rusty Russell , Rik van Riel , Mel Gorman , 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. > > Rik, Mel ? Further instead of simple assignment I would add an api in mm to set/clear the balloon mapping, with proper locking. This could fail if already set, and thus fix crash with many ballons. -- 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