From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx150.postini.com [74.125.245.150]) by kanga.kvack.org (Postfix) with SMTP id C75BB6B005D for ; Tue, 21 Aug 2012 20:36:29 -0400 (EDT) Date: Wed, 22 Aug 2012 03:37:24 +0300 From: "Michael S. Tsirkin" Subject: Re: [PATCH v7 2/4] virtio_balloon: introduce migration primitives to balloon pages Message-ID: <20120822003723.GL9027@redhat.com> References: <20120814182244.GB13338@t510.redhat.com> <20120814195139.GA28870@redhat.com> <20120814201113.GE22133@t510.redhat.com> <20120815090528.GH4052@csn.ul.ie> <20120815092528.GA29214@redhat.com> <20120815094839.GJ4052@csn.ul.ie> <20120815100108.GA1999@redhat.com> <20120815111651.GL4052@csn.ul.ie> <20120815112851.GA2707@redhat.com> <87mx1o3j5y.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87mx1o3j5y.fsf@rustcorp.com.au> Sender: owner-linux-mm@kvack.org List-ID: To: Rusty Russell Cc: Mel Gorman , Rafael Aquini , linux-mm@kvack.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Rik van Riel , Andi Kleen , Andrew Morton , Konrad Rzeszutek Wilk , Minchan Kim On Tue, Aug 21, 2012 at 03:01:37PM +0930, Rusty Russell wrote: > On Wed, 15 Aug 2012 14:28:51 +0300, "Michael S. Tsirkin" wrote: > > On Wed, Aug 15, 2012 at 12:16:51PM +0100, Mel Gorman wrote: > > > I was thinking of exactly that page->mapping == balloon_mapping check. As I > > > do not know how many active balloon drivers there might be I cannot guess > > > in advance how much of a scalability problem it will be. > > > > Not at all sure multiple drivers are worth supporting, but multiple > > *devices* is I think worth supporting, if for no other reason than that > > they can work today. For that, we need a device pointer which Rafael > > wants to put into the mapping, this means multiple balloon mappings. > > Rafael, please make sure that the balloon driver fails on the second and > subsequent balloon devices. > > Michael, we only allow multiple balloon devices because it fell out of > the implementation. If it causes us even the slightest issue, we should > not support it. It's not a sensible setup. > > Cheers, > Rusty. Looks like latest revision does it using a flag which seems cleaner, so I think the point is moot. -- MST -- 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