Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753678AbZFVS6A (ORCPT ); Mon, 22 Jun 2009 14:58:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751349AbZFVS5v (ORCPT ); Mon, 22 Jun 2009 14:57:51 -0400 Received: from x35.xmailserver.org ([64.71.152.41]:33655 "EHLO x35.xmailserver.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750776AbZFVS5u (ORCPT ); Mon, 22 Jun 2009 14:57:50 -0400 X-AuthUser: davidel@xmailserver.org Date: Mon, 22 Jun 2009 11:51:42 -0700 (PDT) From: Davide Libenzi X-X-Sender: davide@makko.or.mcafeemobile.com To: "Michael S. Tsirkin" cc: Gregory Haskins , kvm@vger.kernel.org, Linux Kernel Mailing List , avi@redhat.com, paulmck@linux.vnet.ibm.com, Ingo Molnar , Rusty Russell Subject: Re: [PATCH 3/3] eventfd: add internal reference counting to fix notifier race conditions In-Reply-To: <20090622184139.GG15228@redhat.com> Message-ID: References: <4A3D895C.7020605@novell.com> <4A3E7E63.1070407@novell.com> <4A3FABD9.7080108@novell.com> <4A3FC2B1.4050107@novell.com> <20090622184139.GG15228@redhat.com> User-Agent: Alpine 1.10 (DEB 962 2008-03-14) X-GPG-FINGRPRINT: CFAE 5BEE FD36 F65E E640 56FE 0974 BF23 270F 474E X-GPG-PUBLIC_KEY: http://www.xmailserver.org/davidel.asc MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 983 Lines: 25 On Mon, 22 Jun 2009, Michael S. Tsirkin wrote: > On Mon, Jun 22, 2009 at 11:03:22AM -0700, Davide Libenzi wrote: > > In your case of kernel-to-kernel scenario, why would you need eventfd at > > all, if userspace role in that model is simply to create it? > > That's not 100% true. We have a mode where userspace is the producer > and/or consumer (migration mode) and we switch between that and > direct kernel-to-kernel communication. Then you'd need to ask yourself how to handle your complex case inside the KVM code, so that other eventfd users are not affected by the extra fat needed to handle your scenarios. Thing that seem to be continuosly tried. A file* based kernel-to-kernel interface is rather wrong IMO. - Davide -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/