Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752836Ab1EQCt2 (ORCPT ); Mon, 16 May 2011 22:49:28 -0400 Received: from ozlabs.org ([203.10.76.45]:56601 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752206Ab1EQCt0 (ORCPT ); Mon, 16 May 2011 22:49:26 -0400 From: Rusty Russell To: "Michael S. Tsirkin" Cc: linux-kernel@vger.kernel.org, Carsten Otte , Christian Borntraeger , linux390@de.ibm.com, Martin Schwidefsky , Heiko Carstens , Shirley Ma , lguest@lists.ozlabs.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, Krishna Kumar , Tom Lendacky , steved@us.ibm.com, habanero@linux.vnet.ibm.com Subject: Re: [PATCH 06/18] virtio_ring: avail event index interface In-Reply-To: <20110515124727.GA24932@redhat.com> References: <87aaewh5pg.fsf@rustcorp.com.au> <20110515124727.GA24932@redhat.com> User-Agent: Notmuch/0.5 (http://notmuchmail.org) Emacs/23.2.1 (i686-pc-linux-gnu) Date: Mon, 16 May 2011 15:53:19 +0930 Message-ID: <87k4drduzs.fsf@rustcorp.com.au> 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: 1473 Lines: 36 On Sun, 15 May 2011 15:47:27 +0300, "Michael S. Tsirkin" wrote: > On Mon, May 09, 2011 at 01:43:15PM +0930, Rusty Russell wrote: > > On Wed, 4 May 2011 23:51:19 +0300, "Michael S. Tsirkin" wrote: > > > #define VIRTIO_RING_F_USED_EVENT_IDX 29 > > > +/* The Host publishes the avail index for which it expects a kick > > > + * at the end of the used ring. Guest should ignore the used->flags field. */ > > > +#define VIRTIO_RING_F_AVAIL_EVENT_IDX 32 > > > > Are you really sure we want to separate the two? Seems a little simpler > > to have one bit to mean "we're publishing our threshold". For someone > > implementing this from scratch, it's a little simpler. > > > > Or are there cases where the old style makes more sense? > > > > Thanks, > > Rusty. > > Hmm, it makes debugging easier as each side can disable > publishing separately - I used it all the time when I saw > e.g. networking stuck to guess whether I need to investigate the > interrupt or the exit handling. > > But I'm not hung up on this. > > Let me know pls. If we combine them into one, then these patches no longer depend on the feature bit expansion, which is worthwhile (though I'll take both). Thanks, Rusty. -- 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/