From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:33286) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TsJzp-0002Bi-9z for qemu-devel@nongnu.org; Mon, 07 Jan 2013 16:12:40 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TsJzl-0006wU-Rg for qemu-devel@nongnu.org; Mon, 07 Jan 2013 16:12:37 -0500 Received: from mx1.redhat.com ([209.132.183.28]:1177) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TsJzl-0006wI-Jl for qemu-devel@nongnu.org; Mon, 07 Jan 2013 16:12:33 -0500 Date: Mon, 7 Jan 2013 23:16:11 +0200 From: "Michael S. Tsirkin" Message-ID: <20130107211611.GE8679@redhat.com> References: <1357584074-10852-1-git-send-email-fred.konrad@greensocs.com> <1357584074-10852-20-git-send-email-fred.konrad@greensocs.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1357584074-10852-20-git-send-email-fred.konrad@greensocs.com> Subject: Re: [Qemu-devel] [PATCH 19/61] virtio-net : cleanup : use QOM cast. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: fred.konrad@greensocs.com Cc: kwolf@redhat.com, peter.maydell@linaro.org, aliguori@us.ibm.com, e.voevodin@samsung.com, mark.burton@greensocs.com, qemu-devel@nongnu.org, agraf@suse.de, amit.shah@redhat.com, aneesh.kumar@linux.vnet.ibm.com, stefanha@redhat.com, cornelia.huck@de.ibm.com, pbonzini@redhat.com, afaerber@suse.de On Mon, Jan 07, 2013 at 07:40:32PM +0100, fred.konrad@greensocs.com wrote: > @@ -130,7 +124,9 @@ static void virtio_net_set_status(struct VirtIODevice *vdev, uint8_t status) > > static void virtio_net_set_link_status(NetClientState *nc) > { > - VirtIONet *n = DO_UPCAST(NICState, nc, nc)->opaque; > + void *opaque = DO_UPCAST(NICState, nc, nc)->opaque; > + VirtIONet *n = VIRTIO_NET(opaque); > + VirtIODevice *vdev = VIRTIO_DEVICE(n); > uint16_t old_status = n->status; > > if (nc->link_down) I note this adds more pointer chasing due to runtime casts on data path operations. Can well be trivial but this really needs to be verified with a performance test. Was this done? Same comment applies to block. An alternative is to add _fast casts without runtime checks. -- MST