From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH RFC 2/2] tun: don't set a default qdisc Date: Wed, 13 Apr 2016 13:26:51 +0300 Message-ID: <20160413132411-mutt-send-email-mst@redhat.com> References: <1a216fb6cade7dcd7d2c1d4ce113a1ee6e3fdeb6.1460393493.git.pabeni@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org, "David S. Miller" , Hannes Frederic Sowa , "Eric W. Biederman" , Greg Kurz , Jason Wang To: Paolo Abeni Return-path: Received: from mx1.redhat.com ([209.132.183.28]:37003 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965432AbcDMK0z (ORCPT ); Wed, 13 Apr 2016 06:26:55 -0400 Content-Disposition: inline In-Reply-To: <1a216fb6cade7dcd7d2c1d4ce113a1ee6e3fdeb6.1460393493.git.pabeni@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Apr 13, 2016 at 11:04:47AM +0200, Paolo Abeni wrote: > This patch disables the default qdisc by explicitly setting the > IFF_NO_QUEUE private flag so that now the tun xmit path do not > require any lock by default. > > The default qdisc was first removed as a side effect of commit > f84bb1eac027 ("net: fix IFF_NO_QUEUE for drivers using alloc_netdev") > and recently restored with commit 016adb7260f4 ("tuntap: restore default qdisc") > > Signed-off-by: Paolo Abeni I wonder about this back and forth. Jason, do you see a workload where the default qdisc is preferable? > --- > drivers/net/tun.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index 42992dc..0a0b63c 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -1081,6 +1081,7 @@ static void tun_net_init(struct net_device *dev) > > break; > } > + dev->priv_flags |= IFF_NO_QUEUE; > } > > /* Character device part */ > -- > 1.8.3.1