From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754258AbaDNBkW (ORCPT ); Sun, 13 Apr 2014 21:40:22 -0400 Received: from shards.monkeyblade.net ([149.20.54.216]:49110 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754171AbaDNBkR (ORCPT ); Sun, 13 Apr 2014 21:40:17 -0400 Date: Sun, 13 Apr 2014 21:40:04 -0400 (EDT) Message-Id: <20140413.214004.1087903132047842986.davem@davemloft.net> To: sgalgano@adjacentlink.com Cc: mst@redhat.com, jasowang@redhat.com, xemul@parallels.com, wuzhy@linux.vnet.ibm.com, therbert@google.com, yamato@redhat.com, richardcochran@gmail.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Brian.Adamson@nrl.navy.mil, jgiovatto@adjacentlink.com Subject: Re: [PATCH v2] tuntap: add flow control to support back pressure From: David Miller In-Reply-To: <534B3A33.9090401@adjacentlink.com> References: <5347487B.4040608@adjacentlink.com> <20140413141745.GB17839@redhat.com> <534B3A33.9090401@adjacentlink.com> X-Mailer: Mew version 6.5 on Emacs 24.3 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.7 (shards.monkeyblade.net [149.20.54.216]); Sun, 13 Apr 2014 18:40:17 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Steven Galgano Date: Sun, 13 Apr 2014 21:30:27 -0400 > Added optional per queue flow control support using IFF_FLOW_CONTROL. When the IFF_FLOW_CONTROL TUNSETIFF flag is specified it will set a per queue flag to indicate that the queue should be stopped using netif_tx_stop_queue(), rather than discarding frames once full. After reading a frame from the respective stopped queue, a netif_tx_wake_queue() is issued to signal resource availability. > > The per queue TUN_FLOW_CONTROL flag is stored in struct tun_file. This provides the flexibility to enable flow control on all, none or some queues when using IFF_MULTI_QUEUE. When not using IFF_MULTI_QUEUE, IFF_FLOW_CONTROL will apply to the single queue. No changes were made to the default drop frame policy. > > This change adds support for back pressure use cases. > > Reported-by: Brian Adamson > Tested-by: Joseph Giovatto > Signed-off-by: Steven Galgano Please format your commit messages to ~80 columns of text. It won't be automatically formatted by GIT and in fact it looks ugly with all the wrapping in text based tools.