From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751704AbcF3FNO (ORCPT ); Thu, 30 Jun 2016 01:13:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42301 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750709AbcF3FNM (ORCPT ); Thu, 30 Jun 2016 01:13:12 -0400 Subject: Re: [PATCH net-next V3 5/6] net: introduce NETDEV_CHANGE_TX_QUEUE_LEN To: John Fastabend , mst@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, davem@davemloft.net References: <1467258779-3539-1-git-send-email-jasowang@redhat.com> <1467258779-3539-6-git-send-email-jasowang@redhat.com> <5774A67B.1060802@gmail.com> Cc: kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, eric.dumazet@gmail.com, brouer@redhat.com From: Jason Wang Message-ID: <5774AA46.3090604@redhat.com> Date: Thu, 30 Jun 2016 13:12:38 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.8.0 MIME-Version: 1.0 In-Reply-To: <5774A67B.1060802@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Thu, 30 Jun 2016 05:12:44 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2016年06月30日 12:56, John Fastabend wrote: > On 16-06-29 08:52 PM, Jason Wang wrote: >> This patch introduces a new event - NETDEV_CHANGE_TX_QUEUE_LEN, this >> will be triggered when tx_queue_len. It could be used by net device >> who want to do some processing at that time. An example is tun who may >> want to resize tx array when tx_queue_len is changed. >> >> Signed-off-by: Jason Wang >> --- >> include/linux/netdevice.h | 1 + >> net/core/net-sysfs.c | 15 ++++++++++++++- >> 2 files changed, 15 insertions(+), 1 deletion(-) >> >> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h >> index e84d9d2..7dc2ec7 100644 >> --- a/include/linux/netdevice.h >> +++ b/include/linux/netdevice.h >> @@ -2237,6 +2237,7 @@ struct netdev_lag_lower_state_info { >> #define NETDEV_PRECHANGEUPPER 0x001A >> #define NETDEV_CHANGELOWERSTATE 0x001B >> #define NETDEV_UDP_TUNNEL_PUSH_INFO 0x001C >> +#define NETDEV_CHANGE_TX_QUEUE_LEN 0x001E >> >> int register_netdevice_notifier(struct notifier_block *nb); >> int unregister_netdevice_notifier(struct notifier_block *nb); >> diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c >> index 7a0b616..6e4f347 100644 >> --- a/net/core/net-sysfs.c >> +++ b/net/core/net-sysfs.c >> @@ -322,7 +322,20 @@ NETDEVICE_SHOW_RW(flags, fmt_hex); >> >> static int change_tx_queue_len(struct net_device *dev, unsigned long new_len) >> { >> - dev->tx_queue_len = new_len; >> + int res, orig_len = dev->tx_queue_len; >> + >> + if (new_len != orig_len) { >> + dev->tx_queue_len = new_len; >> + res = call_netdevice_notifiers(NETDEV_CHANGE_TX_QUEUE_LEN, dev); >> + res = notifier_to_errno(res); >> + if (res) { >> + netdev_err(dev, >> + "refused to change device tx_queue_len\n"); >> + dev->tx_queue_len = orig_len; >> + return -EFAULT; >> + } >> + } >> + >> return 0; >> } >> >> > Acked-by: John Fastabend > > Great timing I was just looking into this because I need it for the > qdisc side. > > It looks like this covers the sysfs change but the tx_queue_len can > also be changed via rtnetlink as well. So we need another patch for > that path right? > > if (tb[IFLA_TXQLEN]) { > unsigned long value = nla_get_u32(tb[IFLA_TXQLEN]); > > if (dev->tx_queue_len ^ value) > status |= DO_SETLINK_NOTIFY; > > dev->tx_queue_len = value; > } > > Thanks, > John > Right, will do this in next version. Thanks