From patchwork Mon Dec 20 12:38:38 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tonghao Zhang X-Patchwork-Id: 12687829 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4ADF3C433F5 for ; Mon, 20 Dec 2021 12:39:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230459AbhLTMi7 (ORCPT ); Mon, 20 Dec 2021 07:38:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60176 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229820AbhLTMi6 (ORCPT ); Mon, 20 Dec 2021 07:38:58 -0500 Received: from mail-io1-xd2a.google.com (mail-io1-xd2a.google.com [IPv6:2607:f8b0:4864:20::d2a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A70A8C06173E for ; Mon, 20 Dec 2021 04:38:58 -0800 (PST) Received: by mail-io1-xd2a.google.com with SMTP id p23so13024801iod.7 for ; Mon, 20 Dec 2021 04:38:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=KzRnx4QbBFrHXeIFuSoQV6bzYSSMU3bSDt0hCmxu2v0=; b=JXO/ZRifW2Kf/X/YNYQ2AS1i43NVS4Rpg1oaYMnqJgGRBOQfdClwZCPESRXiu4y+Lv jKOA49TE0XfjtnaJAq7fxcAGaJs48o58Kyjf3D1KU7wR0riaNFxYiasQkLX89OB5giFR 6hJkMVxJ7oFiClPyZQ1M+R93L4hxBUmRmlOjvh7KnwIwN9CTIxMRfcvCyo7C8t20e4fW R6lV6fc8qEnraa6KsRFGtNdC4WzGoCdkZJG5NAlCe8LznbhjyBrjq6qaXsAswJ5Zff2V 1VvWv6OWhawqlPivwgiB38C/LXOGShntal/ji5Wdr+tXkXbWuZ0GNWD+palZG4vSJPe0 A1xw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=KzRnx4QbBFrHXeIFuSoQV6bzYSSMU3bSDt0hCmxu2v0=; b=3I1hbjmK+YyWKcgSh2ENs8kbzv/D1TWQuo5jaCZgVEfeo9HUCYiBkLhFHcu41EEDUe OCy90FffEBxVaYyFmhEkFoeP9BV5c8n8A+u0jQXKLkx9/OcIcBrX+eA+XWV7APgUxwH9 Zf7gLIsxLibEQ6sGoqrZvx/VP4Ga7kbXJOKhaGP+sHnfsX0M+x4bqsh79vgJeEAUnjPH 6vMXPnZL4FTHcSmFVDJb8POhyyjHWC5FYkEgYhzbWN3U1ZsaHoG1JIldloMoV5aE/7mt uz7PHDI5MVJ5dZCAwcSptEM7U2HUDUAmkXyKdMtCOS4aamZlPxprqSjl5dH2+v0NwLE6 UnhQ== X-Gm-Message-State: AOAM533FBCBbIW9RhmMvUtp+j7PVYluL2HD94ULXBT+QfqzOPFQATxbn GvLsOqG2nuRQTdjY2tP58KGErfedBsj0vg== X-Google-Smtp-Source: ABdhPJyQi0BTZPD+g2J1mMO1z8XthxJKNuo2gxTwZskYJGtHW0En2tuubRsbo6LOuYb3xY4U5hNhBw== X-Received: by 2002:a05:6602:2c09:: with SMTP id w9mr4392678iov.89.1640003937404; Mon, 20 Dec 2021 04:38:57 -0800 (PST) Received: from bogon.xiaojukeji.com ([111.201.150.233]) by smtp.gmail.com with ESMTPSA id h13sm7256414ilj.59.2021.12.20.04.38.51 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 20 Dec 2021 04:38:56 -0800 (PST) From: xiangxia.m.yue@gmail.com To: netdev@vger.kernel.org Cc: Tonghao Zhang , Jamal Hadi Salim , Cong Wang , Jiri Pirko , "David S. Miller" , Jakub Kicinski , Jonathan Lemon , Eric Dumazet , Alexander Lobakin , Paolo Abeni , Talal Ahmad , Kevin Hao , Ilias Apalodimas , Kees Cook , Kumar Kartikeya Dwivedi , Antoine Tenart , Wei Wang , Arnd Bergmann Subject: [net-next v5 1/2] net: sched: use queue_mapping to pick tx queue Date: Mon, 20 Dec 2021 20:38:38 +0800 Message-Id: <20211220123839.54664-2-xiangxia.m.yue@gmail.com> X-Mailer: git-send-email 2.30.1 (Apple Git-130) In-Reply-To: <20211220123839.54664-1-xiangxia.m.yue@gmail.com> References: <20211220123839.54664-1-xiangxia.m.yue@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org From: Tonghao Zhang This patch fixes issue: * If we install tc filters with act_skbedit in clsact hook. It doesn't work, because netdev_core_pick_tx() overwrites queue_mapping. $ tc filter ... action skbedit queue_mapping 1 And this patch is useful: * We can use FQ + EDT to implement efficient policies. Tx queues are picked by xps, ndo_select_queue of netdev driver, or skb hash in netdev_core_pick_tx(). In fact, the netdev driver, and skb hash are _not_ under control. xps uses the CPUs map to select Tx queues, but we can't figure out which task_struct of pod/containter running on this cpu in most case. We can use clsact filters to classify one pod/container traffic to one Tx queue. Why ? In containter networking environment, there are two kinds of pod/ containter/net-namespace. One kind (e.g. P1, P2), the high throughput is key in these applications. But avoid running out of network resource, the outbound traffic of these pods is limited, using or sharing one dedicated Tx queues assigned HTB/TBF/FQ Qdisc. Other kind of pods (e.g. Pn), the low latency of data access is key. And the traffic is not limited. Pods use or share other dedicated Tx queues assigned FIFO Qdisc. This choice provides two benefits. First, contention on the HTB/FQ Qdisc lock is significantly reduced since fewer CPUs contend for the same queue. More importantly, Qdisc contention can be eliminated completely if each CPU has its own FIFO Qdisc for the second kind of pods. There must be a mechanism in place to support classifying traffic based on pods/container to different Tx queues. Note that clsact is outside of Qdisc while Qdisc can run a classifier to select a sub-queue under the lock. In general recording the decision in the skb seems a little heavy handed. This patch introduces a per-CPU variable, suggested by Eric. The xmit.skip_txqueue flag is firstly cleared in __dev_queue_xmit(). - Tx Qdisc may install that skbedit actions, then xmit.skip_txqueue flag is set in qdisc->enqueue() though tx queue has been selected in netdev_tx_queue_mapping() or netdev_core_pick_tx(). That flag is cleared firstly in __dev_queue_xmit(), is useful: - Avoid picking Tx queue with netdev_tx_queue_mapping() in next netdev in such case: eth0 macvlan - eth0.3 vlan - eth0 ixgbe-phy: For example, eth0, macvlan in pod, which root Qdisc install skbedit queue_mapping, send packets to eth0.3, vlan in host. In __dev_queue_xmit() of eth0.3, clear the flag, does not select tx queue according to skb->queue_mapping because there is no filters in clsact or tx Qdisc of this netdev. Same action taked in eth0, ixgbe in Host. - Avoid picking Tx queue for next packet. If we set xmit.skip_txqueue in tx Qdisc (qdisc->enqueue()), the proper way to clear it is clearing it in __dev_queue_xmit when processing next packets. +----+ +----+ +----+ | P1 | | P2 | | Pn | +----+ +----+ +----+ | | | +-----------+-----------+ | | clsact/skbedit | MQ v +-----------+-----------+ | q0 | q1 | qn v v v HTB/FQ HTB/FQ ... FIFO Cc: Jamal Hadi Salim Cc: Cong Wang Cc: Jiri Pirko Cc: "David S. Miller" Cc: Jakub Kicinski Cc: Jonathan Lemon Cc: Eric Dumazet Cc: Alexander Lobakin Cc: Paolo Abeni Cc: Talal Ahmad Cc: Kevin Hao Cc: Ilias Apalodimas Cc: Kees Cook Cc: Kumar Kartikeya Dwivedi Cc: Antoine Tenart Cc: Wei Wang Cc: Arnd Bergmann Suggested-by: Eric Dumazet Signed-off-by: Tonghao Zhang --- include/linux/netdevice.h | 19 +++++++++++++++++++ net/core/dev.c | 7 ++++++- net/sched/act_skbedit.c | 4 +++- 3 files changed, 28 insertions(+), 2 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 8b0bdeb4734e..8d02dafb32ba 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -3009,6 +3009,7 @@ struct softnet_data { /* written and read only by owning cpu: */ struct { u16 recursion; + u8 skip_txqueue; u8 more; } xmit; #ifdef CONFIG_RPS @@ -4696,6 +4697,24 @@ static inline netdev_tx_t netdev_start_xmit(struct sk_buff *skb, struct net_devi return rc; } +static inline void netdev_xmit_skip_txqueue(bool skip) +{ + __this_cpu_write(softnet_data.xmit.skip_txqueue, skip); +} + +static inline bool netdev_xmit_txqueue_skipped(void) +{ + return __this_cpu_read(softnet_data.xmit.skip_txqueue); +} + +static inline struct netdev_queue * +netdev_tx_queue_mapping(struct net_device *dev, struct sk_buff *skb) +{ + int qm = skb_get_queue_mapping(skb); + + return netdev_get_tx_queue(dev, netdev_cap_txqueue(dev, qm)); +} + int netdev_class_create_file_ns(const struct class_attribute *class_attr, const void *ns); void netdev_class_remove_file_ns(const struct class_attribute *class_attr, diff --git a/net/core/dev.c b/net/core/dev.c index a855e41bbe39..e3f548c54dda 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4048,6 +4048,7 @@ static int __dev_queue_xmit(struct sk_buff *skb, struct net_device *sb_dev) skb_update_prio(skb); qdisc_pkt_len_init(skb); + netdev_xmit_skip_txqueue(false); #ifdef CONFIG_NET_CLS_ACT skb->tc_at_ingress = 0; #endif @@ -4073,7 +4074,11 @@ static int __dev_queue_xmit(struct sk_buff *skb, struct net_device *sb_dev) else skb_dst_force(skb); - txq = netdev_core_pick_tx(dev, skb, sb_dev); + if (netdev_xmit_txqueue_skipped()) + txq = netdev_tx_queue_mapping(dev, skb); + else + txq = netdev_core_pick_tx(dev, skb, sb_dev); + q = rcu_dereference_bh(txq->qdisc); trace_net_dev_queue(skb); diff --git a/net/sched/act_skbedit.c b/net/sched/act_skbedit.c index ceba11b198bb..48504ed3b280 100644 --- a/net/sched/act_skbedit.c +++ b/net/sched/act_skbedit.c @@ -58,8 +58,10 @@ static int tcf_skbedit_act(struct sk_buff *skb, const struct tc_action *a, } } if (params->flags & SKBEDIT_F_QUEUE_MAPPING && - skb->dev->real_num_tx_queues > params->queue_mapping) + skb->dev->real_num_tx_queues > params->queue_mapping) { + netdev_xmit_skip_txqueue(true); skb_set_queue_mapping(skb, params->queue_mapping); + } if (params->flags & SKBEDIT_F_MARK) { skb->mark &= ~params->mask; skb->mark |= params->mark & params->mask;