From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Fastabend Subject: [net-next PATCH v3 15/15] net: sched: drop ingress qdisc lock Date: Mon, 08 Sep 2014 23:01:14 -0700 Message-ID: <20140909060112.2071.33861.stgit@nitbit.x32> References: <20140909055221.2071.99671.stgit@nitbit.x32> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, paulmck@linux.vnet.ibm.com, brouer@redhat.com To: xiyou.wangcong@gmail.com, davem@davemloft.net, eric.dumazet@gmail.com, jhs@mojatatu.com Return-path: Received: from mail-oa0-f52.google.com ([209.85.219.52]:40033 "EHLO mail-oa0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750827AbaIIGBe (ORCPT ); Tue, 9 Sep 2014 02:01:34 -0400 Received: by mail-oa0-f52.google.com with SMTP id g18so2425696oah.25 for ; Mon, 08 Sep 2014 23:01:34 -0700 (PDT) In-Reply-To: <20140909055221.2071.99671.stgit@nitbit.x32> Sender: netdev-owner@vger.kernel.org List-ID: After the previous patches to make the filters RCU safe and support per cpu counters we can drop the qdisc lock around the ingress qdisc hook. This is possible because the ingress qdisc is a very basic qdisc and only updates stats and runs tc_classify. Its the simplest qdiscs we have. In order for the per-cpu counters to get invoked the ingress qdisc must set the LLQDISC flag. We could use per-cpu counters on all counters but it is only necessary when the qdisc lock is not held. Signed-off-by: John Fastabend --- net/core/dev.c | 2 -- net/sched/sch_ingress.c | 6 ++++++ 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 1e25640..b474577 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3481,10 +3481,8 @@ static int ing_filter(struct sk_buff *skb, struct netdev_queue *rxq) q = rcu_dereference(rxq->qdisc); if (q != &noop_qdisc) { - spin_lock(qdisc_lock(q)); if (likely(!test_bit(__QDISC_STATE_DEACTIVATED, &q->state))) result = qdisc_enqueue_root(skb, q); - spin_unlock(qdisc_lock(q)); } return result; diff --git a/net/sched/sch_ingress.c b/net/sched/sch_ingress.c index 88a6289..57ea680 100644 --- a/net/sched/sch_ingress.c +++ b/net/sched/sch_ingress.c @@ -89,6 +89,11 @@ static int ingress_enqueue(struct sk_buff *skb, struct Qdisc *sch) } /* ------------------------------------------------------------- */ +static int ingress_init(struct Qdisc *sch, struct nlattr *opt) +{ + sch->flags |= TCQ_F_LLQDISC; + return 0; +} static void ingress_destroy(struct Qdisc *sch) { @@ -122,6 +127,7 @@ static const struct Qdisc_class_ops ingress_class_ops = { }; static struct Qdisc_ops ingress_qdisc_ops __read_mostly = { + .init = ingress_init, .cl_ops = &ingress_class_ops, .id = "ingress", .priv_size = sizeof(struct ingress_qdisc_data),