From: John Fastabend <john.fastabend@gmail.com>
To: xiyou.wangcong@gmail.com, jhs@mojatatu.com,
alexei.starovoitov@gmail.com, eric.dumazet@gmail.com,
brouer@redhat.com
Cc: john.r.fastabend@intel.com, netdev@vger.kernel.org, davem@davemloft.net
Subject: Re: [RFC PATCH 10/13] net: sched: lockless support for netif_schedule
Date: Wed, 17 Aug 2016 12:46:29 -0700 [thread overview]
Message-ID: <57B4BF15.2000109@gmail.com> (raw)
In-Reply-To: <20160817193738.27032.25592.stgit@john-Precision-Tower-5810>
On 16-08-17 12:37 PM, John Fastabend wrote:
> netif_schedule uses a bit QDISC_STATE_SCHED to tell the qdisc layer
> if a run of the qdisc has been scheduler. This is important when
> tearing down qdisc instances. We can rcu_free an instance for example
> if its possible that we might have outstanding references to it.
>
> Perhaps more importantly in the per cpu lockless case we need to
> schedule a run of the qdisc on all qdiscs that are enqueu'ing packets
> and hitting the gso_skb requeue logic or else the skb may get stuck
> on the gso_skb queue without anything to finish the xmit.
>
> This patch uses a reference counter instead of a bit to account for
> the multiple CPUs.
> ---
oops the commit message is incorrect here it actually uses a per cpu
state bitmask to track this.
next prev parent reply other threads:[~2016-08-17 19:46 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-17 19:33 [RFC PATCH 00/13] Series short description John Fastabend
2016-08-17 19:33 ` [RFC PATCH 01/13] net: sched: allow qdiscs to handle locking John Fastabend
2016-08-17 22:33 ` Eric Dumazet
2016-08-17 22:49 ` John Fastabend
2016-08-17 22:34 ` Eric Dumazet
2016-08-17 22:48 ` John Fastabend
2016-08-17 19:34 ` [RFC PATCH 02/13] net: sched: qdisc_qlen for per cpu logic John Fastabend
2016-08-17 19:34 ` [RFC PATCH 03/13] net: sched: provide per cpu qstat helpers John Fastabend
2016-08-17 19:35 ` [RFC PATCH 04/13] net: sched: provide atomic qlen helpers for bypass case John Fastabend
2016-08-17 19:35 ` [RFC PATCH 05/13] net: sched: a dflt qdisc may be used with per cpu stats John Fastabend
2016-08-17 19:35 ` [RFC PATCH 06/13] net: sched: per cpu gso handlers John Fastabend
2016-08-17 19:36 ` [RFC PATCH 07/13] net: sched: support qdisc_reset on NOLOCK qdisc John Fastabend
2016-08-17 22:53 ` Eric Dumazet
2016-08-17 22:59 ` John Fastabend
2016-08-17 19:36 ` [RFC PATCH 08/13] net: sched: support skb_bad_tx with lockless qdisc John Fastabend
2016-08-17 22:58 ` Eric Dumazet
2016-08-17 23:00 ` John Fastabend
2016-08-23 20:11 ` John Fastabend
2016-08-17 19:37 ` [RFC PATCH 09/13] net: sched: helper to sum qlen John Fastabend
2016-08-17 19:37 ` [RFC PATCH 10/13] net: sched: lockless support for netif_schedule John Fastabend
2016-08-17 19:46 ` John Fastabend [this message]
2016-08-17 23:01 ` Eric Dumazet
2016-08-17 23:17 ` John Fastabend
2016-08-17 23:33 ` Eric Dumazet
2016-08-17 19:38 ` [RFC PATCH 11/13] net: sched: pfifo_fast use alf_queue John Fastabend
2016-08-19 10:13 ` Jesper Dangaard Brouer
2016-08-19 15:44 ` John Fastabend
2016-08-17 19:38 ` [RFC PATCH 12/13] net: sched: add support for TCQ_F_NOLOCK subqueues to sch_mq John Fastabend
2016-08-17 19:49 ` John Fastabend
2016-08-17 23:04 ` Eric Dumazet
2016-08-17 23:18 ` John Fastabend
2016-08-17 19:39 ` [RFC PATCH 13/13] net: sched: add support for TCQ_F_NOLOCK subqueues to sch_mqprio John Fastabend
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