From: Cong Wang <xiyou.wangcong@gmail.com>
To: Petr Machata <petrm@mellanox.com>
Cc: Linux Kernel Network Developers <netdev@vger.kernel.org>,
David Miller <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Eric Dumazet <eric.dumazet@gmail.com>,
Jiri Pirko <jiri@mellanox.com>,
Ido Schimmel <idosch@mellanox.com>
Subject: Re: [PATCH net-next v1 1/5] net: sched: Pass root lock to Qdisc_ops.enqueue
Date: Mon, 6 Jul 2020 12:21:33 -0700 [thread overview]
Message-ID: <CAM_iQpUEAt_0Kr1vVfRrpMPz+2arpLA5g4yfWCLe2fhbMTrH7w@mail.gmail.com> (raw)
In-Reply-To: <643ef0859371d3bf6280f5014d668fb18b3b6d85.1593209494.git.petrm@mellanox.com>
On Fri, Jun 26, 2020 at 3:46 PM Petr Machata <petrm@mellanox.com> wrote:
>
> A following patch introduces qevents, points in qdisc algorithm where
> packet can be processed by user-defined filters. Should this processing
> lead to a situation where a new packet is to be enqueued on the same port,
> holding the root lock would lead to deadlocks. To solve the issue, qevent
> handler needs to unlock and relock the root lock when necessary.
>
> To that end, add the root lock argument to the qdisc op enqueue, and
> propagate throughout.
Hmm, but why do you pass root lock down to each ->enqueue()?
You can find root lock with sch_tree_lock() (or qdisc_lock() if you don't
care about hierarchy), and you already have qdisc as a parameter of
tcf_qevent_handle().
Thanks.
next prev parent reply other threads:[~2020-07-06 19:21 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-26 22:45 [PATCH net-next v1 0/5] TC: Introduce qevents Petr Machata
2020-06-26 22:45 ` [PATCH net-next v1 1/5] net: sched: Pass root lock to Qdisc_ops.enqueue Petr Machata
2020-07-06 19:21 ` Cong Wang [this message]
2020-07-07 15:25 ` Petr Machata
2020-07-07 19:41 ` Cong Wang
2020-06-26 22:45 ` [PATCH net-next v1 2/5] net: sched: Introduce helpers for qevent blocks Petr Machata
2020-07-06 19:48 ` Cong Wang
2020-07-07 15:22 ` Petr Machata
2020-07-07 19:13 ` Cong Wang
2020-07-08 12:35 ` Petr Machata
2020-07-08 16:21 ` Petr Machata
2020-07-08 19:09 ` Cong Wang
2020-07-08 19:04 ` Cong Wang
2020-07-08 21:04 ` Petr Machata
2020-07-09 0:13 ` Petr Machata
2020-07-09 19:37 ` Cong Wang
2020-07-10 14:40 ` Petr Machata
2020-07-14 2:51 ` Cong Wang
2020-07-14 9:12 ` Petr Machata
2020-07-07 19:48 ` Cong Wang
2020-07-08 9:19 ` Petr Machata
2020-06-26 22:45 ` [PATCH net-next v1 3/5] net: sched: sch_red: Split init and change callbacks Petr Machata
2020-06-26 22:45 ` [PATCH net-next v1 4/5] net: sched: sch_red: Add qevents "early_drop" and "mark" Petr Machata
2020-06-26 22:45 ` [PATCH net-next v1 5/5] selftests: forwarding: Add a RED test for SW datapath Petr Machata
2020-06-26 22:45 ` [PATCH iproute2-next v1 1/4] uapi: pkt_sched: Add two new RED attributes Petr Machata
2020-06-26 22:45 ` [PATCH iproute2-next v1 2/4] tc: Add helpers to support qevent handling Petr Machata
2020-06-26 22:45 ` [PATCH iproute2-next v1 3/4] man: tc: Describe qevents Petr Machata
2020-06-26 22:45 ` [PATCH iproute2-next v1 4/4] tc: q_red: Add support for qevents "mark" and "early_drop" Petr Machata
2020-06-26 22:56 ` [PATCH net-next v1 0/5] TC: Introduce qevents Stephen Hemminger
2020-06-29 13:21 ` Petr Machata
2020-06-30 0:15 ` David Miller
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