From: Petr Machata <petrm@mellanox.com>
To: Cong Wang <xiyou.wangcong@gmail.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 2/5] net: sched: Introduce helpers for qevent blocks
Date: Wed, 08 Jul 2020 23:04:36 +0200 [thread overview]
Message-ID: <87wo3dhg63.fsf@mellanox.com> (raw)
In-Reply-To: <CAM_iQpVs_OEBw54qMhn7Tx6_YAGh5PMSApj=RrO0j6ThSXpkcg@mail.gmail.com>
Cong Wang <xiyou.wangcong@gmail.com> writes:
> On Wed, Jul 8, 2020 at 5:35 AM Petr Machata <petrm@mellanox.com> wrote:
>> Do you have another solution in mind here? I think the deadlock (in both
>> classification and qevents) is an issue, but really don't know how to
>> avoid it except by dropping the lock.
>
> Ideally we should only take the lock once, but it clearly requires some
> work to teach the dev_queue_xmit() in act_mirred not to acquire it again.
act_mirred does not acquire it though. The egress path does. And the
packet can traverse several mirred instances on several devices before
it gets to the deadlock. Currently I don't see a way to give the egress
path a way to know that the lock is already taken.
I'll think about it some more. For now I will at least fix the lack of
locking.
next prev parent reply other threads:[~2020-07-08 21:04 UTC|newest]
Thread overview: 32+ 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
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 [this message]
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
-- strict thread matches above, loose matches on Subject: below --
2020-06-27 21:06 [PATCH net-next v1 2/5] net: sched: Introduce helpers for qevent blocks kernel test robot
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87wo3dhg63.fsf@mellanox.com \
--to=petrm@mellanox.com \
--cc=davem@davemloft.net \
--cc=eric.dumazet@gmail.com \
--cc=idosch@mellanox.com \
--cc=jiri@mellanox.com \
--cc=kuba@kernel.org \
--cc=netdev@vger.kernel.org \
--cc=xiyou.wangcong@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.