From: Gao feng <gaofeng@cn.fujitsu.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Miller <davem@davemloft.net>,
netdev@vger.kernel.org, maheshb@google.com, therbert@google.com,
ebiederm@xmission.com
Subject: Re: [PATCH net-next v3] net: remove delay at device dismantle
Date: Thu, 23 Aug 2012 12:33:03 +0800 [thread overview]
Message-ID: <5035B27F.9060002@cn.fujitsu.com> (raw)
In-Reply-To: <1345691986.5904.40.camel@edumazet-glaptop>
于 2012年08月23日 11:19, Eric Dumazet 写道:
> From: Eric Dumazet <edumazet@google.com>
>
> I noticed extra one second delay in device dismantle, tracked down to
> a call to dst_dev_event() while some call_rcu() are still in RCU queues.
>
> These call_rcu() were posted by rt_free(struct rtable *rt) calls.
>
> We then wait a little (but one second) in netdev_wait_allrefs() before
> kicking again NETDEV_UNREGISTER.
>
> As the call_rcu() are now completed, dst_dev_event() can do the needed
> device swap on busy dst.
>
> To solve this problem, add a new NETDEV_UNREGISTER_FINAL, called
> after a rcu_barrier(), but outside of RTNL lock.
>
> Use NETDEV_UNREGISTER_FINAL with care !
>
> Change dst_dev_event() handler to react to NETDEV_UNREGISTER_FINAL
>
> Also remove NETDEV_UNREGISTER_BATCH, as its not used anymore after
> IP cache removal.
>
> With help from Gao feng
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: Tom Herbert <therbert@google.com>
> Cc: Mahesh Bandewar <maheshb@google.com>
> Cc: "Eric W. Biederman" <ebiederm@xmission.com>
> Cc: Gao feng <gaofeng@cn.fujitsu.com>
looks good to me, the lockdep warning message disappeared.
next prev parent reply other threads:[~2012-08-23 4:32 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-23 3:19 [PATCH net-next v3] net: remove delay at device dismantle Eric Dumazet
2012-08-23 4:33 ` Gao feng [this message]
2012-08-23 4:50 ` David Miller
2012-08-23 6:34 ` Eric W. Biederman
2012-08-23 7:00 ` Eric Dumazet
2012-08-23 18:21 ` Ben Hutchings
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=5035B27F.9060002@cn.fujitsu.com \
--to=gaofeng@cn.fujitsu.com \
--cc=davem@davemloft.net \
--cc=ebiederm@xmission.com \
--cc=eric.dumazet@gmail.com \
--cc=maheshb@google.com \
--cc=netdev@vger.kernel.org \
--cc=therbert@google.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.