From: Eric Dumazet <eric.dumazet@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org, ebiederm@xmission.com
Subject: Re: [RFC] NETDEV_UNREGISTER_BATCH seems unused nowaday ?
Date: Fri, 10 Aug 2012 13:06:49 +0200 [thread overview]
Message-ID: <1344596809.31104.2358.camel@edumazet-glaptop> (raw)
In-Reply-To: <20120810.034211.994338127277150687.davem@davemloft.net>
On Fri, 2012-08-10 at 03:42 -0700, David Miller wrote:
> From: Eric Dumazet <eric.dumazet@gmail.com>
> Date: Fri, 10 Aug 2012 11:27:04 +0200
>
> > NETDEV_UNREGISTER_BATCH seems unused we can probably remove it.
>
> Indeed, the routing cache was the final real user.
>
> > I am tracking a device refcount issue, delaying net device dismantle by
> > 1 second in netdev_wait_allrefs()
> >
> > I guess we need to add a notifier called _after_ the final
> > synchronize_net() in rollback_registered_many()
>
> It's essentially caused by DST_GC_INC, right?
No, we in fact need a rcu_barrier(), then another call to
dst_dev_event().
rcu_barrier() is needed so that in-flight call_rcu() of routes (from
rt_free()) are completed. Or else we miss these dst in the
dst_dev_event().
I have a working patch, adding the rcu_barrier() and one additional
NETDEV_UNREGISTER_FINAL event.
next prev parent reply other threads:[~2012-08-10 11:06 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-10 9:27 [RFC] NETDEV_UNREGISTER_BATCH seems unused nowaday ? Eric Dumazet
2012-08-10 10:42 ` David Miller
2012-08-10 11:06 ` Eric Dumazet [this message]
2012-08-10 14:45 ` Eric W. Biederman
2012-08-10 15:01 ` Eric Dumazet
2012-08-10 17:55 ` Paul E. McKenney
2012-08-10 14:46 ` [PATCH] net: remove delay at device dismantle Eric Dumazet
2012-08-10 15:42 ` [PATCH net-next v2] " Eric Dumazet
2012-08-11 5:54 ` Eric Dumazet
2012-08-11 5:57 ` David Miller
2012-08-23 2:18 ` David Miller
2012-08-23 2:25 ` Gao feng
2012-08-23 2:51 ` David Miller
2012-08-23 2:58 ` Eric Dumazet
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