From: David Miller <davem@davemloft.net>
To: eric.dumazet@gmail.com
Cc: greearb@candelatech.com, netdev@vger.kernel.org, kaber@trash.net
Subject: Re: [PATCH net-next-2.6] net: avoid synchronize_rcu() in dev_deactivate_many
Date: Sun, 22 May 2011 21:02:55 -0400 (EDT) [thread overview]
Message-ID: <20110522.210255.1260763671419618526.davem@davemloft.net> (raw)
In-Reply-To: <1305884529.3173.11.camel@edumazet-laptop>
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Fri, 20 May 2011 11:42:09 +0200
> dev_deactivate_many() issues one synchronize_rcu() call after qdiscs set
> to noop_qdisc.
>
> This call is here to make sure they are no outstanding qdisc-less
> dev_queue_xmit calls before returning to caller.
>
> But in dismantle phase, we dont have to wait, because we wont activate
> again the device, and we are going to wait one rcu grace period later in
> rollback_registered_many().
>
> After this patch, device dismantle uses one synchronize_net() and one
> rcu_barrier() call only, so we have a ~30% speedup and a smaller RTNL
> latency.
>
> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
> CC: Patrick McHardy <kaber@trash.net>,
> CC: Ben Greear <greearb@candelatech.com>
Applied.
prev parent reply other threads:[~2011-05-23 1:04 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-20 9:42 [PATCH net-next-2.6] net: avoid synchronize_rcu() in dev_deactivate_many Eric Dumazet
2011-05-23 1:02 ` David Miller [this message]
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