From: David Miller <davem@davemloft.net>
To: shemminger@vyatta.com
Cc: eric.dumazet@gmail.com, kaber@trash.net, netdev@vger.kernel.org,
remi.denis-courmont@nokia.com
Subject: Re: [PATCH net-next-2.6] net: dont hold rtnl mutex during netlink dump callbacks
Date: Mon, 02 May 2011 15:27:33 -0700 (PDT) [thread overview]
Message-ID: <20110502.152733.48516094.davem@davemloft.net> (raw)
In-Reply-To: <20110428084337.6b54603e@nehalam>
From: Stephen Hemminger <shemminger@vyatta.com>
Date: Thu, 28 Apr 2011 08:43:37 -0700
> On Thu, 28 Apr 2011 10:56:07 +0200
> Eric Dumazet <eric.dumazet@gmail.com> wrote:
>
>> Four years ago, Patrick made a change to hold rtnl mutex during netlink
>> dump callbacks.
>>
>> I believe it was a wrong move. This slows down concurrent dumps, making
>> good old /proc/net/ files faster than rtnetlink in some situations.
>>
>> This occurred to me because one "ip link show dev ..." was _very_ slow
>> on a workload adding/removing network devices in background.
>>
>> All dump callbacks are able to use RCU locking now, so this patch does
>> roughly a revert of commits :
>>
>> 1c2d670f366 : [RTNETLINK]: Hold rtnl_mutex during netlink dump callbacks
>> 6313c1e0992 : [RTNETLINK]: Remove unnecessary locking in dump callbacks
>>
>> This let writers fight for rtnl mutex and readers going full speed.
>>
>> It also takes care of phonet : phonet_route_get() is now called from rcu
>> read section. I renamed it to phonet_route_get_rcu()
>>
>> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
>> Cc: Patrick McHardy <kaber@trash.net>
>> Cc: Remi Denis-Courmont <remi.denis-courmont@nokia.com>
>
> Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Applied, thanks everyone!
next prev parent reply other threads:[~2011-05-02 22:28 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-28 8:56 [PATCH net-next-2.6] net: dont hold rtnl mutex during netlink dump callbacks Eric Dumazet
2011-04-28 15:40 ` Stephen Hemminger
2011-04-28 15:43 ` Stephen Hemminger
2011-04-28 15:53 ` Eric Dumazet
2011-05-02 22:27 ` David Miller [this message]
2011-05-17 22:18 ` [PATCH net-next-2.6] net: add rcu protection to netdev->ifalias Eric Dumazet
2011-05-17 22:25 ` Stephen Hemminger
2011-05-17 22:39 ` Eric Dumazet
2011-05-18 4:35 ` Eric Dumazet
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