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From: Stephen Hemminger <shemminger@vyatta.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Linux Netdev List <netdev@vger.kernel.org>
Subject: Re: PATCH net-next-2.6] linkwatch: linkwatch_forget_dev() to speedup device dismantle
Date: Mon, 16 Nov 2009 14:39:17 -0800	[thread overview]
Message-ID: <20091116143917.14e4fa4f@s6510> (raw)
In-Reply-To: <4B01C938.8000705@gmail.com>

On Mon, 16 Nov 2009 22:50:48 +0100
Eric Dumazet <eric.dumazet@gmail.com> wrote:

> vlan_dev_stop() ->
> 	netif_carrier_off(dev) ->
> 		linkwatch_fire_event(dev) ->
> 			dev_hold() ...
> 
> And __linkwatch_run_queue() runs up to one second later...
> 
> A generic fix to this problem is to add a linkwatch_forget_dev() method
> to unlink the device from the list of watched devices.
> 
> dev->link_watch_next becomes dev->link_watch_list (and use a bit more memory),
> to be able to unlink device in O(1).
> 
> After patch :
> time ip link del eth3.103 ; time ip link del eth3.104 ; time ip link del eth3.105
> 
> real    0m0.024s
> user    0m0.000s
> sys     0m0.000s
> 
> real    0m0.032s
> user    0m0.000s
> sys     0m0.001s
> 
> real    0m0.033s
> user    0m0.000s
> sys     0m0.000s
> 
> 
> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>

Acked-by: Stephen Hemminger <shemminger@vyatta.com>

  reply	other threads:[~2009-11-16 22:39 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-11-16 18:01 [RFC] dev->refcnt long term holder Eric Dumazet
2009-11-16 19:02 ` Stephen Hemminger
2009-11-16 19:54   ` Eric Dumazet
2009-11-17  8:30     ` David Miller
2009-11-17  8:37       ` Herbert Xu
2009-11-17 17:58       ` Stephen Hemminger
2009-11-17 19:18         ` David Miller
2009-11-16 21:50 ` PATCH net-next-2.6] linkwatch: linkwatch_forget_dev() to speedup device dismantle Eric Dumazet
2009-11-16 22:39   ` Stephen Hemminger [this message]
2009-11-17 12:26     ` David Miller
2009-11-17 12:31       ` Herbert Xu
2009-11-17 15:59         ` Eric Dumazet
2009-11-18 13:05           ` David Miller

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