netdev - Re: Scalability of interface creation and deletion

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Message-ID: <4DC57702.4090606@candelatech.com>
Date:	Sat, 07 May 2011 09:44:50 -0700
From:	Ben Greear <greearb@...delatech.com>
To:	Eric Dumazet <eric.dumazet@...il.com>
CC:	Alex Bligh <alex@...x.org.uk>, netdev@...r.kernel.org
Subject: Re: Scalability of interface creation and deletion

On 05/07/2011 09:37 AM, Eric Dumazet wrote:
> Le samedi 07 mai 2011 à 09:23 -0700, Ben Greear a écrit :
>
>> I wonder if it would be worth having a 'delete me soon'
>> method to delete interfaces that would not block on the
>> RCU code.
>>
>> The controlling programs could use netlink messages to
>> know exactly when an interface was truly gone.
>>
>> That should allow some batching in the sync-net logic
>> too, if user-space code deletes 1000 interfaces very
>> quickly, for instance...
>>
>
> I suggested in the past to have an extension of batch capabilities, so
> that one kthread could have 3 separate lists of devices being destroyed
> in //,
>
> This daemon would basically loop on one call to synchronize_rcu(), and
> transfert list3 to deletion, list2 to list3, list1 to list2, loop,
> eventually releasing RTNL while blocked in synchronize_rcu()
>
> This would need to allow as you suggest an asynchronous deletion method,
> or use a callback to wake the process blocked on device delete.

I'd want to at least have the option to not block the calling
process...otherwise, it would be a lot more difficult to
quickly delete 1000 interfaces.  You'd need 1000 threads, or
sockets, or something to parallelize it otherwise, eh?

Thanks,
Ben

-- 
Ben Greear <greearb@...delatech.com>
Candela Technologies Inc  http://www.candelatech.com
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