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Subject: Re: [PATCH v1 01/25] net: core: device_rename: Use rwsem instead of a
 seqcount
To:     David Miller <davem@davemloft.net>, tglx@linutronix.de
Cc:     stephen@networkplumber.org, a.darwish@linutronix.de,
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From:   Eric Dumazet <eric.dumazet@gmail.com>
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Date:   Tue, 19 May 2020 20:18:19 -0700
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On 5/19/20 7:57 PM, David Miller wrote:
> From: Thomas Gleixner <tglx@linutronix.de>
> Date: Wed, 20 May 2020 01:42:30 +0200
> 
>> Stephen Hemminger <stephen@networkplumber.org> writes:
>>> On Wed, 20 May 2020 00:23:48 +0200
>>> Thomas Gleixner <tglx@linutronix.de> wrote:
>>>> No. We did not. -ENOTESTCASE
>>>
>>> Please try, it isn't that hard..
>>>
>>> # time for ((i=0;i<1000;i++)); do ip li add dev dummy$i type dummy; done
>>>
>>> real	0m17.002s
>>> user	0m1.064s
>>> sys	0m0.375s
>>
>> And that solves the incorrectness of the current code in which way?
> 
> You mentioned that there wasn't a test case, he gave you one to try.
> 

I do not think this would ever use device rename, nor netdev_get_name()

None of this stuff is fast path really.

# time for ((i=1;i<1000;i++)); do ip li add dev dummy$i type dummy; done

real	0m1.127s
user	0m0.270s
sys	0m1.039s