Date: Sat, 18 Mar 2017 18:21:21 -0700 (PDT)
Message-Id: <20170318.182121.439615057765380575.davem@davemloft.net>
To: herbert@gondor.apana.org.au
Cc: eric.dumazet@gmail.com, elena.reshetova@intel.com,
        keescook@chromium.org, peterz@infradead.org, netdev@vger.kernel.org,
        bridge@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
        kuznet@ms2.inr.ac.ru, jmorris@namei.org, kaber@trash.net,
        stephen@networkplumber.org, ishkamiel@gmail.com, dwindsor@gmail.com,
        akpm@linux-foundation.org
Subject: Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to
 refcount_t
From: David Miller <davem@davemloft.net>
In-Reply-To: <20170318164759.GA23837@gondor.apana.org.au>
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        <20170318164759.GA23837@gondor.apana.org.au>
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From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Sun, 19 Mar 2017 00:47:59 +0800

> Eric Dumazet <eric.dumazet@gmail.com> wrote:
>> On Fri, 2017-03-17 at 07:42 +0000, Reshetova, Elena wrote:
>> 
>>> Should we then first measure the actual numbers to understand what we
>>> are talking here about? 
>>> I would be glad to do it if you suggest what is the correct way to do
>>> measurements here to actually reflect the real life use cases. 
>> 
>> How have these patches been tested in real life exactly ?
>> 
>> Can you quantify number of added cycles per TCP packet, where I expect
>> we have maybe 20 atomic operations in all layers ...
> 
> I completely agree.  I think this thing needs to default to the
> existing atomic_t behaviour.

I totally agree as well, the refcount_t facility as-is is unacceptable
for networking.