netdev - Re: [PATCH v3 net] net: solve a NAPI race

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Date:   Mon, 27 Feb 2017 17:48:54 -0500 (EST)
From:   David Miller <davem@...emloft.net>
To:     stephen@...workplumber.org
Cc:     eric.dumazet@...il.com, netdev@...r.kernel.org
Subject: Re: [PATCH v3 net] net: solve a NAPI race

From: Stephen Hemminger <stephen@...workplumber.org>
Date: Mon, 27 Feb 2017 14:44:55 -0800

> On Mon, 27 Feb 2017 14:35:17 -0800
> Eric Dumazet <eric.dumazet@...il.com> wrote:
> 
>> On Mon, 2017-02-27 at 14:14 -0800, Stephen Hemminger wrote:
>> 
>> > The original design (as Davem mentioned) was that IRQ's must be disabled
>> > during device polling. If that was true, then the race above
>> > would be impossible.  
>> 
>> I would love to see an alternative patch.
> 
> Turn off busy poll? 
> The poll stuff runs risk of breaking more things.

Eric is exactly trying to make busy poll even more prominent in
the stack, not less prominent.

It's an important component of some performance improvements he is
working on.