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From: John Baldwin <jhb@freebsd.org>
To: Jack Vogel <jfvogel@gmail.com>
Date: Wed, 26 Sep 2012 09:55:14 -0400
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	(bigwig.baldwin.cx); Wed, 26 Sep 2012 10:14:35 -0400 (EDT)
Cc: freebsd-net@freebsd.org, Vijay Singh <vijju.singh@gmail.com>
Subject: Re: ixgbe rx & tx locks
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On Tuesday, September 25, 2012 4:40:58 pm Jack Vogel wrote:
> Ah yes, at one time I was keeping the RX side lock when calling the stack,
> but then as I recall that had problems, so the code now releases and
> reaquires
> as you can see. It results in some contention but I'm not sure that's
> avoidable.
> 
> I've seen some LRO related panics on the 1G driver that may be related to
> this lock release, or that's one theory I have..
> 
> Thanks for the testing Vijay!

You only have to drop the RX lock around if_input() if you use the same lock
for both TX and RX (as if_transmit() / if_start() can be invoked while locks
in the network stack are held).  If WITNESS complains, the fix is to only use
the MTX_NETWORK_LOCK "lock type name" for your transmit ring locks, not for
RX.

-- 
John Baldwin