Date: Wed, 23 Jul 2008 13:16:07 -0700 (PDT)
Message-Id: <20080723.131607.79681752.davem@davemloft.net> (sfid-20080723_221612_258009_860821BE)
To: jarkao2@gmail.com
Cc: peterz@infradead.org, Larry.Finger@lwfinger.net, kaber@trash.net,
	torvalds@linux-foundation.org, akpm@linux-foundation.org,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-wireless@vger.kernel.org, mingo@redhat.com
Subject: Re: Kernel WARNING: at net/core/dev.c:1330
 __netif_schedule+0x2c/0x98()
From: David Miller <davem@davemloft.net>
In-Reply-To: <20080723114914.GF4561@ff.dom.local>
References: <1216810696.7257.175.camel@twins>
	<20080723113519.GE4561@ff.dom.local>
	<20080723114914.GF4561@ff.dom.local>
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From: Jarek Poplawski <jarkao2@gmail.com>
Date: Wed, 23 Jul 2008 11:49:14 +0000

> On Wed, Jul 23, 2008 at 11:35:19AM +0000, Jarek Poplawski wrote:
> > On Wed, Jul 23, 2008 at 12:58:16PM +0200, Peter Zijlstra wrote:
> ...
> > > When I look at the mac802.11 code in ieee80211_tx_pending() it looks
> > > like it can do with just one lock at a time, instead of all - but I
> > > might be missing some obvious details.
> > > 
> > > So I guess my question is, is netif_tx_lock() here to stay, or is the
> > > right fix to convert all those drivers to use __netif_tx_lock() which
> > > locks only a single queue?
> > > 
> > 
> > It's a new thing mainly for new hardware/drivers, and just after
> > conversion (older drivers effectively use __netif_tx_lock()), so it'll
> > probably stay for some time until something better is found. David,
> > will tell the rest, I hope.
> 
> ...And, of course, these new drivers should also lock a single queue
> where possible.

It isn't going away.

There will always be a need for a "stop all the TX queues" operation.