From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: David Miller <davem@davemloft.net>
Cc: jkacur@gmail.com, linux-rt-users@vger.kernel.org,
linux-kernel@vger.kernel.org, mingo@elte.hu, tglx@linutronix.de,
rostedt@goodmis.org
Subject: Re: [PATCH] BUG: using smp_processor_id() in preemptible [00000000] code: caller is __qdisc_run
Date: Mon, 11 Aug 2008 23:09:38 +0200 [thread overview]
Message-ID: <1218488979.15798.39.camel@lappy.programming.kicks-ass.net> (raw)
In-Reply-To: <20080811.140014.94581847.davem@davemloft.net>
On Mon, 2008-08-11 at 14:00 -0700, David Miller wrote:
> From: "John Kacur" <jkacur@gmail.com>
> Date: Mon, 11 Aug 2008 15:11:46 +0200
>
> > __qdisc_run() calls qdisc_restart() which calls
> > handle_dev_cpu_collision(skb, dev, q); and then the problem shows up
> > here:
> > __get_cpu_var(netdev_rx_stat).cpu_collision++;
> >
> > The solution is to disable interrupts around the above increment. Here
> > is an attached patch to do so. (Thank's to Peter Zijlstra for help in
> > the analysis and dropping the answer in my lap, so if I got it right
> > it is due to his help, but if I messed it up, then I did that part all
> > by myself.)
>
> __qdisc_run() always runs in software interrupt context,
> so I guess this is some problem with the -rt stuff running
> software interrupts in threads?
Hmm, good point - and those threads should be cpu affine on -rt if I'm
not mistaken. Steven, do you happen to remember details?
next prev parent reply other threads:[~2008-08-11 21:18 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-11 13:11 John Kacur
2008-08-11 21:00 ` David Miller
2008-08-11 21:09 ` Peter Zijlstra [this message]
2008-08-11 21:23 ` David Miller
2008-08-12 1:22 ` Steven Rostedt
2008-08-12 2:06 ` Gregory Haskins
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