Re: question about softirqs

From: Andi Kleen <andi@firstfloor.org>
To: Chris Friesen <cfriesen@nortel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
	netdev@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
	Steven Rostedt <rostedt@goodmis.org>,
	linuxppc-dev@ozlabs.org, Andi Kleen <andi@firstfloor.org>,
	paulus@samba.org, Thomas Gleixner <tglx@linutronix.de>,
	David Miller <davem@davemloft.net>
Subject: Re: question about softirqs
Date: Wed, 13 May 2009 19:01:22 +0200	[thread overview]
Message-ID: <20090513170122.GZ19296@one.firstfloor.org> (raw)
In-Reply-To: <4A0AE19D.9040509@nortel.com>

On Wed, May 13, 2009 at 09:05:01AM -0600, Chris Friesen wrote:
> Andi Kleen wrote:
> > Thomas Gleixner <tglx@linutronix.de> writes:
> 
> >>Err, no. Chris is completely correct:
> >>
> >>        if (!in_interrupt())
> >>		wakeup_softirqd();
> > 
> > Yes you have to wake it up just in case, but it doesn't normally
> > process the data because a normal softirq comes in faster. It's
> > just a safety policy. 
> 
> What about the scenario I raised earlier, where we have incoming network
> packets,

network packets are normally processed by the network packet interrupt's
softirq or alternatively in the NAPI poll loop.

-Andi
-- 
ak@linux.intel.com -- Speaking for myself only.