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Subject: Re: [patch] rt: res_counter fix, v2
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@tglx.de>,
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       Steven Rostedt <rostedt@goodmis.org>, Carsten Emde <ce@ceag.ch>,
       Clark Williams <williams@redhat.com>
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Date: Thu, 12 Feb 2009 15:58:04 +0100
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On Thu, 2009-02-12 at 15:50 +0100, Frederic Weisbecker wrote:
>  
> > maybe we should initialize it to -1 to make this more apparent?
> 
> 
> Or why not set p->{hard,soft}irq_disable_ip = NULL ? (or 0, I don't know its type).

It is to reflect the actual state at copy_process(), although I think
here's a little buglet:

ifdef CONFIG_TRACE_IRQFLAGS
	p->irq_events = 0;
#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
	p->hardirqs_enabled = 1;
#else
	p->hardirqs_enabled = 0;
#endif
	p->hardirq_enable_ip = 0;
	p->hardirq_enable_event = 0;
	p->hardirq_disable_ip = _THIS_IP_;
	p->hardirq_disable_event = 0;
	p->softirqs_enabled = 1;
	p->softirq_enable_ip = _THIS_IP_;
	p->softirq_enable_event = 0;
	p->softirq_disable_ip = 0;
	p->softirq_disable_event = 0;
	p->hardirq_context = 0;
	p->softirq_context = 0;
#endif

I think the hardirq_enable/disable_ip should also depend on
__ARCH_WANT_INTERRUPTS_ON_CTXSW.