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Date: Fri, 29 Mar 2013 12:22:54 +0100 (CET)
From: Thomas Gleixner <tglx@linutronix.de>
To: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
cc: LKML <linux-kernel@vger.kernel.org>, linux-arch@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
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        Richard Henderson <rth@twiddle.net>,
        Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
        Matt Turner <mattst88@gmail.com>
Subject: Re: [patch 07/34] alpha: Use generic idle loop
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On Thu, 28 Mar 2013, Srivatsa S. Bhat wrote:
> (In all my replies, I'm referring to the code in your v2 on your git
> tree, but replying to the corresponding patches in your v1).
> 
> So, in alpha, we poll in cpu idle. In the generic implementation in
> kernel/cpu/idle.c, arch_cpu_idle() is defined as:
> 
> void __weak arch_cpu_idle(void)
> {
>         cpu_idle_poll();
> }
> 
> Should it not have been:
> 
> void __weak arch_cpu_idle(void)
> {
> 	current_set_polling();
>         cpu_idle_poll();
> 	current_clr_polling();
> }
> 
> instead?

Hmm, we should not clear it at all, because we are always polling and
never leave polling mode. So instead of calling cpu_idle_poll from the
weak arch_cpu_idle() we should set cpu_idle_force_poll so we drop into

	if (cpu_idle_force_poll) {
		cpu_idle_poll();
	} else ...

which keeps the polling flag set.

Thanks,

	tglx