Re: [patch 07/34] alpha: Use generic idle loop
From: Thomas Gleixner
Date: Fri Mar 29 2013 - 07:23:09 EST
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
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