[linux-pm] [RFC 1/3] support powermac G5 CPU hotplug

[Pavel Machek]

Hi!

> This patch allows "hotplugging" of CPUs on G5 machines. CPUs that are
> disabled are put into an idle loop with interrupts hard-disabled, to wake
> them up again we kick them just like when bringing them up.
> 
> Maybe there's some way to actually turn off those CPUs even more?
> 
> Cc: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> 


> --- linux-2.6-git.orig/arch/powerpc/kernel/smp.c	2006-12-11 23:34:47.693716759 +0100
> +++ linux-2.6-git/arch/powerpc/kernel/smp.c	2006-12-11 23:37:55.017716759 +0100
> @@ -558,6 +558,9 @@ int __devinit start_secondary(void *unus
>  
>  	local_irq_enable();
>  
> +	/* who knows what context the processor might have died in... */
> +	task_thread_info(paca[cpu].__current)->preempt_count = 0;
> +

?? Context for downing cpu should better be well-defined. Just do this
in cpu_die if it is really required.
							Pavel
-- 
Thanks for all the (sleeping) penguins.