[RFC] sysfs cpu cleanup

[Nathan Lynch]

On Thu, 2004-11-18 at 20:30, David Gibson wrote:
> Index: working-2.6/arch/ppc64/kernel/smp.c
> ===================================================================
> --- working-2.6.orig/arch/ppc64/kernel/smp.c	2004-10-19 13:37:56.000000000 +1000
> +++ working-2.6/arch/ppc64/kernel/smp.c	2004-11-17 17:56:42.000000000 +1100
> @@ -82,6 +82,8 @@
>  void smp_call_function_interrupt(void);
>  extern long register_vpa(unsigned long flags, unsigned long proc,
>  			 unsigned long vpa);
> +extern void register_cpu_online(int cpu);
> +extern void unregister_cpu_online(int cpu);
>  
>  int smt_enabled_at_boot = 1;
>  
> @@ -291,6 +293,8 @@
>  	int cpu_status;
>  	unsigned int pcpu = get_hard_smp_processor_id(cpu);
>  
> +	unregister_cpu_online(cpu);
> +
>  	for (tries = 0; tries < 25; tries++) {
>  		cpu_status = query_cpu_stopped(pcpu);
>  		if (cpu_status == 0 || cpu_status == -1)
> @@ -919,6 +923,11 @@
>  	while (!cpu_online(cpu))
>  		cpu_relax();
>  
> +#ifdef CONFIG_HOTPLUG_CPU
> +	if (system_state >= SYSTEM_RUNNING) /* This is a hotplug */
> +		register_cpu_online(cpu);
> +#endif /* CONFIG_HOTPLUG_CPU */
> +
>  	return 0;
>  }

I apologize for not noticing this before :/

Instead of explicitly calling into the sysfs.c code from smp.c, I think
it would be better to use a cpu hotplug notifier block.  Even without
CONFIG_HOTPLUG_CPU turned on, you get the "online" notification at boot
for each cpu as it is brought up.  See the ppc64 numa code for an
example usage.


Nathan