Subject: Re: [PATCH] powerpc/sysfs: disable hotplug for the boot cpu

From: Benjamin Herrenschmidt <[email-masked]>
Date: Sat, 01 Jun 2013 07:49:44 +1000

On Tue, 2013-05-28 at 15:59 +0800, Zhao Chenhui wrote:
> Some features depend on the boot cpu, for instance, hibernate/suspend.
> So disable hotplug for the boot cpu.

Don't we have code to "move" the boot CPU around when that happens ?

Ben.

> Signed-off-by: Zhao Chenhui <[email-masked]>
> ---
>  arch/powerpc/kernel/sysfs.c |    4 +++-
>  1 files changed, 3 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
> index e68a845..294b1c4e 100644
> --- a/arch/powerpc/kernel/sysfs.c
> +++ b/arch/powerpc/kernel/sysfs.c
> @@ -655,8 +655,10 @@ static int __init topology_init(void)
>  		 * CPU.  For instance, the boot cpu might never be valid
>  		 * for hotplugging.
>  		 */
> -		if (ppc_md.cpu_die)
> +		if (ppc_md.cpu_die && cpu != boot_cpuid)
>  			c->hotpluggable = 1;
> +		else
> +			c->hotpluggable = 0;
>  
>  		if (cpu_online(cpu) || c->hotpluggable) {
>  			register_cpu(c, cpu);