Re: [PATCH 1/1] PM: Add arch_suspend_disable_nonboot_cpus

[Brian King <brking@linux.vnet.ibm.com>]

On 02/23/2010 09:43 AM, Pavel Machek wrote:
> Hi!
> 
>>> OK
>>>
>>>> Here is an alternative implementation of the patch. My test machine is
>>>> currently unavailable, so it is not yet been tested. How does this one look?
>>>
>>> Well, I'd like to do that cleanly from the start.
>>>
>>> Now, the problem is that PM_SLEEP_SMP selects HOTPLUG_CPU, because
>>> that's necessary for the other architectures to make SMP suspend work, but it's
>>> not necessary on your architecture.  Moreover, you don't need to compile
>>> enable_nonboot_cpus() at all.
> 
>>  At least for the architecture I am enabling this support for
>> (PPC_PSERIES), upon looking closer, it looks like PM_SLEEP_SMP was
>> never defined, so enable_nonboot_cpus and disable_nonboot_cpus were
>> always nooped before, which I didn't previously realize. We probably
>> want to retain this behavior.  >
> 
> (Please wrap at column 80)
> 
> This patch is already way better than the original one, but... Why do
> you want enable/disable_nonboot_cpus to be noped out?
> 									Pavel

Today for PPC_PSERIES, PM_SLEEP_SMP is never defined, so for all the
current code paths that call enable/disable_nonboot_cpus (power off,
kexec), these functions are noops. I don't want to change that behavior.
I figured I can just use the prepare_late and wake pm functions to do
the work I need to do. Let me know if you think this is a reasonable
approach and I'll be happy to resend the patch with an appropriate
subject line and description.

Thanks,

Brian

-- 
Brian King
Linux on Power Virtualization
IBM Linux Technology Center