Re: [PATCH] cpufreq: Set cpufreq_cpu_data to NULL before putting kobject

ethan zhao
2015-02-02T01:54:40Z

Viresh,

On 2015/1/30 12:14, Viresh Kumar wrote:
> On 30 January 2015 at 09:16, ethan zhao <ethan.zhao@oracle.com> wrote:
>> You mean the policy is shared by all CPUs, so PPC notification about one
> A policy may or maynot be shared by multiple CPUs. It all depends on your
> systems configuration. All CPUs which share clock line, share a policy.
>
> You can verify that from /sys/devices/system/cpu/cpu*/related_cpus. This
> gives the CPUs that share policy.
>
>> CPU should update all CPU's policy, right ? even the requested CPU is
>> shutting down.
> CPUs sharing policy have a single policy structure. And so policy would
> be updated for all CPUs that share the poilcy. Even if some cpu goes down,
> the policy might still be up and running.
Let' me check ACPI spec and BIOS to match your implementation.

About that patch you suggested, there is another question left pending:

Policy will be freed only when that's last CPU shutting down, how does it
happen when system booting ?

The description of the patch would be wrong (the Xen_bus call stack) --
Did the xen_bus shut down every CPU till the last during booting ?

Thanks,
Ethan
>
> --
> viresh