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SubjectRe: [PATCH] cpufreq: cppc_cpufreq: Initialize shared cpu's perf capabilities
On 28-03-18, 17:31, Shunyong Yang wrote:
> When multiple cpus are related in one cpufreq policy, the first online
> cpu will be chosen by default to handle cpufreq operations. Let's take
> cpu0 and cpu1 as an example.
>
> When cpu0 is offline, policy->cpu will be shifted to cpu1. Cpu1's should
> be initialized. Otherwise, perf capabilities are 0s and speed change can
> not take effect.
>
> This patch copies perf capabilities of the first online cpu to other
> shared cpus when policy shared type is CPUFREQ_SHARED_TYPE_ANY.
>
> Cc: Joey Zheng <yu.zheng@hxt-semitech.com>
> Signed-off-by: Shunyong Yang <shunyong.yang@hxt-semitech.com>
> ---
>
> The original RFC link,
> https://patchwork.kernel.org/patch/10299055/.
>
> This patch solves same issue as RFC above.
>
> Patch name is changed as code is too much different with RFC above.
>
> Remove extra init() per Viresh Kumar's comments and only handle
> CPPC CPUFREQ_SHARED_TYPE_ANY case.
>
> ---
> drivers/cpufreq/cppc_cpufreq.c | 12 +++++++++++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
> index 8f7b21a4d537..dc625a93a58e 100644
> --- a/drivers/cpufreq/cppc_cpufreq.c
> +++ b/drivers/cpufreq/cppc_cpufreq.c
> @@ -164,8 +164,18 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
> policy->cpuinfo.transition_latency = cppc_get_transition_latency(cpu_num);
> policy->shared_type = cpu->shared_type;
>
> - if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
> + if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) {
> + int i;
> +
> cpumask_copy(policy->cpus, cpu->shared_cpu_map);
> +
> + for_each_cpu(i, policy->cpus) {
> + if (i != policy->cpu)

I would rather do:

if (unlikely(i == policy->cpu))
continue;

> + memcpy(&all_cpu_data[i]->perf_caps,
> + &cpu->perf_caps,
> + sizeof(cpu->perf_caps));
> + }
> + }
> else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) {

It should be:

} else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) {

> /* Support only SW_ANY for now. */
> pr_debug("Unsupported CPU co-ord type\n");

And thanks for making it work this way.

--
viresh

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