Re: [PATCH V5 5/7] cpufreq: amd-pstate: Update amd-pstate preferred core ranking dynamically

On Tue, Sep 05, 2023 at 09:51:14AM +0800, Meng Li wrote:

+static void amd_pstate_update_highest_perf(unsigned int cpu) +{

• struct cpufreq_policy *policy;
• struct amd_cpudata *cpudata;
• u32 prev_high = 0, cur_high = 0;
• u64 highest_perf;
• int ret;
• if (!prefcore)

• return;
  

• ret = amd_pstate_get_highest_perf(cpu, &highest_perf);
• if (ret)

• return;
  

• policy = cpufreq_cpu_get(cpu);
• cpudata = policy->driver_data;
• cur_high = highest_perf;
• prev_high = READ_ONCE(cpudata->cppc_highest_perf);
• if (prev_high != cur_high) {

• WRITE_ONCE(cpudata->cppc_highest_perf, cur_high);
  

• sched_set_itmt_core_prio(cur_high, cpu);
  

I just noticed, your cur_high is explicitly 'u32', but sched_set_itmt_core_prio() and the rest of the scheduler use 'int' (aka s32). If you somehow get that top bit set things might not work out as expected.

Please double check.

• }
• cpufreq_cpu_put(policy);

+}