intel_pstate: Set core to min P state during core offline

Change to use the new ->stop_cpu() callback to do clean up during CPU
hotplug. The requested P state for an offline core will be used by the
hardware coordination function to select the package P state. If the
core is under load when it is offlined it will fix the package P state
floor to the requested P state of offline core.

Reported-by: Patrick Marlier <patrick.marlier@gmail.com>
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 11 insertions, 8 deletions

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 9ab109c0f90c..bcb9a6d0ae11 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -446,7 +446,7 @@ static void core_set_pstate(struct cpudata *cpudata, int pstate)
         if (limits.no_turbo)
                 val |= (u64)1 << 32;
 
-        wrmsrl(MSR_IA32_PERF_CTL, val);
+        wrmsrl_on_cpu(cpudata->cpu, MSR_IA32_PERF_CTL, val);
 }
 
 static struct cpu_defaults core_params = {
@@ -771,14 +771,17 @@ static int intel_pstate_verify_policy(struct cpufreq_policy *policy)
         return 0;
 }
 
-static int intel_pstate_cpu_exit(struct cpufreq_policy *policy)
+static void intel_pstate_stop_cpu(struct cpufreq_policy *policy)
 {
-        int cpu = policy->cpu;
+        int cpu_num = policy->cpu;
+        struct cpudata *cpu = all_cpu_data[cpu_num];
 
-        del_timer(&all_cpu_data[cpu]->timer);
-        kfree(all_cpu_data[cpu]);
-        all_cpu_data[cpu] = NULL;
-        return 0;
+        pr_info("intel_pstate CPU %d exiting\n", cpu_num);
+
+        del_timer(&all_cpu_data[cpu_num]->timer);
+        intel_pstate_set_pstate(cpu, cpu->pstate.min_pstate);
+        kfree(all_cpu_data[cpu_num]);
+        all_cpu_data[cpu_num] = NULL;
 }
 
 static int intel_pstate_cpu_init(struct cpufreq_policy *policy)
@@ -816,7 +819,7 @@ static struct cpufreq_driver intel_pstate_driver = {
         .setpolicy      = intel_pstate_set_policy,
         .get            = intel_pstate_get,
         .init           = intel_pstate_cpu_init,
-        .exit           = intel_pstate_cpu_exit,
+        .stop_cpu       = intel_pstate_stop_cpu,
         .name           = "intel_pstate",
 };