ACPI: Update the t-state for every affected cpu when t-state is changed

According to ACPI spec, the _TSD object provides T-state control cross
logical processor dependency information to OSPM. So the t-state
coordination should be considered when T-state for one cpu is changed.

According to ACPI spec, three types of coordination are defined.
SW_ALL, SW_ANY and HW_ALL.

SW_ALL: it means that OSPM needs to initiate T-state transition on
all processors in the domain. It is necessary to call throttling set function
for all affected cpus.

SW_ANY: it means that OSPM may initiate T-state transition on any processor in
the domain.

HW_ALL: Spec only says that hardware will perform the coordination and doesn't
recommend how OSPM coordinate T-state among the affected cpus. So it is treated
as the type of SW_ALL. It means that OSPM needs to initiate t-state transition
on all the processors in the domain.

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 74 insertions, 5 deletions

diff --git a/drivers/acpi/processor_throttling.c b/drivers/acpi/processor_throttling.c
index 18a873a55256..86c790e9f4fc 100644
--- a/drivers/acpi/processor_throttling.c
+++ b/drivers/acpi/processor_throttling.c
@@ -68,7 +68,7 @@ static int acpi_processor_update_tsd_coord(void)
 
         /*
          * Now that we have _TSD data from all CPUs, lets setup T-state
-         * coordination among all CPUs.
+         * coordination between all CPUs.
          */
         for_each_possible_cpu(i) {
                 pr = processors[i];
@@ -988,6 +988,11 @@ int acpi_processor_set_throttling(struct acpi_processor *pr, int state)
 {
         cpumask_t saved_mask;
         int ret;
+        unsigned int i;
+        struct acpi_processor *match_pr;
+        struct acpi_processor_throttling *p_throttling;
+        struct throttling_tstate t_state;
+        cpumask_t online_throttling_cpus;
 
         if (!pr)
                 return -EINVAL;
@@ -998,12 +1003,76 @@ int acpi_processor_set_throttling(struct acpi_processor *pr, int state)
         if ((state < 0) || (state > (pr->throttling.state_count - 1)))
                 return -EINVAL;
 
+        saved_mask = current->cpus_allowed;
+        t_state.target_state = state;
+        p_throttling = &(pr->throttling);
+        cpus_and(online_throttling_cpus, cpu_online_map,
+                        p_throttling->shared_cpu_map);
         /*
-         * Migrate task to the cpu pointed by pr.
+         * The throttling notifier will be called for every
+         * affected cpu in order to get one proper T-state.
+         * The notifier event is THROTTLING_PRECHANGE.
          */
-        saved_mask = current->cpus_allowed;
-        set_cpus_allowed(current, cpumask_of_cpu(pr->id));
-        ret = pr->throttling.acpi_processor_set_throttling(pr, state);
+        for_each_cpu_mask(i, online_throttling_cpus) {
+                t_state.cpu = i;
+                acpi_processor_throttling_notifier(THROTTLING_PRECHANGE,
+                                                        &t_state);
+        }
+        /*
+         * The function of acpi_processor_set_throttling will be called
+         * to switch T-state. If the coordination type is SW_ALL or HW_ALL,
+         * it is necessary to call it for every affected cpu. Otherwise
+         * it can be called only for the cpu pointed by pr.
+         */
+        if (p_throttling->shared_type == DOMAIN_COORD_TYPE_SW_ANY) {
+                set_cpus_allowed(current, cpumask_of_cpu(pr->id));
+                ret = p_throttling->acpi_processor_set_throttling(pr,
+                                                t_state.target_state);
+        } else {
+                /*
+                 * When the T-state coordination is SW_ALL or HW_ALL,
+                 * it is necessary to set T-state for every affected
+                 * cpus.
+                 */
+                for_each_cpu_mask(i, online_throttling_cpus) {
+                        match_pr = processors[i];
+                        /*
+                         * If the pointer is invalid, we will report the
+                         * error message and continue.
+                         */
+                        if (!match_pr) {
+                                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+                                        "Invalid Pointer for CPU %d\n", i));
+                                continue;
+                        }
+                        /*
+                         * If the throttling control is unsupported on CPU i,
+                         * we will report the error message and continue.
+                         */
+                        if (!match_pr->flags.throttling) {
+                                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+                                        "Throttling Controll is unsupported "
+                                        "on CPU %d\n", i));
+                                continue;
+                        }
+                        t_state.cpu = i;
+                        set_cpus_allowed(current, cpumask_of_cpu(i));
+                        ret = match_pr->throttling.
+                                acpi_processor_set_throttling(
+                                match_pr, t_state.target_state);
+                }
+        }
+        /*
+         * After the set_throttling is called, the
+         * throttling notifier is called for every
+         * affected cpu to update the T-states.
+         * The notifier event is THROTTLING_POSTCHANGE
+         */
+        for_each_cpu_mask(i, online_throttling_cpus) {
+                t_state.cpu = i;
+                acpi_processor_throttling_notifier(THROTTLING_POSTCHANGE,
+                                                        &t_state);
+        }
         /* restore the previous state */
         set_cpus_allowed(current, saved_mask);
         return ret;