Re: [PATCH 3/3] ACPI: cpufreq: Add ITMT support when CPPC enabled for Zhaoxin CPUs

[Linda Chai(BJ-RD)]

Hi ,Ricardo
About this itmt dumplicated code in intel-pstate and acpi-cpufreq driver;
how about we put these common codes in arch/x86/kernel/itmt.c?
in intel-pstate/acpi-cpufreq driver, it only get highest frequency through cppc interface and call sched_set_itmt_core_prio provided by itmt.c;
    in the sched_set_itmt_core_prio, do these following works:
1) set core priorty according to the highest frequency;
2) check whether cores’highest frequencies are different, if yes, set itmt capable & enable;
3) check whether all online cores have updated core priority, which guarantee rebuild_sched_domains will get the correct priority info for each online core;

Following this rule, the patch looks like this:
diff --git a/arch/x86/kernel/itmt.c b/arch/x86/kernel/itmt.c
index 9a7c03d47861..eb24df2826bc 100644
--- a/arch/x86/kernel/itmt.c
+++ b/arch/x86/kernel/itmt.c
@@ -22,6 +22,7 @@
#include <linux/mutex.h>
#include <linux/sysctl.h>
#include <linux/nodemask.h>
+#include <linux/itmt.h>

 static DEFINE_MUTEX(itmt_update_mutex);
DEFINE_PER_CPU_READ_MOSTLY(int, sched_core_priority);
@@ -162,6 +163,13 @@ int arch_asym_cpu_priority(int cpu)
     return per_cpu(sched_core_priority, cpu);
}

+/* The work item is needed to avoid CPU hotplug locking issues */
+static void sched_itmt_work_fn(struct work_struct *work)
+{
+     sched_set_itmt_support();
+}
+static DECLARE_WORK(sched_itmt_work, sched_itmt_work_fn);
+
/**
  * sched_set_itmt_core_prio() - Set CPU priority based on ITMT
  * @prio:     Priority of @cpu
@@ -176,7 +184,36 @@ int arch_asym_cpu_priority(int cpu)
  * the CPU priorities. The sched domains have no
  * dependency on CPU priorities.
  */
+
+static u64 max_highest_prio = 0, min_highest_prio = U64_MAX;
+static bool core_priority_diff=false;
+static struct cpumask core_prio_cpumask;
void sched_set_itmt_core_prio(int prio, int cpu)
{
     per_cpu(sched_core_priority, cpu) = prio;
+     cpumask_set_cpu(cpu, &core_prio_cpumask);
+
+     if (max_highest_prio <= min_highest_prio)
+     {
+            if (prio > max_highest_prio)
+                   max_highest_prio = prio;
+
+            if (prio < min_highest_prio)
+                   min_highest_prio = prio;
+
+            if (max_highest_prio > min_highest_prio)
+                   core_priority_diff = true;
+     }
+
+     if (core_priority_diff && cpumask_equal(&core_prio_cpumask, cpu_online_mask))
+     {
+            /*
+            * This code  can be run during CPU online under the CPU hotplug locks,
+            * so sched_set_itmt cannot be called from here.
+            * queue a work item to invoke it
+            */
+            pr_debug("queue a work to set itmt support and enable\n");
+            schedule_work(&sched_itmt_work);
+     }
+
}
diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index 37f1cdf46d29..3e5e0f66b2ed 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -30,6 +30,7 @@
#include <acpi/processor.h>
#include <acpi/cppc_acpi.h>

+#include <linux/itmt.h>
#include <asm/msr.h>
#include <asm/processor.h>
#include <asm/cpufeature.h>
@@ -663,8 +664,17 @@ static u64 get_max_boost_ratio(unsigned int cpu)

      return div_u64(highest_perf << SCHED_CAPACITY_SHIFT, nominal_perf);
}
+
+static void core_set_itmt_prio(int cpu)
+{
+     u64 highest_perf;
+     cppc_get_highest_perf(cpu, &highest_perf);
+     sched_set_itmt_core_prio(highest_perf, cpu);
+}
+
#else
static inline u64 get_max_boost_ratio(unsigned int cpu) { return 0; }
+static void core_set_itmt_prio(int cpu) {}
#endif

 static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
@@ -677,7 +687,7 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
     unsigned int valid_states = 0;
     unsigned int result = 0;
     u64 max_boost_ratio;
-     unsigned int i;
+     unsigned int i,j;
#ifdef CONFIG_SMP
     static int blacklisted;
#endif
@@ -741,6 +751,10 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
            pr_info_once("overriding BIOS provided _PSD data\n");
     }
#endif
+     for_each_cpu(j,policy->cpus)
+     {
+            core_set_itmt_prio(j);
+     }

      /* capability check */
     if (perf->state_count <= 1) {
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index dbbf299f4219..4b04e6db9d5b 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -27,6 +27,7 @@
#include <linux/pm_qos.h>
#include <linux/bitfield.h>
#include <trace/events/power.h>
+#include <linux/itmt.h>

 #include <asm/cpu.h>
#include <asm/div64.h>
@@ -340,23 +341,14 @@ static bool intel_pstate_get_ppc_enable_status(void)

 #ifdef CONFIG_ACPI_CPPC_LIB

-/* The work item is needed to avoid CPU hotplug locking issues */
-static void intel_pstste_sched_itmt_work_fn(struct work_struct *work)
-{
-     sched_set_itmt_support();
-}
-
-static DECLARE_WORK(sched_itmt_work, intel_pstste_sched_itmt_work_fn);
-
#define CPPC_MAX_PERF  U8_MAX

 static void intel_pstate_set_itmt_prio(int cpu)
{
-     struct cppc_perf_caps cppc_perf;
-     static u32 max_highest_perf = 0, min_highest_perf = U32_MAX;
+     u64 highest_perf;
     int ret;

-     ret = cppc_get_perf_caps(cpu, &cppc_perf);
+     ret = cppc_get_highest_perf(cpu,&highest_perf);
     if (ret)
            return;

@@ -365,33 +357,15 @@ static void intel_pstate_set_itmt_prio(int cpu)
      * In this case we can't use CPPC.highest_perf to enable ITMT.
      * In this case we can look at MSR_HWP_CAPABILITIES bits [8:0] to decide.
      */
-     if (cppc_perf.highest_perf == CPPC_MAX_PERF)
-            cppc_perf.highest_perf = HWP_HIGHEST_PERF(READ_ONCE(all_cpu_data[cpu]->hwp_cap_cached));
+     if (highest_perf == CPPC_MAX_PERF)
+            highest_perf = HWP_HIGHEST_PERF(READ_ONCE(all_cpu_data[cpu]->hwp_cap_cached));

      /*
      * The priorities can be set regardless of whether or not
      * sched_set_itmt_support(true) has been called and it is valid to
      * update them at any time after it has been called.
      */
-     sched_set_itmt_core_prio(cppc_perf.highest_perf, cpu);
-
-     if (max_highest_perf <= min_highest_perf) {
-            if (cppc_perf.highest_perf > max_highest_perf)
-                   max_highest_perf = cppc_perf.highest_perf;
-
-            if (cppc_perf.highest_perf < min_highest_perf)
-                   min_highest_perf = cppc_perf.highest_perf;
-
-            if (max_highest_perf > min_highest_perf) {
-                   /*
-                   * This code can be run during CPU online under the
-                   * CPU hotplug locks, so sched_set_itmt_support()
-                   * cannot be called from here.  Queue up a work item
-                   * to invoke it.
-                   */
-                   schedule_work(&sched_itmt_work);
-            }
-     }
+     sched_set_itmt_core_prio(highest_perf, cpu);
}

 static int intel_pstate_get_cppc_guaranteed(int cpu)
Thanks
Linda



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