perf/x86/intel/rapl: Convert to hotplug state machine

Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.

Signed-off-by: Richard Cochran <rcochran@linutronix.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160713153334.008808086@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/events/intel/rapl.c b/arch/x86/events/intel/rapl.c
index e30eef4f29a6f6034e46beab4a559f9994311c34..6255ede56174e53ce4889426c2a879598e3a74d8 100644 (file)
--- a/arch/x86/events/intel/rapl.c
+++ b/arch/x86/events/intel/rapl.c
@@ -555,14 +555,14 @@ const struct attribute_group *rapl_attr_groups[] = {
        NULL,
 };
 
-static void rapl_cpu_exit(int cpu)
+static int rapl_cpu_offline(unsigned int cpu)
 {
        struct rapl_pmu *pmu = cpu_to_rapl_pmu(cpu);
        int target;
 
        /* Check if exiting cpu is used for collecting rapl events */
        if (!cpumask_test_and_clear_cpu(cpu, &rapl_cpu_mask))
-               return;
+               return 0;
 
        pmu->cpu = -1;
        /* Find a new cpu to collect rapl events */
@@ -574,9 +574,10 @@ static void rapl_cpu_exit(int cpu)
                pmu->cpu = target;
                perf_pmu_migrate_context(pmu->pmu, cpu, target);
        }
+       return 0;
 }
 
-static void rapl_cpu_init(int cpu)
+static int rapl_cpu_online(unsigned int cpu)
 {
        struct rapl_pmu *pmu = cpu_to_rapl_pmu(cpu);
        int target;
@@ -587,13 +588,14 @@ static void rapl_cpu_init(int cpu)
         */
        target = cpumask_any_and(&rapl_cpu_mask, topology_core_cpumask(cpu));
        if (target < nr_cpu_ids)
-               return;
+               return 0;
 
        cpumask_set_cpu(cpu, &rapl_cpu_mask);
        pmu->cpu = cpu;
+       return 0;
 }
 
-static int rapl_cpu_prepare(int cpu)
+static int rapl_cpu_prepare(unsigned int cpu)
 {
        struct rapl_pmu *pmu = cpu_to_rapl_pmu(cpu);
 
@@ -614,33 +616,6 @@ static int rapl_cpu_prepare(int cpu)
        return 0;
 }
 
-static int rapl_cpu_notifier(struct notifier_block *self,
-                            unsigned long action, void *hcpu)
-{
-       unsigned int cpu = (long)hcpu;
-
-       switch (action & ~CPU_TASKS_FROZEN) {
-       case CPU_UP_PREPARE:
-               rapl_cpu_prepare(cpu);
-               break;
-
-       case CPU_DOWN_FAILED:
-       case CPU_ONLINE:
-               rapl_cpu_init(cpu);
-               break;
-
-       case CPU_DOWN_PREPARE:
-               rapl_cpu_exit(cpu);
-               break;
-       }
-       return NOTIFY_OK;
-}
-
-static struct notifier_block rapl_cpu_nb = {
-       .notifier_call  = rapl_cpu_notifier,
-       .priority       = CPU_PRI_PERF + 1,
-};
-
 static int rapl_check_hw_unit(bool apply_quirk)
 {
        u64 msr_rapl_power_unit_bits;
@@ -691,24 +666,6 @@ static void __init rapl_advertise(void)
        }
 }
 
-static int __init rapl_prepare_cpus(void)
-{
-       unsigned int cpu, pkg;
-       int ret;
-
-       for_each_online_cpu(cpu) {
-               pkg = topology_logical_package_id(cpu);
-               if (rapl_pmus->pmus[pkg])
-                       continue;
-
-               ret = rapl_cpu_prepare(cpu);
-               if (ret)
-                       return ret;
-               rapl_cpu_init(cpu);
-       }
-       return 0;
-}
-
 static void cleanup_rapl_pmus(void)
 {
        int i;
@@ -835,35 +792,44 @@ static int __init rapl_pmu_init(void)
        if (ret)
                return ret;
 
-       cpu_notifier_register_begin();
+       /*
+        * Install callbacks. Core will call them for each online cpu.
+        */
 
-       ret = rapl_prepare_cpus();
+       ret = cpuhp_setup_state(CPUHP_PERF_X86_RAPL_PREP, "PERF_X86_RAPL_PREP",
+                               rapl_cpu_prepare, NULL);
        if (ret)
                goto out;
 
+       ret = cpuhp_setup_state(CPUHP_AP_PERF_X86_RAPL_ONLINE,
+                               "AP_PERF_X86_RAPL_ONLINE",
+                               rapl_cpu_online, rapl_cpu_offline);
+       if (ret)
+               goto out1;
+
        ret = perf_pmu_register(&rapl_pmus->pmu, "power", -1);
        if (ret)
-               goto out;
+               goto out2;
 
-       __register_cpu_notifier(&rapl_cpu_nb);
-       cpu_notifier_register_done();
        rapl_advertise();
        return 0;
 
+out2:
+       cpuhp_remove_state(CPUHP_AP_PERF_X86_RAPL_ONLINE);
+out1:
+       cpuhp_remove_state(CPUHP_PERF_X86_RAPL_PREP);
 out:
        pr_warn("Initialization failed (%d), disabled\n", ret);
        cleanup_rapl_pmus();
-       cpu_notifier_register_done();
        return ret;
 }
 module_init(rapl_pmu_init);
 
 static void __exit intel_rapl_exit(void)
 {
-       cpu_notifier_register_begin();
-       __unregister_cpu_notifier(&rapl_cpu_nb);
+       cpuhp_remove_state_nocalls(CPUHP_AP_PERF_X86_RAPL_ONLINE);
+       cpuhp_remove_state_nocalls(CPUHP_PERF_X86_RAPL_PREP);
        perf_pmu_unregister(&rapl_pmus->pmu);
        cleanup_rapl_pmus();
-       cpu_notifier_register_done();
 }
 module_exit(intel_rapl_exit);

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 46720197b307adb4b66422c26db7f1028632614a..06d77fd0fda3146d915eb8f27e4405c288fa9d66 100644 (file)
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -8,6 +8,7 @@ enum cpuhp_state {
        CPUHP_PERF_X86_PREPARE,
        CPUHP_PERF_X86_UNCORE_PREP,
        CPUHP_PERF_X86_AMD_UNCORE_PREP,
+       CPUHP_PERF_X86_RAPL_PREP,
        CPUHP_NOTIFY_PREPARE,
        CPUHP_BRINGUP_CPU,
        CPUHP_AP_IDLE_DEAD,
@@ -34,6 +35,7 @@ enum cpuhp_state {
        CPUHP_AP_PERF_X86_ONLINE,
        CPUHP_AP_PERF_X86_UNCORE_ONLINE,
        CPUHP_AP_PERF_X86_AMD_UNCORE_ONLINE,
+       CPUHP_AP_PERF_X86_RAPL_ONLINE,
        CPUHP_AP_NOTIFY_ONLINE,
        CPUHP_AP_ONLINE_DYN,
        CPUHP_AP_ONLINE_DYN_END         = CPUHP_AP_ONLINE_DYN + 30,