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Subject[tip:smp/hotplug] perf/x86/intel/rapl: Convert to hotplug state machine
Commit-ID:  8b5b773d6245138c461b3a3e242339fa50fa9c58
Gitweb: http://git.kernel.org/tip/8b5b773d6245138c461b3a3e242339fa50fa9c58
Author: Richard Cochran <rcochran@linutronix.de>
AuthorDate: Wed, 13 Jul 2016 17:16:15 +0000
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 14 Jul 2016 09:34:34 +0200

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>
---
arch/x86/events/intel/rapl.c | 84 +++++++++++++-------------------------------
include/linux/cpuhotplug.h | 2 ++
2 files changed, 27 insertions(+), 59 deletions(-)

diff --git a/arch/x86/events/intel/rapl.c b/arch/x86/events/intel/rapl.c
index e30eef4..6255ede 100644
--- 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 4672019..06d77fd 100644
--- 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,
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