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Commit 77c34ef1 authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Ingo Molnar
Browse files

perf/x86/intel/cstate: Convert Intel CSTATE 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: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarAnna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: kbuild test robot <fengguang.wu@intel.com>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160713153334.184061086@linutronix.de


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent f0704827

arch/x86/events/intel/cstate.c

+15 −36
Original line number Diff line number Diff line
@@ -365,7 +365,7 @@ static int cstate_pmu_event_add(struct perf_event *event, int mode) 
 * Check if exiting cpu is the designated reader. If so migrate the

 * events when there is a valid target available

 */

static void cstate_cpu_exit(int cpu)

static int cstate_cpu_exit(unsigned int cpu)

{

	unsigned int target;
@@ -390,9 +390,10 @@ static void cstate_cpu_exit(int cpu) 
			perf_pmu_migrate_context(&cstate_pkg_pmu, cpu, target);

		}

	}

	return 0;

}



static void cstate_cpu_init(int cpu)

static int cstate_cpu_init(unsigned int cpu)

{

	unsigned int target;
@@ -414,31 +415,10 @@ static void cstate_cpu_init(int cpu) 
				 topology_core_cpumask(cpu));

	if (has_cstate_pkg && target >= nr_cpu_ids)

		cpumask_set_cpu(cpu, &cstate_pkg_cpu_mask);

}



static int cstate_cpu_notifier(struct notifier_block *self,

			       unsigned long action, void *hcpu)

{

	unsigned int cpu = (long)hcpu;



	switch (action & ~CPU_TASKS_FROZEN) {

	case CPU_STARTING:

		cstate_cpu_init(cpu);

		break;

	case CPU_DOWN_PREPARE:

		cstate_cpu_exit(cpu);

		break;

	default:

		break;

	}

	return NOTIFY_OK;

	return 0;

}



static struct notifier_block cstate_cpu_nb = {

	.notifier_call	= cstate_cpu_notifier,

	.priority       = CPU_PRI_PERF + 1,

};



static struct pmu cstate_core_pmu = {

	.attr_groups	= core_attr_groups,

	.name		= "cstate_core",
@@ -599,18 +579,20 @@ static inline void cstate_cleanup(void) 


static int __init cstate_init(void)

{

	int cpu, err;

	int err;



	cpu_notifier_register_begin();

	for_each_online_cpu(cpu)

		cstate_cpu_init(cpu);

	cpuhp_setup_state(CPUHP_AP_PERF_X86_CSTATE_STARTING,

			  "AP_PERF_X86_CSTATE_STARTING", cstate_cpu_init,

			  NULL);

	cpuhp_setup_state(CPUHP_AP_PERF_X86_CSTATE_ONLINE,

			  "AP_PERF_X86_CSTATE_ONLINE", NULL, cstate_cpu_exit);



	if (has_cstate_core) {

		err = perf_pmu_register(&cstate_core_pmu, cstate_core_pmu.name, -1);

		if (err) {

			has_cstate_core = false;

			pr_info("Failed to register cstate core pmu\n");

			goto out;

			return err;

		}

	}
@@ -620,12 +602,10 @@ static int __init cstate_init(void) 
			has_cstate_pkg = false;

			pr_info("Failed to register cstate pkg pmu\n");

			cstate_cleanup();

			goto out;

			return err;

		}

	}

	__register_cpu_notifier(&cstate_cpu_nb);

out:

	cpu_notifier_register_done();



	return err;

}
@@ -651,9 +631,8 @@ module_init(cstate_pmu_init); 


static void __exit cstate_pmu_exit(void)

{

	cpu_notifier_register_begin();

	__unregister_cpu_notifier(&cstate_cpu_nb);

	cpuhp_remove_state_nocalls(CPUHP_AP_PERF_X86_CSTATE_ONLINE);

	cpuhp_remove_state_nocalls(CPUHP_AP_PERF_X86_CSTATE_STARTING);

	cstate_cleanup();

	cpu_notifier_register_done();

}

module_exit(cstate_pmu_exit);

include/linux/cpuhotplug.h

+2 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ enum cpuhp_state { 
	CPUHP_AP_PERF_X86_STARTING,

	CPUHP_AP_PERF_X86_AMD_IBS_STARTING,

	CPUHP_AP_PERF_X86_CQM_STARTING,

	CPUHP_AP_PERF_X86_CSTATE_STARTING,

	CPUHP_AP_NOTIFY_STARTING,

	CPUHP_AP_ONLINE,

	CPUHP_TEARDOWN_CPU,
@@ -38,6 +39,7 @@ enum cpuhp_state { 
	CPUHP_AP_PERF_X86_AMD_UNCORE_ONLINE,

	CPUHP_AP_PERF_X86_RAPL_ONLINE,

	CPUHP_AP_PERF_X86_CQM_ONLINE,

	CPUHP_AP_PERF_X86_CSTATE_ONLINE,

	CPUHP_AP_NOTIFY_ONLINE,

	CPUHP_AP_ONLINE_DYN,

	CPUHP_AP_ONLINE_DYN_END		= CPUHP_AP_ONLINE_DYN + 30,