[patch 16/66] blackfin: perf: Convert hotplug notifier to state machine

From: Anna-Maria Gleixner
Date: Mon Jul 11 2016 - 08:46:36 EST


From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

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

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Steven Miao <realmz6@xxxxxxxxx>
Signed-off-by: Anna-Maria Gleixner <anna-maria@xxxxxxxxxxxxx>
---
arch/blackfin/kernel/perf_event.c | 26 +++++---------------------
include/linux/cpuhotplug.h | 1 +
2 files changed, 6 insertions(+), 21 deletions(-)

--- a/arch/blackfin/kernel/perf_event.c
+++ b/arch/blackfin/kernel/perf_event.c
@@ -453,29 +453,13 @@ static struct pmu pmu = {
.read = bfin_pmu_read,
};

-static void bfin_pmu_setup(int cpu)
+static int bfin_pmu_prepare_cpu(unsigned int cpu)
{
struct cpu_hw_events *cpuhw = &per_cpu(cpu_hw_events, cpu);

+ bfin_write_PFCTL(0);
memset(cpuhw, 0, sizeof(struct cpu_hw_events));
-}
-
-static int
-bfin_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu)
-{
- unsigned int cpu = (long)hcpu;
-
- switch (action & ~CPU_TASKS_FROZEN) {
- case CPU_UP_PREPARE:
- bfin_write_PFCTL(0);
- bfin_pmu_setup(cpu);
- break;
-
- default:
- break;
- }
-
- return NOTIFY_OK;
+ return 0;
}

static int __init bfin_pmu_init(void)
@@ -491,8 +475,8 @@ static int __init bfin_pmu_init(void)

ret = perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
if (!ret)
- perf_cpu_notifier(bfin_pmu_notifier);
-
+ cpuhp_setup_state(CPUHP_PERF_BFIN, "PERF_BFIN",
+ bfin_pmu_prepare_cpu, NULL);
return ret;
}
early_initcall(bfin_pmu_init);
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -9,6 +9,7 @@ enum cpuhp_state {
CPUHP_PERF_X86_UNCORE_PREP,
CPUHP_PERF_X86_AMD_UNCORE_PREP,
CPUHP_PERF_X86_RAPL_PREP,
+ CPUHP_PERF_BFIN,
CPUHP_NOTIFY_PREPARE,
CPUHP_BRINGUP_CPU,
CPUHP_AP_IDLE_DEAD,