linux-kernel - [tip:smp/hotplug] xtensa/perf: Convert the hotplug notifier to state machine callbacks

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Date:	Tue, 19 Jul 2016 00:09:54 -0700
From:	tip-bot for Sebastian Andrzej Siewior <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	peterz@...radead.org, tglx@...utronix.de, hpa@...or.com,
	torvalds@...ux-foundation.org, chris@...kel.net,
	alexander.shishkin@...ux.intel.com, mingo@...nel.org,
	anna-maria@...utronix.de, jcmvbkbc@...il.com, acme@...nel.org,
	linux-kernel@...r.kernel.org, bigeasy@...utronix.de
Subject: [tip:smp/hotplug] xtensa/perf: Convert the hotplug notifier to
 state machine callbacks

Commit-ID:  25a77b55e74c46c79f838a97e782a45c33588ca6
Gitweb:     http://git.kernel.org/tip/25a77b55e74c46c79f838a97e782a45c33588ca6
Author:     Sebastian Andrzej Siewior <bigeasy@...utronix.de>
AuthorDate: Wed, 13 Jul 2016 17:16:26 +0000
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Thu, 14 Jul 2016 09:34:41 +0200

xtensa/perf: Convert the hotplug notifier to state machine callbacks

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

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@...utronix.de>
Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Chris Zankel <chris@...kel.net>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Max Filippov <jcmvbkbc@...il.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: linux-xtensa@...ux-xtensa.org
Cc: rt@...utronix.de
Link: http://lkml.kernel.org/r/20160713153334.852575891@linutronix.de
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/xtensa/kernel/perf_event.c | 26 +++++++++-----------------
 include/linux/cpuhotplug.h      |  1 +
 2 files changed, 10 insertions(+), 17 deletions(-)

diff --git a/arch/xtensa/kernel/perf_event.c b/arch/xtensa/kernel/perf_event.c
index ef90479..0fecc8a 100644
--- a/arch/xtensa/kernel/perf_event.c
+++ b/arch/xtensa/kernel/perf_event.c
@@ -404,7 +404,7 @@ static struct pmu xtensa_pmu = {
 	.read = xtensa_pmu_read,
 };
 
-static void xtensa_pmu_setup(void)
+static int xtensa_pmu_setup(int cpu)
 {
 	unsigned i;
 
@@ -413,21 +413,7 @@ static void xtensa_pmu_setup(void)
 		set_er(0, XTENSA_PMU_PMCTRL(i));
 		set_er(get_er(XTENSA_PMU_PMSTAT(i)), XTENSA_PMU_PMSTAT(i));
 	}
-}
-
-static int xtensa_pmu_notifier(struct notifier_block *self,
-			       unsigned long action, void *data)
-{
-	switch (action & ~CPU_TASKS_FROZEN) {
-	case CPU_STARTING:
-		xtensa_pmu_setup();
-		break;
-
-	default:
-		break;
-	}
-
-	return NOTIFY_OK;
+	return 0;
 }
 
 static int __init xtensa_pmu_init(void)
@@ -435,7 +421,13 @@ static int __init xtensa_pmu_init(void)
 	int ret;
 	int irq = irq_create_mapping(NULL, XCHAL_PROFILING_INTERRUPT);
 
-	perf_cpu_notifier(xtensa_pmu_notifier);
+	ret = cpuhp_setup_state(CPUHP_AP_PERF_XTENSA_STARTING,
+				"AP_PERF_XTENSA_STARTING", xtensa_pmu_setup,
+				NULL);
+	if (ret) {
+		pr_err("xtensa_pmu: failed to register CPU-hotplug.\n");
+		return ret;
+	}
 #if XTENSA_FAKE_NMI
 	enable_irq(irq);
 #else
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 2ee3c0e..f187c46 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -30,6 +30,7 @@ enum cpuhp_state {
 	CPUHP_AP_PERF_X86_AMD_IBS_STARTING,
 	CPUHP_AP_PERF_X86_CQM_STARTING,
 	CPUHP_AP_PERF_X86_CSTATE_STARTING,
+	CPUHP_AP_PERF_XTENSA_STARTING,
 	CPUHP_AP_NOTIFY_STARTING,
 	CPUHP_AP_ONLINE,
 	CPUHP_TEARDOWN_CPU,