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[tip:smp/hotplug] sched/nohz: Convert to hotplug state machine

From tip-bot for Sebastian Andrzej Siewior <tipbot@zytor.com>
Newsgroups linux.kernel
Subject [tip:smp/hotplug] sched/nohz: Convert to hotplug state machine
Date 2016-11-21 17:00 +0100
Message-ID <sFZaG-333-29@gated-at.bofh.it> (permalink)
References <sEzLl-4lB-65@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Commit-ID:  703c96e4971c3d2383d9bf248fa656f154250edc
Gitweb:     http://git.kernel.org/tip/703c96e4971c3d2383d9bf248fa656f154250edc
Author:     Sebastian Andrzej Siewior <bigeasy@linutronix.de>
AuthorDate: Thu, 17 Nov 2016 19:35:34 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Mon, 21 Nov 2016 16:37:07 +0100

sched/nohz: Convert to hotplug state machine

Install the callbacks via the state machine.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: rt@linuxtronix.de
Link: http://lkml.kernel.org/r/20161117183541.8588-14-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

---
 kernel/time/tick-sched.c | 33 ++++++++++++++-------------------
 1 file changed, 14 insertions(+), 19 deletions(-)

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 3bcb61b..71496a2 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -390,24 +390,16 @@ static int __init tick_nohz_full_setup(char *str)
 }
 __setup("nohz_full=", tick_nohz_full_setup);
 
-static int tick_nohz_cpu_down_callback(struct notifier_block *nfb,
-				       unsigned long action,
-				       void *hcpu)
+static int tick_nohz_cpu_down(unsigned int cpu)
 {
-	unsigned int cpu = (unsigned long)hcpu;
-
-	switch (action & ~CPU_TASKS_FROZEN) {
-	case CPU_DOWN_PREPARE:
-		/*
-		 * The boot CPU handles housekeeping duty (unbound timers,
-		 * workqueues, timekeeping, ...) on behalf of full dynticks
-		 * CPUs. It must remain online when nohz full is enabled.
-		 */
-		if (tick_nohz_full_running && tick_do_timer_cpu == cpu)
-			return NOTIFY_BAD;
-		break;
-	}
-	return NOTIFY_OK;
+	/*
+	 * The boot CPU handles housekeeping duty (unbound timers,
+	 * workqueues, timekeeping, ...) on behalf of full dynticks
+	 * CPUs. It must remain online when nohz full is enabled.
+	 */
+	if (tick_nohz_full_running && tick_do_timer_cpu == cpu)
+		return -EBUSY;
+	return 0;
 }
 
 static int tick_nohz_init_all(void)
@@ -428,7 +420,7 @@ static int tick_nohz_init_all(void)
 
 void __init tick_nohz_init(void)
 {
-	int cpu;
+	int cpu, ret;
 
 	if (!tick_nohz_full_running) {
 		if (tick_nohz_init_all() < 0)
@@ -469,7 +461,10 @@ void __init tick_nohz_init(void)
 	for_each_cpu(cpu, tick_nohz_full_mask)
 		context_tracking_cpu_set(cpu);
 
-	cpu_notifier(tick_nohz_cpu_down_callback, 0);
+	ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
+					"kernel/nohz:predown", NULL,
+					tick_nohz_cpu_down);
+	WARN_ON(ret < 0);
 	pr_info("NO_HZ: Full dynticks CPUs: %*pbl.\n",
 		cpumask_pr_args(tick_nohz_full_mask));
 

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Thread

cpu hotplug: convert more drivers (batch #5) Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-17 19:40 +0100
  [PATCH 12/20] net/iucv: Convert to hotplug state machine Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-17 19:40 +0100
    [tip:smp/hotplug] net/iucv: Convert to hotplug state machine tip-bot for Sebastian Andrzej Siewior <tipbot@zytor.com> - 2016-11-21 17:00 +0100
    [tip:smp/hotplug] net/iucv: Convert to hotplug state machine tip-bot for Sebastian Andrzej Siewior <tipbot@zytor.com> - 2016-11-23 00:20 +0100
    Re: [PATCH 12/20] net/iucv: Convert to hotplug state machine Ursula Braun <ubraun@linux.vnet.ibm.com> - 2016-11-23 20:40 +0100
      Re: [PATCH 12/20] net/iucv: Convert to hotplug state machine Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-24 10:20 +0100
        [PATCH 12/20 v2] net/iucv: Convert to hotplug state machine Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-24 15:20 +0100
          [PATCH] net/iucv: use explicit clean up labels in iucv_init() Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-24 17:20 +0100
            [tip:smp/hotplug] net/iucv: Use explicit clean up labels in  iucv_init() tip-bot for Sebastian Andrzej Siewior <tipbot@zytor.com> - 2016-11-24 21:00 +0100
  [PATCH 09/20] powercap/intel rapl: Convert to hotplug state machine Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-17 19:40 +0100
    [tip:smp/hotplug] powercap/intel rapl: Convert to hotplug state  machine tip-bot for Sebastian Andrzej Siewior <tipbot@zytor.com> - 2016-11-21 17:00 +0100
  [PATCH 19/20] x86/oprofile/nmi: Convert to hotplug state machine Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-17 19:40 +0100
    [tip:smp/hotplug] x86/oprofile/nmi: Convert to hotplug state  machine tip-bot for Sebastian Andrzej Siewior <tipbot@zytor.com> - 2016-11-21 17:00 +0100
    [tip:smp/hotplug] x86/oprofile/nmi: Convert to hotplug state  machine tip-bot for Sebastian Andrzej Siewior <tipbot@zytor.com> - 2016-11-22 23:50 +0100
  [PATCH 14/20] arm/bL_switcher: Convert to hotplug state machine Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-17 19:40 +0100
    [tip:smp/hotplug] arm/bL_switcher: Convert to hotplug state machine tip-bot for Sebastian Andrzej Siewior <tipbot@zytor.com> - 2016-11-21 17:00 +0100
    [tip:smp/hotplug] arm/bL_switcher: Convert to hotplug state machine tip-bot for Sebastian Andrzej Siewior <tipbot@zytor.com> - 2016-11-22 23:50 +0100
  [PATCH 13/20] sched/nohz: Convert to hotplug state machine Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-17 19:40 +0100
    [tip:smp/hotplug] sched/nohz: Convert to hotplug state machine tip-bot for Sebastian Andrzej Siewior <tipbot@zytor.com> - 2016-11-21 17:00 +0100
    [tip:smp/hotplug] sched/nohz: Convert to hotplug state machine tip-bot for Sebastian Andrzej Siewior <tipbot@zytor.com> - 2016-11-23 00:20 +0100
  [PATCH 16/20] powerpc/sysfs: Convert to hotplug state machine Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-17 19:40 +0100
    [tip:smp/hotplug] powerpc/sysfs: Convert to hotplug state machine tip-bot for Sebastian Andrzej Siewior <tipbot@zytor.com> - 2016-11-21 17:00 +0100
    [tip:smp/hotplug] powerpc/sysfs: Convert to hotplug state machine tip-bot for Sebastian Andrzej Siewior <tipbot@zytor.com> - 2016-11-22 23:50 +0100
  [PATCH 10/20] powercap/intel_rapl: Cleanup duplicated init code Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-17 19:50 +0100
    [tip:smp/hotplug] powercap/intel_rapl: Cleanup duplicated init code tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-11-21 17:00 +0100
  [PATCH 01/20] x86/mce/therm_throt: Convert to hotplug state machine Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-17 19:50 +0100
    [tip:smp/hotplug] x86/mce/therm_throt: Convert to hotplug state  machine tip-bot for Sebastian Andrzej Siewior <tipbot@zytor.com> - 2016-11-21 16:50 +0100
    [tip:smp/hotplug] x86/mce/therm_throt: Convert to hotplug state  machine tip-bot for Sebastian Andrzej Siewior <tipbot@zytor.com> - 2016-11-22 23:50 +0100
  [PATCH 07/20] pci/xgene-msi: Convert to hotplug state machine Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-17 19:50 +0100
    [tip:smp/hotplug] PCI/xgene-msi: Convert to hotplug state machine tip-bot for Sebastian Andrzej Siewior <tipbot@zytor.com> - 2016-11-21 16:50 +0100
    [tip:smp/hotplug] PCI/xgene-msi: Convert to hotplug state machine tip-bot for Sebastian Andrzej Siewior <tipbot@zytor.com> - 2016-11-23 00:20 +0100
  [PATCH 06/20] hwmon/via-cputemp: Convert to hotplug state machine Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-17 19:50 +0100
    [PATCH 06/20 v2] hwmon/via-cputemp: Convert to hotplug state machine Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-18 16:20 +0100
    Re: [PATCH 06/20] hwmon/via-cputemp: Convert to hotplug state machine Guenter Roeck <linux@roeck-us.net> - 2016-11-23 16:40 +0100
  [PATCH 05/20] hwmon/via-cputemp: Remove pointless CPU check on each CPU Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-17 19:50 +0100
    Re: [05/20] hwmon/via-cputemp: Remove pointless CPU check on each CPU Guenter Roeck <linux@roeck-us.net> - 2016-11-19 18:30 +0100
      Re: [05/20] hwmon/via-cputemp: Remove pointless CPU check on each CPU Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-20 00:00 +0100
        Re: [05/20] hwmon/via-cputemp: Remove pointless CPU check on each CPU Guenter Roeck <linux@roeck-us.net> - 2016-11-20 05:00 +0100
          Re: [05/20] hwmon/via-cputemp: Remove pointless CPU check on each CPU Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-20 21:40 +0100
  [PATCH 08/20] powercap/intel_rapl: Add missing domain data update on hotplug Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-17 19:50 +0100
    [tip:smp/hotplug] powercap/intel_rapl: Add missing domain data  update on hotplug tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-11-21 16:50 +0100
  [PATCH 03/20] x86/msr: Convert to hotplug state machine Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-17 19:50 +0100
    [tip:smp/hotplug] x86/msr: Convert to hotplug state machine tip-bot for Sebastian Andrzej Siewior <tipbot@zytor.com> - 2016-11-21 16:50 +0100
    [tip:smp/hotplug] x86/msr: Convert to hotplug state machine tip-bot for Sebastian Andrzej Siewior <tipbot@zytor.com> - 2016-11-22 23:50 +0100

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