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authorThomas Gleixner <tglx@linutronix.de>2016-02-26 18:43:25 +0000
committerThomas Gleixner <tglx@linutronix.de>2016-03-01 20:36:53 +0100
commit984581728eb4b2e10baed3d606f85a119795b207 (patch)
tree80184859a0464bd3265ec7d22430afe50766268b
parentba997462435f48ad1501320e9da8770fd40c59b1 (diff)
cpu/hotplug: Split out cpu down functions
Split cpu_down in separate functions in preparation for state machine conversion. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: Rik van Riel <riel@redhat.com> Cc: Rafael Wysocki <rafael.j.wysocki@intel.com> Cc: "Srivatsa S. Bhat" <srivatsa@mit.edu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Tejun Heo <tj@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Turner <pjt@google.com> Link: http://lkml.kernel.org/r/20160226182340.511796562@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r--kernel/cpu.c83
1 files changed, 53 insertions, 30 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 15a413639abc..0b5d2596f3ec 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -266,11 +266,6 @@ static int bringup_cpu(unsigned int cpu)
}
#ifdef CONFIG_HOTPLUG_CPU
-
-static void cpu_notify_nofail(unsigned long val, unsigned int cpu)
-{
- BUG_ON(cpu_notify(val, cpu));
-}
EXPORT_SYMBOL(register_cpu_notifier);
EXPORT_SYMBOL(__register_cpu_notifier);
@@ -353,6 +348,25 @@ static inline void check_for_tasks(int dead_cpu)
read_unlock(&tasklist_lock);
}
+static void cpu_notify_nofail(unsigned long val, unsigned int cpu)
+{
+ BUG_ON(cpu_notify(val, cpu));
+}
+
+static int notify_down_prepare(unsigned int cpu)
+{
+ int err, nr_calls = 0;
+
+ err = __cpu_notify(CPU_DOWN_PREPARE, cpu, -1, &nr_calls);
+ if (err) {
+ nr_calls--;
+ __cpu_notify(CPU_DOWN_FAILED, cpu, nr_calls, NULL);
+ pr_warn("%s: attempt to take down CPU %u failed\n",
+ __func__, cpu);
+ }
+ return err;
+}
+
/* Take this CPU down. */
static int take_cpu_down(void *_param)
{
@@ -371,29 +385,9 @@ static int take_cpu_down(void *_param)
return 0;
}
-/* Requires cpu_add_remove_lock to be held */
-static int _cpu_down(unsigned int cpu, int tasks_frozen)
+static int takedown_cpu(unsigned int cpu)
{
- int err, nr_calls = 0;
-
- if (num_online_cpus() == 1)
- return -EBUSY;
-
- if (!cpu_online(cpu))
- return -EINVAL;
-
- cpu_hotplug_begin();
-
- cpuhp_tasks_frozen = tasks_frozen;
-
- err = __cpu_notify(CPU_DOWN_PREPARE, cpu, -1, &nr_calls);
- if (err) {
- nr_calls--;
- __cpu_notify(CPU_DOWN_FAILED, cpu, nr_calls, NULL);
- pr_warn("%s: attempt to take down CPU %u failed\n",
- __func__, cpu);
- goto out_release;
- }
+ int err;
/*
* By now we've cleared cpu_active_mask, wait for all preempt-disabled
@@ -426,7 +420,7 @@ static int _cpu_down(unsigned int cpu, int tasks_frozen)
/* CPU didn't die: tell everyone. Can't complain. */
cpu_notify_nofail(CPU_DOWN_FAILED, cpu);
irq_unlock_sparse();
- goto out_release;
+ return err;
}
BUG_ON(cpu_online(cpu));
@@ -449,11 +443,40 @@ static int _cpu_down(unsigned int cpu, int tasks_frozen)
/* This actually kills the CPU. */
__cpu_die(cpu);
- /* CPU is completely dead: tell everyone. Too late to complain. */
tick_cleanup_dead_cpu(cpu);
- cpu_notify_nofail(CPU_DEAD, cpu);
+ return 0;
+}
+static int notify_dead(unsigned int cpu)
+{
+ cpu_notify_nofail(CPU_DEAD, cpu);
check_for_tasks(cpu);
+ return 0;
+}
+
+/* Requires cpu_add_remove_lock to be held */
+static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
+{
+ int err;
+
+ if (num_online_cpus() == 1)
+ return -EBUSY;
+
+ if (!cpu_online(cpu))
+ return -EINVAL;
+
+ cpu_hotplug_begin();
+
+ cpuhp_tasks_frozen = tasks_frozen;
+
+ err = notify_down_prepare(cpu);
+ if (err)
+ goto out_release;
+ err = takedown_cpu(cpu);
+ if (err)
+ goto out_release;
+
+ notify_dead(cpu);
out_release:
cpu_hotplug_done();