Commit-ID: 984581728eb4b2e10baed3d606f85a119795b207
Gitweb: http://git.kernel.org/tip/984581728eb4b2e10baed3d606f85a119795b207
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Fri, 26 Feb 2016 18:43:25 +0000
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Tue, 1 Mar 2016 20:36:53 +0100
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@xxxxxxxxxxxxx>
Cc: linux-arch@xxxxxxxxxxxxxxx
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Rafael Wysocki <rafael.j.wysocki@xxxxxxxxx>
Cc: "Srivatsa S. Bhat" <srivatsa@xxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>
Cc: Sebastian Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Paul McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Paul Turner <pjt@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/20160226182340.511796562@xxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
kernel/cpu.c | 83 ++++++++++++++++++++++++++++++++++++++----------------------
1 file changed, 53 insertions(+), 30 deletions(-)
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 15a4136..0b5d259 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();
--
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