Move the functions which need to run on the hotplugged processor into
a state machine array and let the code iterate through these functions.
In a later state, this will grow synchronization points between the
control processor and the hotplugged processor, so we can move the
various architecture implementations of the synchronizations to the
core.
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
---
include/linux/cpuhotplug.h | 4 ++
kernel/cpu.c | 70 +++++++++++++++++++++++++++++++++++----------
2 files changed, 59 insertions(+), 15 deletions(-)
Index: linux-2.6/include/linux/cpuhotplug.h
===================================================================
--- linux-2.6.orig/include/linux/cpuhotplug.h
+++ linux-2.6/include/linux/cpuhotplug.h
@@ -7,6 +7,10 @@ enum cpuhp_states {
CPUHP_NOTIFY_PREPARE,
CPUHP_NOTIFY_DEAD,
CPUHP_BRINGUP_CPU,
+ CPUHP_AP_OFFLINE,
+ CPUHP_AP_NOTIFY_STARTING,
+ CPUHP_AP_NOTIFY_DYING,
+ CPUHP_AP_MAX,
CPUHP_TEARDOWN_CPU,
CPUHP_PERCPU_THREADS,
CPUHP_NOTIFY_ONLINE,
Index: linux-2.6/kernel/cpu.c
===================================================================
--- linux-2.6.orig/kernel/cpu.c
+++ linux-2.6/kernel/cpu.c
@@ -32,6 +32,7 @@ struct cpuhp_step {
};
static struct cpuhp_step cpuhp_bp_states[];
+static struct cpuhp_step cpuhp_ap_states[];
#ifdef CONFIG_SMP
/* Serializes the updates to cpu_online_mask, cpu_present_mask */
@@ -216,6 +217,12 @@ static int bringup_cpu(unsigned int cpu)
return 0;
}
+static int notify_starting(unsigned int cpu)
+{
+ cpu_notify(CPU_STARTING, cpu);
+ return 0;
+}
+
#ifdef CONFIG_HOTPLUG_CPU
EXPORT_SYMBOL(register_cpu_notifier);
@@ -303,17 +310,26 @@ static int notify_down_prepare(unsigned
return err;
}
+static int notify_dying(unsigned int cpu)
+{
+ cpu_notify(CPU_DYING, cpu);
+ return 0;
+}
+
/* Take this CPU down. */
static int __ref take_cpu_down(void *_param)
{
- int err, cpu = smp_processor_id();
+ int step, err, cpu = smp_processor_id();
/* Ensure this CPU doesn't handle any more interrupts. */
err = __cpu_disable();
if (err < 0)
return err;
- cpu_notify(CPU_DYING, cpu);
+ for (step = CPUHP_AP_MAX; step >= CPUHP_AP_OFFLINE; step--) {
+ if (cpuhp_ap_states[step].teardown)
+ cpuhp_ap_states[step].teardown(cpu);
+ }
/* Park the stopper thread */
kthread_park(current);
return 0;
@@ -357,6 +373,7 @@ static int notify_dead(unsigned int cpu)
#define notify_down_prepare NULL
#define takedown_cpu NULL
#define notify_dead NULL
+#define notify_dying NULL
#endif
#ifdef CONFIG_HOTPLUG_CPU
@@ -429,6 +446,24 @@ out:
EXPORT_SYMBOL(cpu_down);
#endif /*CONFIG_HOTPLUG_CPU*/
+/**
+ * notify_cpu_starting(cpu) - call the CPU_STARTING notifiers
+ * @cpu: cpu that just started
+ *
+ * This function calls the cpu_chain notifiers with CPU_STARTING.
+ * It must be called by the arch code on the new cpu, before the new cpu
+ * enables interrupts and before the "boot" cpu returns from __cpu_up().
+ */
+void notify_cpu_starting(unsigned int cpu)
+{
+ int step;
+
+ for (step = CPUHP_AP_OFFLINE; step < CPUHP_AP_MAX; step++) {
+ if (cpuhp_ap_states[step].startup)
+ cpuhp_ap_states[step].startup(cpu);
+ }
+}
+
static void undo_cpu_up(unsigned int cpu, int step)
{
while (step--) {
@@ -703,19 +738,6 @@ core_initcall(cpu_hotplug_pm_sync_init);
#endif /* CONFIG_PM_SLEEP_SMP */
-/**
- * notify_cpu_starting(cpu) - call the CPU_STARTING notifiers
- * @cpu: cpu that just started
- *
- * This function calls the cpu_chain notifiers with CPU_STARTING.
- * It must be called by the arch code on the new cpu, before the new cpu
- * enables interrupts and before the "boot" cpu returns from __cpu_up().
- */
-void __cpuinit notify_cpu_starting(unsigned int cpu)
-{
- cpu_notify(CPU_STARTING, cpu);
-}
-
#endif /* CONFIG_SMP */
/* Boot processor state steps */
@@ -764,6 +786,24 @@ static struct cpuhp_step cpuhp_bp_states
},
};
+/* Application processor state steps */
+static struct cpuhp_step cpuhp_ap_states[] = {
+#ifdef CONFIG_SMP
+ [CPUHP_AP_NOTIFY_STARTING] = {
+ .startup = notify_starting,
+ .teardown = NULL,
+ },
+ [CPUHP_AP_NOTIFY_DYING] = {
+ .startup = NULL,
+ .teardown = notify_dying,
+ },
+#endif
+ [CPUHP_MAX] = {
+ .startup = NULL,
+ .teardown = NULL,
+ },
+};
+
/*
* cpu_bit_bitmap[] is a special, "compressed" data structure that
* represents all NR_CPUS bits binary values of 1<<nr.
--
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