#include <linux/mutex.h>
#include <linux/gfp.h>
#include <linux/suspend.h>
+#include <linux/lockdep.h>
#include "smpboot.h"
static DEFINE_MUTEX(cpu_add_remove_lock);
/*
- * The following two API's must be used when attempting
- * to serialize the updates to cpu_online_mask, cpu_present_mask.
+ * The following two APIs (cpu_maps_update_begin/done) must be used when
+ * attempting to serialize the updates to cpu_online_mask & cpu_present_mask.
+ * The APIs cpu_notifier_register_begin/done() must be used to protect CPU
+ * hotplug callback (un)registration performed using __register_cpu_notifier()
+ * or __unregister_cpu_notifier().
*/
void cpu_maps_update_begin(void)
{
mutex_lock(&cpu_add_remove_lock);
}
+EXPORT_SYMBOL(cpu_notifier_register_begin);
void cpu_maps_update_done(void)
{
mutex_unlock(&cpu_add_remove_lock);
}
+EXPORT_SYMBOL(cpu_notifier_register_done);
static RAW_NOTIFIER_HEAD(cpu_chain);
* an ongoing cpu hotplug operation.
*/
int refcount;
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ struct lockdep_map dep_map;
+#endif
} cpu_hotplug = {
.active_writer = NULL,
.lock = __MUTEX_INITIALIZER(cpu_hotplug.lock),
.refcount = 0,
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ .dep_map = {.name = "cpu_hotplug.lock" },
+#endif
};
+/* Lockdep annotations for get/put_online_cpus() and cpu_hotplug_begin/end() */
+#define cpuhp_lock_acquire_read() lock_map_acquire_read(&cpu_hotplug.dep_map)
+#define cpuhp_lock_acquire() lock_map_acquire(&cpu_hotplug.dep_map)
+#define cpuhp_lock_release() lock_map_release(&cpu_hotplug.dep_map)
+
void get_online_cpus(void)
{
might_sleep();
if (cpu_hotplug.active_writer == current)
return;
+ cpuhp_lock_acquire_read();
mutex_lock(&cpu_hotplug.lock);
cpu_hotplug.refcount++;
mutex_unlock(&cpu_hotplug.lock);
if (!--cpu_hotplug.refcount && unlikely(cpu_hotplug.active_writer))
wake_up_process(cpu_hotplug.active_writer);
mutex_unlock(&cpu_hotplug.lock);
+ cpuhp_lock_release();
}
EXPORT_SYMBOL_GPL(put_online_cpus);
{
cpu_hotplug.active_writer = current;
+ cpuhp_lock_acquire();
for (;;) {
mutex_lock(&cpu_hotplug.lock);
if (likely(!cpu_hotplug.refcount))
{
cpu_hotplug.active_writer = NULL;
mutex_unlock(&cpu_hotplug.lock);
+ cpuhp_lock_release();
}
/*
return ret;
}
+int __ref __register_cpu_notifier(struct notifier_block *nb)
+{
+ return raw_notifier_chain_register(&cpu_chain, nb);
+}
+
static int __cpu_notify(unsigned long val, void *v, int nr_to_call,
int *nr_calls)
{
BUG_ON(cpu_notify(val, v));
}
EXPORT_SYMBOL(register_cpu_notifier);
+EXPORT_SYMBOL(__register_cpu_notifier);
void __ref unregister_cpu_notifier(struct notifier_block *nb)
{
}
EXPORT_SYMBOL(unregister_cpu_notifier);
+void __ref __unregister_cpu_notifier(struct notifier_block *nb)
+{
+ raw_notifier_chain_unregister(&cpu_chain, nb);
+}
+EXPORT_SYMBOL(__unregister_cpu_notifier);
+
/**
* clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU
* @cpu: a CPU id
__func__, cpu);
goto out_release;
}
+
+ /*
+ * By now we've cleared cpu_active_mask, wait for all preempt-disabled
+ * and RCU users of this state to go away such that all new such users
+ * will observe it.
+ *
+ * For CONFIG_PREEMPT we have preemptible RCU and its sync_rcu() might
+ * not imply sync_sched(), so explicitly call both.
+ *
+ * Do sync before park smpboot threads to take care the rcu boost case.
+ */
+#ifdef CONFIG_PREEMPT
+ synchronize_sched();
+#endif
+ synchronize_rcu();
+
smpboot_park_threads(cpu);
+ /*
+ * So now all preempt/rcu users must observe !cpu_active().
+ */
+
err = __stop_machine(take_cpu_down, &tcd_param, cpumask_of(cpu));
if (err) {
/* CPU didn't die: tell everyone. Can't complain. */
{
int err = 0;
-#ifdef CONFIG_MEMORY_HOTPLUG
- int nid;
- pg_data_t *pgdat;
-#endif
-
if (!cpu_possible(cpu)) {
printk(KERN_ERR "can't online cpu %d because it is not "
"configured as may-hotadd at boot time\n", cpu);
return -EINVAL;
}
-#ifdef CONFIG_MEMORY_HOTPLUG
- nid = cpu_to_node(cpu);
- if (!node_online(nid)) {
- err = mem_online_node(nid);
- if (err)
- return err;
- }
-
- pgdat = NODE_DATA(nid);
- if (!pgdat) {
- printk(KERN_ERR
- "Can't online cpu %d due to NULL pgdat\n", cpu);
- return -ENOMEM;
- }
-
- if (pgdat->node_zonelists->_zonerefs->zone == NULL) {
- mutex_lock(&zonelists_mutex);
- build_all_zonelists(NULL, NULL);
- mutex_unlock(&zonelists_mutex);
- }
-#endif
+ err = try_online_node(cpu_to_node(cpu));
+ if (err)
+ return err;
cpu_maps_update_begin();