#include <linux/unistd.h>
#include <linux/cpu.h>
#include <linux/module.h>
-#include <linux/kmod.h> /* for hotplug_path */
#include <linux/kthread.h>
#include <linux/stop_machine.h>
#include <asm/semaphore.h>
/* This protects CPUs going up and down... */
-DECLARE_MUTEX(cpucontrol);
+static DECLARE_MUTEX(cpucontrol);
static struct notifier_block *cpu_chain;
+#ifdef CONFIG_HOTPLUG_CPU
+static struct task_struct *lock_cpu_hotplug_owner;
+static int lock_cpu_hotplug_depth;
+
+static int __lock_cpu_hotplug(int interruptible)
+{
+ int ret = 0;
+
+ if (lock_cpu_hotplug_owner != current) {
+ if (interruptible)
+ ret = down_interruptible(&cpucontrol);
+ else
+ down(&cpucontrol);
+ }
+
+ /*
+ * Set only if we succeed in locking
+ */
+ if (!ret) {
+ lock_cpu_hotplug_depth++;
+ lock_cpu_hotplug_owner = current;
+ }
+
+ return ret;
+}
+
+void lock_cpu_hotplug(void)
+{
+ __lock_cpu_hotplug(0);
+}
+EXPORT_SYMBOL_GPL(lock_cpu_hotplug);
+
+void unlock_cpu_hotplug(void)
+{
+ if (--lock_cpu_hotplug_depth == 0) {
+ lock_cpu_hotplug_owner = NULL;
+ up(&cpucontrol);
+ }
+}
+EXPORT_SYMBOL_GPL(unlock_cpu_hotplug);
+
+int lock_cpu_hotplug_interruptible(void)
+{
+ return __lock_cpu_hotplug(1);
+}
+EXPORT_SYMBOL_GPL(lock_cpu_hotplug_interruptible);
+#endif /* CONFIG_HOTPLUG_CPU */
+
/* Need to know about CPUs going up/down? */
int register_cpu_notifier(struct notifier_block *nb)
{
int ret;
- if ((ret = down_interruptible(&cpucontrol)) != 0)
+ if ((ret = lock_cpu_hotplug_interruptible()) != 0)
return ret;
ret = notifier_chain_register(&cpu_chain, nb);
- up(&cpucontrol);
+ unlock_cpu_hotplug();
return ret;
}
EXPORT_SYMBOL(register_cpu_notifier);
void unregister_cpu_notifier(struct notifier_block *nb)
{
- down(&cpucontrol);
+ lock_cpu_hotplug();
notifier_chain_unregister(&cpu_chain, nb);
- up(&cpucontrol);
+ unlock_cpu_hotplug();
}
EXPORT_SYMBOL(unregister_cpu_notifier);
write_lock_irq(&tasklist_lock);
for_each_process(p) {
- if (task_cpu(p) == cpu && (p->utime != 0 || p->stime != 0))
+ if (task_cpu(p) == cpu &&
+ (!cputime_eq(p->utime, cputime_zero) ||
+ !cputime_eq(p->stime, cputime_zero)))
printk(KERN_WARNING "Task %s (pid = %d) is on cpu %d\
(state = %ld, flags = %lx) \n",
p->comm, p->pid, cpu, p->state, p->flags);
write_unlock_irq(&tasklist_lock);
}
-/* Notify userspace when a cpu event occurs, by running '/sbin/hotplug
- * cpu' with certain environment variables set. */
-static int cpu_run_sbin_hotplug(unsigned int cpu, const char *action)
-{
- char *argv[3], *envp[5], cpu_str[12], action_str[32];
- int i;
-
- sprintf(cpu_str, "CPU=%d", cpu);
- sprintf(action_str, "ACTION=%s", action);
- /* FIXME: Add DEVPATH. --RR */
-
- i = 0;
- argv[i++] = hotplug_path;
- argv[i++] = "cpu";
- argv[i] = NULL;
-
- i = 0;
- /* minimal command environment */
- envp[i++] = "HOME=/";
- envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
- envp[i++] = cpu_str;
- envp[i++] = action_str;
- envp[i] = NULL;
-
- return call_usermodehelper(argv[0], argv, envp, 0);
-}
-
/* Take this CPU down. */
static int take_cpu_down(void *unused)
{
int err;
- /* Take offline: makes arch_cpu_down somewhat easier. */
- cpu_clear(smp_processor_id(), cpu_online_map);
-
/* Ensure this CPU doesn't handle any more interrupts. */
err = __cpu_disable();
if (err < 0)
- cpu_set(smp_processor_id(), cpu_online_map);
- else
- /* Force idle task to run as soon as we yield: it should
- immediately notice cpu is offline and die quickly. */
- sched_idle_next();
+ return err;
- return err;
+ /* Force idle task to run as soon as we yield: it should
+ immediately notice cpu is offline and die quickly. */
+ sched_idle_next();
+ return 0;
}
int cpu_down(unsigned int cpu)
goto out;
}
+ err = notifier_call_chain(&cpu_chain, CPU_DOWN_PREPARE,
+ (void *)(long)cpu);
+ if (err == NOTIFY_BAD) {
+ printk("%s: attempt to take down CPU %u failed\n",
+ __FUNCTION__, cpu);
+ err = -EINVAL;
+ goto out;
+ }
+
/* Ensure that we are not runnable on dying cpu */
old_allowed = current->cpus_allowed;
tmp = CPU_MASK_ALL;
p = __stop_machine_run(take_cpu_down, NULL, cpu);
if (IS_ERR(p)) {
+ /* CPU didn't die: tell everyone. Can't complain. */
+ if (notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED,
+ (void *)(long)cpu) == NOTIFY_BAD)
+ BUG();
+
err = PTR_ERR(p);
goto out_allowed;
}
__cpu_die(cpu);
/* Move it here so it can run. */
- kthread_bind(p, smp_processor_id());
+ kthread_bind(p, get_cpu());
+ put_cpu();
/* CPU is completely dead: tell everyone. Too late to complain. */
if (notifier_call_chain(&cpu_chain, CPU_DEAD, (void *)(long)cpu)
check_for_tasks(cpu);
- cpu_run_sbin_hotplug(cpu, "offline");
-
out_thread:
err = kthread_stop(p);
out_allowed:
unlock_cpu_hotplug();
return err;
}
-#else
-static inline int cpu_run_sbin_hotplug(unsigned int cpu, const char *action)
-{
- return 0;
-}
#endif /*CONFIG_HOTPLUG_CPU*/
int __devinit cpu_up(unsigned int cpu)
int ret;
void *hcpu = (void *)(long)cpu;
- if ((ret = down_interruptible(&cpucontrol)) != 0)
+ if ((ret = lock_cpu_hotplug_interruptible()) != 0)
return ret;
if (cpu_online(cpu) || !cpu_present(cpu)) {
ret = -EINVAL;
goto out;
}
+
ret = notifier_call_chain(&cpu_chain, CPU_UP_PREPARE, hcpu);
if (ret == NOTIFY_BAD) {
printk("%s: attempt to bring up CPU %u failed\n",
if (ret != 0)
notifier_call_chain(&cpu_chain, CPU_UP_CANCELED, hcpu);
out:
- up(&cpucontrol);
+ unlock_cpu_hotplug();
return ret;
}
git://git.onelab.eu / linux-2.6.git / blobdiff