#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>
EXPORT_SYMBOL(unregister_cpu_notifier);
#ifdef CONFIG_HOTPLUG_CPU
-static inline void check_for_tasks(int cpu, struct task_struct *k)
+static inline void check_for_tasks(int cpu)
{
struct task_struct *p;
write_lock_irq(&tasklist_lock);
for_each_process(p) {
- if (task_cpu(p) == cpu && p != k)
- printk(KERN_WARNING "Task %s is on cpu %d\n",
- p->comm, cpu);
+ 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)
{
if (err < 0)
cpu_set(smp_processor_id(), cpu_online_map);
else
- /* Everyone else gets kicked off. */
- migrate_all_tasks();
+ /* 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;
}
{
int err;
struct task_struct *p;
+ cpumask_t old_allowed, tmp;
if ((err = lock_cpu_hotplug_interruptible()) != 0)
return err;
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;
+ cpu_clear(cpu, tmp);
+ set_cpus_allowed(current, tmp);
+
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;
+ goto out_allowed;
}
if (cpu_online(cpu))
goto out_thread;
- check_for_tasks(cpu, p);
-
/* Wait for it to sleep (leaving idle task). */
while (!idle_cpu(cpu))
yield();
__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)
== NOTIFY_BAD)
BUG();
- cpu_run_sbin_hotplug(cpu, "offline");
+ check_for_tasks(cpu);
out_thread:
err = kthread_stop(p);
+out_allowed:
+ set_cpus_allowed(current, old_allowed);
out:
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)
if ((ret = down_interruptible(&cpucontrol)) != 0)
return ret;
- if (cpu_online(cpu)) {
+ if (cpu_online(cpu) || !cpu_present(cpu)) {
ret = -EINVAL;
goto out;
}