This commit was manufactured by cvs2svn to create branch 'vserver'.

[linux-2.6.git] / kernel / cpu.c

diff --git a/kernel/cpu.c b/kernel/cpu.c
index fcbb0d5..628f4cc 100644 (file)
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -11,7 +11,6 @@
 #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>
@@ -43,46 +42,22 @@ void unregister_cpu_notifier(struct notifier_block *nb)
 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)
 {
@@ -96,8 +71,9 @@ 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;
 }
@@ -106,6 +82,7 @@ int cpu_down(unsigned int cpu)
 {
        int err;
        struct task_struct *p;
+       cpumask_t old_allowed, tmp;
 
        if ((err = lock_cpu_hotplug_interruptible()) != 0)
                return err;
@@ -120,17 +97,35 @@ 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;
+       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();
@@ -139,26 +134,24 @@ int cpu_down(unsigned int cpu)
        __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)
@@ -169,7 +162,7 @@ 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;
        }