kgdb: gdb "monitor" -> kdb passthrough

[safe/jmp/linux-2.6] / kernel / cpu.c

diff --git a/kernel/cpu.c b/kernel/cpu.c
index b216886..5457775 100644 (file)
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -14,6 +14,7 @@
 #include <linux/kthread.h>
 #include <linux/stop_machine.h>
 #include <linux/mutex.h>
+#include <linux/gfp.h>
 
 #ifdef CONFIG_SMP
 /* Serializes the updates to cpu_online_mask, cpu_present_mask */
@@ -151,18 +152,19 @@ static inline void check_for_tasks(int cpu)
 
        write_lock_irq(&tasklist_lock);
        for_each_process(p) {
-               if (task_cpu(p) == cpu &&
+               if (task_cpu(p) == cpu && p->state == TASK_RUNNING &&
                    (!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 = %x) \n",
-                                p->comm, task_pid_nr(p), cpu,
-                                p->state, p->flags);
+                       printk(KERN_WARNING "Task %s (pid = %d) is on cpu %d "
+                               "(state = %ld, flags = %x)\n",
+                               p->comm, task_pid_nr(p), cpu,
+                               p->state, p->flags);
        }
        write_unlock_irq(&tasklist_lock);
 }
 
 struct take_cpu_down_param {
+       struct task_struct *caller;
        unsigned long mod;
        void *hcpu;
 };
@@ -171,6 +173,7 @@ struct take_cpu_down_param {
 static int __ref take_cpu_down(void *_param)
 {
        struct take_cpu_down_param *param = _param;
+       unsigned int cpu = (unsigned long)param->hcpu;
        int err;
 
        /* Ensure this CPU doesn't handle any more interrupts. */
@@ -181,6 +184,8 @@ static int __ref take_cpu_down(void *_param)
        raw_notifier_call_chain(&cpu_chain, CPU_DYING | param->mod,
                                param->hcpu);
 
+       if (task_cpu(param->caller) == cpu)
+               move_task_off_dead_cpu(cpu, param->caller);
        /* Force idle task to run as soon as we yield: it should
           immediately notice cpu is offline and die quickly. */
        sched_idle_next();
@@ -191,10 +196,10 @@ static int __ref take_cpu_down(void *_param)
 static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
 {
        int err, nr_calls = 0;
-       cpumask_var_t old_allowed;
        void *hcpu = (void *)(long)cpu;
        unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
        struct take_cpu_down_param tcd_param = {
+               .caller = current,
                .mod = mod,
                .hcpu = hcpu,
        };
@@ -205,10 +210,8 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
        if (!cpu_online(cpu))
                return -EINVAL;
 
-       if (!alloc_cpumask_var(&old_allowed, GFP_KERNEL))
-               return -ENOMEM;
-
        cpu_hotplug_begin();
+       set_cpu_active(cpu, false);
        err = __raw_notifier_call_chain(&cpu_chain, CPU_DOWN_PREPARE | mod,
                                        hcpu, -1, &nr_calls);
        if (err == NOTIFY_BAD) {
@@ -223,10 +226,6 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
                goto out_release;
        }
 
-       /* Ensure that we are not runnable on dying cpu */
-       cpumask_copy(old_allowed, &current->cpus_allowed);
-       set_cpus_allowed_ptr(current, cpu_active_mask);
-
        err = __stop_machine(take_cpu_down, &tcd_param, cpumask_of(cpu));
        if (err) {
                set_cpu_active(cpu, true);
@@ -235,7 +234,7 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
                                            hcpu) == NOTIFY_BAD)
                        BUG();
 
-               goto out_allowed;
+               goto out_release;
        }
        BUG_ON(cpu_online(cpu));
 
@@ -253,8 +252,6 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
 
        check_for_tasks(cpu);
 
-out_allowed:
-       set_cpus_allowed_ptr(current, old_allowed);
 out_release:
        cpu_hotplug_done();
        if (!err) {
@@ -262,7 +259,6 @@ out_release:
                                            hcpu) == NOTIFY_BAD)
                        BUG();
        }
-       free_cpumask_var(old_allowed);
        return err;
 }
 
@@ -270,9 +266,6 @@ int __ref cpu_down(unsigned int cpu)
 {
        int err;
 
-       err = stop_machine_create();
-       if (err)
-               return err;
        cpu_maps_update_begin();
 
        if (cpu_hotplug_disabled) {
@@ -280,23 +273,10 @@ int __ref cpu_down(unsigned int cpu)
                goto out;
        }
 
-       set_cpu_active(cpu, false);
-
-       /*
-        * Make sure the all cpus did the reschedule and are not
-        * using stale version of the cpu_active_mask.
-        * This is not strictly necessary becuase stop_machine()
-        * that we run down the line already provides the required
-        * synchronization. But it's really a side effect and we do not
-        * want to depend on the innards of the stop_machine here.
-        */
-       synchronize_sched();
-
        err = _cpu_down(cpu, 0);
 
 out:
        cpu_maps_update_done();
-       stop_machine_destroy();
        return err;
 }
 EXPORT_SYMBOL(cpu_down);
@@ -349,7 +329,7 @@ int __cpuinit cpu_up(unsigned int cpu)
        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);
-#if defined(CONFIG_IA64) || defined(CONFIG_X86_64)
+#if defined(CONFIG_IA64)
                printk(KERN_ERR "please check additional_cpus= boot "
                                "parameter\n");
 #endif
@@ -377,33 +357,22 @@ int disable_nonboot_cpus(void)
 {
        int cpu, first_cpu, error;
 
-       error = stop_machine_create();
-       if (error)
-               return error;
        cpu_maps_update_begin();
        first_cpu = cpumask_first(cpu_online_mask);
-       /* We take down all of the non-boot CPUs in one shot to avoid races
+       /*
+        * We take down all of the non-boot CPUs in one shot to avoid races
         * with the userspace trying to use the CPU hotplug at the same time
         */
        cpumask_clear(frozen_cpus);
 
-       for_each_online_cpu(cpu) {
-               if (cpu == first_cpu)
-                       continue;
-               set_cpu_active(cpu, false);
-       }
-
-       synchronize_sched();
-
        printk("Disabling non-boot CPUs ...\n");
        for_each_online_cpu(cpu) {
                if (cpu == first_cpu)
                        continue;
                error = _cpu_down(cpu, 1);
-               if (!error) {
+               if (!error)
                        cpumask_set_cpu(cpu, frozen_cpus);
-                       printk("CPU%d is down\n", cpu);
-               } else {
+               else {
                        printk(KERN_ERR "Error taking CPU%d down: %d\n",
                                cpu, error);
                        break;
@@ -418,7 +387,6 @@ int disable_nonboot_cpus(void)
                printk(KERN_ERR "Non-boot CPUs are not disabled\n");
        }
        cpu_maps_update_done();
-       stop_machine_destroy();
        return error;
 }