sched: Simplify cpu-hot-unplug task migration

[pandora-kernel.git] / kernel / cpu.c

diff --git a/kernel/cpu.c b/kernel/cpu.c
index f6e726f..8615aa6 100644 (file)
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -189,7 +189,6 @@ static inline void check_for_tasks(int cpu)
 }
 
 struct take_cpu_down_param {
-       struct task_struct *caller;
        unsigned long mod;
        void *hcpu;
 };
@@ -208,11 +207,6 @@ static int __ref take_cpu_down(void *_param)
 
        cpu_notify(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();
        return 0;
 }
 
@@ -223,7 +217,6 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
        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,
        };
@@ -253,9 +246,12 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
        }
        BUG_ON(cpu_online(cpu));
 
-       /* Wait for it to sleep (leaving idle task). */
-       while (!idle_cpu(cpu))
-               yield();
+       /*
+        * The migration_call() CPU_DYING callback will have removed all
+        * runnable tasks from the cpu, there's only the idle task left now
+        * that the migration thread is done doing the stop_machine thing.
+        */
+       BUG_ON(!idle_cpu(cpu));
 
        /* This actually kills the CPU. */
        __cpu_die(cpu);