Merge master.kernel.org:/home/davem/BK/sched-2.5

into penguin.transmeta.com:/home/penguin/torvalds/repositories/kernel/linux

kernel/sched.c

@@ -140,6 +140,7 @@ struct prio_array {
  */
 struct runqueue {
 	spinlock_t lock;
+	spinlock_t frozen;
 	unsigned long nr_running, nr_switches, expired_timestamp;
 	task_t *curr, *idle;
 	prio_array_t *active, *expired, arrays[2];
@@ -400,7 +401,7 @@ void sched_exit(task_t * p)
 #if CONFIG_SMP || CONFIG_PREEMPT
 asmlinkage void schedule_tail(void)
 {
-	spin_unlock_irq(&this_rq()->lock);
+	spin_unlock_irq(&this_rq()->frozen);
 }
 #endif
 
@@ -518,12 +519,14 @@ static void load_balance(runqueue_t *this_rq, int idle)
 	busiest = NULL;
 	max_load = 1;
 	for (i = 0; i < smp_num_cpus; i++) {
-		rq_src = cpu_rq(cpu_logical_map(i));
-		if (idle || (rq_src->nr_running < this_rq->prev_nr_running[i]))
+		int logical = cpu_logical_map(i);
+
+		rq_src = cpu_rq(logical);
+		if (idle || (rq_src->nr_running < this_rq->prev_nr_running[logical]))
 			load = rq_src->nr_running;
 		else
-			load = this_rq->prev_nr_running[i];
-		this_rq->prev_nr_running[i] = rq_src->nr_running;
+			load = this_rq->prev_nr_running[logical];
+		this_rq->prev_nr_running[logical] = rq_src->nr_running;
 
 		if ((load > max_load) && (rq_src != this_rq)) {
 			busiest = rq_src;
@@ -590,7 +593,7 @@ static void load_balance(runqueue_t *this_rq, int idle)
 #define CAN_MIGRATE_TASK(p,rq,this_cpu)					\
 	((jiffies - (p)->sleep_timestamp > cache_decay_ticks) &&	\
 		((p) != (rq)->curr) &&					\
-			(tmp->cpus_allowed & (1 << (this_cpu))))
+			((p)->cpus_allowed & (1 << (this_cpu))))
 
 	if (!CAN_MIGRATE_TASK(tmp, busiest, this_cpu)) {
 		curr = curr->next;
@@ -808,16 +811,22 @@ asmlinkage void schedule(void)
 	if (likely(prev != next)) {
 		rq->nr_switches++;
 		rq->curr = next;
+		spin_lock(&rq->frozen);
+		spin_unlock(&rq->lock);
+
 		context_switch(prev, next);
+
 		/*
 		 * The runqueue pointer might be from another CPU
 		 * if the new task was last running on a different
 		 * CPU - thus re-load it.
 		 */
-		barrier();
+		mb();
 		rq = this_rq();
-	}
+		spin_unlock_irq(&rq->frozen);
+	} else {
 		spin_unlock_irq(&rq->lock);
+	}
 
 	reacquire_kernel_lock(current);
 	preempt_enable_no_resched();
@@ -1463,6 +1472,7 @@ void __init sched_init(void)
 		rq->active = rq->arrays;
 		rq->expired = rq->arrays + 1;
 		spin_lock_init(&rq->lock);
+		spin_lock_init(&rq->frozen);
 		INIT_LIST_HEAD(&rq->migration_queue);
 
 		for (j = 0; j < 2; j++) {
@@ -1649,19 +1659,31 @@ static int migration_thread(void * unused)
 
 void __init migration_init(void)
 {
+	unsigned long tmp, orig_cache_decay_ticks;
 	int cpu;
 
-	for (cpu = 0; cpu < smp_num_cpus; cpu++)
+	tmp = 0;
+	for (cpu = 0; cpu < smp_num_cpus; cpu++) {
 		if (kernel_thread(migration_thread, NULL,
 				CLONE_FS | CLONE_FILES | CLONE_SIGNAL) < 0)
 			BUG();
+		tmp |= (1UL << cpu_logical_map(cpu));
+	}
+
+	migration_mask = tmp;
 
-	migration_mask = (1 << smp_num_cpus) - 1;
+	orig_cache_decay_ticks = cache_decay_ticks;
+	cache_decay_ticks = 0;
 
-	for (cpu = 0; cpu < smp_num_cpus; cpu++)
-		while (!cpu_rq(cpu)->migration_thread)
+	for (cpu = 0; cpu < smp_num_cpus; cpu++) {
+		int logical = cpu_logical_map(cpu);
+
+		while (!cpu_rq(logical)->migration_thread)
 			schedule_timeout(2);
+	}
 	if (migration_mask)
 		BUG();
+
+	cache_decay_ticks = orig_cache_decay_ticks;
 }
 #endif