sched: Replace all_pinned with a generic flags field

Replace the all_pinned argument with a flags field so that we can add
some extra controls throughout that entire call chain.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-33kevm71m924ok1gpxd720v3@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/sched/fair.c

@@ -3131,13 +3131,15 @@ task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
 	return delta < (s64)sysctl_sched_migration_cost;
 }
 
+#define LBF_ALL_PINNED	0x01
+
 /*
  * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
  */
 static
 int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
 		     struct sched_domain *sd, enum cpu_idle_type idle,
-		     int *all_pinned)
+		     int *lb_flags)
 {
 	int tsk_cache_hot = 0;
 	/*
@@ -3150,7 +3152,7 @@ int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
 		schedstat_inc(p, se.statistics.nr_failed_migrations_affine);
 		return 0;
 	}
-	*all_pinned = 0;
+	*lb_flags &= ~LBF_ALL_PINNED;
 
 	if (task_running(rq, p)) {
 		schedstat_inc(p, se.statistics.nr_failed_migrations_running);
@@ -3224,7 +3226,7 @@ move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
 static unsigned long
 balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
 	      unsigned long max_load_move, struct sched_domain *sd,
-	      enum cpu_idle_type idle, int *all_pinned,
+	      enum cpu_idle_type idle, int *lb_flags,
 	      struct cfs_rq *busiest_cfs_rq)
 {
 	int loops = 0, pulled = 0;
@@ -3240,7 +3242,7 @@ balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
 
 		if ((p->se.load.weight >> 1) > rem_load_move ||
 		    !can_migrate_task(p, busiest, this_cpu, sd, idle,
-				      all_pinned))
+				      lb_flags))
 			continue;
 
 		pull_task(busiest, p, this_rq, this_cpu);
@@ -3359,7 +3361,7 @@ static unsigned long
 load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
 		  unsigned long max_load_move,
 		  struct sched_domain *sd, enum cpu_idle_type idle,
-		  int *all_pinned)
+		  int *lb_flags)
 {
 	long rem_load_move = max_load_move;
 	struct cfs_rq *busiest_cfs_rq;
@@ -3383,7 +3385,7 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
 		rem_load = div_u64(rem_load, busiest_h_load + 1);
 
 		moved_load = balance_tasks(this_rq, this_cpu, busiest,
-				rem_load, sd, idle, all_pinned,
+				rem_load, sd, idle, lb_flags,
 				busiest_cfs_rq);
 
 		if (!moved_load)
@@ -3409,10 +3411,10 @@ static unsigned long
 load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
 		  unsigned long max_load_move,
 		  struct sched_domain *sd, enum cpu_idle_type idle,
-		  int *all_pinned)
+		  int *lb_flags)
 {
 	return balance_tasks(this_rq, this_cpu, busiest,
-			max_load_move, sd, idle, all_pinned,
+			max_load_move, sd, idle, lb_flags,
 			&busiest->cfs);
 }
 #endif
@@ -3427,14 +3429,14 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
 static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
 		      unsigned long max_load_move,
 		      struct sched_domain *sd, enum cpu_idle_type idle,
-		      int *all_pinned)
+		      int *lb_flags)
 {
 	unsigned long total_load_moved = 0, load_moved;
 
 	do {
 		load_moved = load_balance_fair(this_rq, this_cpu, busiest,
 				max_load_move - total_load_moved,
-				sd, idle, all_pinned);
+				sd, idle, lb_flags);
 
 		total_load_moved += load_moved;
 
@@ -4439,7 +4441,7 @@ static int load_balance(int this_cpu, struct rq *this_rq,
 			struct sched_domain *sd, enum cpu_idle_type idle,
 			int *balance)
 {
-	int ld_moved, all_pinned = 0, active_balance = 0;
+	int ld_moved, lb_flags = 0, active_balance = 0;
 	struct sched_group *group;
 	unsigned long imbalance;
 	struct rq *busiest;
@@ -4480,11 +4482,11 @@ static int load_balance(int this_cpu, struct rq *this_rq,
 		 * still unbalanced. ld_moved simply stays zero, so it is
 		 * correctly treated as an imbalance.
 		 */
-		all_pinned = 1;
+		lb_flags |= LBF_ALL_PINNED;
 		local_irq_save(flags);
 		double_rq_lock(this_rq, busiest);
 		ld_moved = move_tasks(this_rq, this_cpu, busiest,
-				      imbalance, sd, idle, &all_pinned);
+				      imbalance, sd, idle, &lb_flags);
 		double_rq_unlock(this_rq, busiest);
 		local_irq_restore(flags);
 
@@ -4495,7 +4497,7 @@ static int load_balance(int this_cpu, struct rq *this_rq,
 			resched_cpu(this_cpu);
 
 		/* All tasks on this runqueue were pinned by CPU affinity */
-		if (unlikely(all_pinned)) {
+		if (unlikely(lb_flags & LBF_ALL_PINNED)) {
 			cpumask_clear_cpu(cpu_of(busiest), cpus);
 			if (!cpumask_empty(cpus))
 				goto redo;
@@ -4525,7 +4527,7 @@ static int load_balance(int this_cpu, struct rq *this_rq,
 					tsk_cpus_allowed(busiest->curr))) {
 				raw_spin_unlock_irqrestore(&busiest->lock,
 							    flags);
-				all_pinned = 1;
+				lb_flags |= LBF_ALL_PINNED;
 				goto out_one_pinned;
 			}
 
@@ -4578,7 +4580,8 @@ static int load_balance(int this_cpu, struct rq *this_rq,
 
 out_one_pinned:
 	/* tune up the balancing interval */
-	if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) ||
+	if (((lb_flags & LBF_ALL_PINNED) &&
+			sd->balance_interval < MAX_PINNED_INTERVAL) ||
 			(sd->balance_interval < sd->max_interval))
 		sd->balance_interval *= 2;