sched/deadline: Split cpudl_set() into cpudl_set() and cpudl_clear()

These 2 exercise independent code paths and need different arguments.

After this change, you call:

  cpudl_clear(cp, cpu);
  cpudl_set(cp, cpu, dl);

instead of:

  cpudl_set(cp, cpu, 0 /* dl */, 0 /* is_valid */);
  cpudl_set(cp, cpu, dl, 1 /* is_valid */);

Signed-off-by: Tommaso Cucinotta <tommaso.cucinotta@sssup.it>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Luca Abeni <luca.abeni@unitn.it>
Reviewed-by: Juri Lelli <juri.lelli@arm.com>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-dl@retis.sssup.it
Link: http://lkml.kernel.org/r/1471184828-12644-4-git-send-email-tommaso.cucinotta@sssup.it
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kernel/sched/cpudeadline.c

@@ -144,6 +144,45 @@ out:
 	return best_cpu;
 }
 
+/*
+ * cpudl_clear - remove a cpu from the cpudl max-heap
+ * @cp: the cpudl max-heap context
+ * @cpu: the target cpu
+ *
+ * Notes: assumes cpu_rq(cpu)->lock is locked
+ *
+ * Returns: (void)
+ */
+void cpudl_clear(struct cpudl *cp, int cpu)
+{
+	int old_idx, new_cpu;
+	unsigned long flags;
+
+	WARN_ON(!cpu_present(cpu));
+
+	raw_spin_lock_irqsave(&cp->lock, flags);
+
+	old_idx = cp->elements[cpu].idx;
+	if (old_idx == IDX_INVALID) {
+		/*
+		 * Nothing to remove if old_idx was invalid.
+		 * This could happen if a rq_offline_dl is
+		 * called for a CPU without -dl tasks running.
+		 */
+	} else {
+		new_cpu = cp->elements[cp->size - 1].cpu;
+		cp->elements[old_idx].dl = cp->elements[cp->size - 1].dl;
+		cp->elements[old_idx].cpu = new_cpu;
+		cp->size--;
+		cp->elements[new_cpu].idx = old_idx;
+		cp->elements[cpu].idx = IDX_INVALID;
+		cpudl_heapify(cp, old_idx);
+
+		cpumask_set_cpu(cpu, cp->free_cpus);
+	}
+	raw_spin_unlock_irqrestore(&cp->lock, flags);
+}
+
 /*
  * cpudl_set - update the cpudl max-heap
  * @cp: the cpudl max-heap context
@@ -154,37 +193,16 @@ out:
  *
  * Returns: (void)
  */
-void cpudl_set(struct cpudl *cp, int cpu, u64 dl, int is_valid)
+void cpudl_set(struct cpudl *cp, int cpu, u64 dl)
 {
-	int old_idx, new_cpu;
+	int old_idx;
 	unsigned long flags;
 
 	WARN_ON(!cpu_present(cpu));
 
 	raw_spin_lock_irqsave(&cp->lock, flags);
+
 	old_idx = cp->elements[cpu].idx;
-	if (!is_valid) {
-		/* remove item */
-		if (old_idx == IDX_INVALID) {
-			/*
-			 * Nothing to remove if old_idx was invalid.
-			 * This could happen if a rq_offline_dl is
-			 * called for a CPU without -dl tasks running.
-			 */
-			goto out;
-		}
-		new_cpu = cp->elements[cp->size - 1].cpu;
-		cp->elements[old_idx].dl = cp->elements[cp->size - 1].dl;
-		cp->elements[old_idx].cpu = new_cpu;
-		cp->size--;
-		cp->elements[new_cpu].idx = old_idx;
-		cp->elements[cpu].idx = IDX_INVALID;
-		cpudl_heapify(cp, old_idx);
-		cpumask_set_cpu(cpu, cp->free_cpus);
-
-		goto out;
-	}
-
 	if (old_idx == IDX_INVALID) {
 		int new_idx = cp->size++;
 		cp->elements[new_idx].dl = dl;
@@ -197,7 +215,6 @@ void cpudl_set(struct cpudl *cp, int cpu, u64 dl, int is_valid)
 		cpudl_heapify(cp, old_idx);
 	}
 
-out:
 	raw_spin_unlock_irqrestore(&cp->lock, flags);
 }
 

kernel/sched/cpudeadline.h

@@ -23,7 +23,8 @@ struct cpudl {
 #ifdef CONFIG_SMP
 int cpudl_find(struct cpudl *cp, struct task_struct *p,
 	       struct cpumask *later_mask);
-void cpudl_set(struct cpudl *cp, int cpu, u64 dl, int is_valid);
+void cpudl_set(struct cpudl *cp, int cpu, u64 dl);
+void cpudl_clear(struct cpudl *cp, int cpu);
 int cpudl_init(struct cpudl *cp);
 void cpudl_set_freecpu(struct cpudl *cp, int cpu);
 void cpudl_clear_freecpu(struct cpudl *cp, int cpu);

kernel/sched/deadline.c

@@ -798,7 +798,7 @@ static void inc_dl_deadline(struct dl_rq *dl_rq, u64 deadline)
 	if (dl_rq->earliest_dl.curr == 0 ||
 	    dl_time_before(deadline, dl_rq->earliest_dl.curr)) {
 		dl_rq->earliest_dl.curr = deadline;
-		cpudl_set(&rq->rd->cpudl, rq->cpu, deadline, 1);
+		cpudl_set(&rq->rd->cpudl, rq->cpu, deadline);
 	}
 }
 
@@ -813,14 +813,14 @@ static void dec_dl_deadline(struct dl_rq *dl_rq, u64 deadline)
 	if (!dl_rq->dl_nr_running) {
 		dl_rq->earliest_dl.curr = 0;
 		dl_rq->earliest_dl.next = 0;
-		cpudl_set(&rq->rd->cpudl, rq->cpu, 0, 0);
+		cpudl_clear(&rq->rd->cpudl, rq->cpu);
 	} else {
 		struct rb_node *leftmost = dl_rq->rb_leftmost;
 		struct sched_dl_entity *entry;
 
 		entry = rb_entry(leftmost, struct sched_dl_entity, rb_node);
 		dl_rq->earliest_dl.curr = entry->deadline;
-		cpudl_set(&rq->rd->cpudl, rq->cpu, entry->deadline, 1);
+		cpudl_set(&rq->rd->cpudl, rq->cpu, entry->deadline);
 	}
 }
 
@@ -1671,7 +1671,7 @@ static void rq_online_dl(struct rq *rq)
 
 	cpudl_set_freecpu(&rq->rd->cpudl, rq->cpu);
 	if (rq->dl.dl_nr_running > 0)
-		cpudl_set(&rq->rd->cpudl, rq->cpu, rq->dl.earliest_dl.curr, 1);
+		cpudl_set(&rq->rd->cpudl, rq->cpu, rq->dl.earliest_dl.curr);
 }
 
 /* Assumes rq->lock is held */
@@ -1680,7 +1680,7 @@ static void rq_offline_dl(struct rq *rq)
 	if (rq->dl.overloaded)
 		dl_clear_overload(rq);
 
-	cpudl_set(&rq->rd->cpudl, rq->cpu, 0, 0);
+	cpudl_clear(&rq->rd->cpudl, rq->cpu);
 	cpudl_clear_freecpu(&rq->rd->cpudl, rq->cpu);
 }