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Commit 2161573e authored by Davidlohr Bueso's avatar Davidlohr Bueso Committed by Linus Torvalds
Browse files

sched/deadline: replace earliest dl and rq leftmost caching 

... with the generic rbtree flavor instead. No changes
in semantics whatsoever.

Link: http://lkml.kernel.org/r/20170719014603.19029-9-dave@stgolabs.net


Signed-off-by: default avatarDavidlohr Bueso <dbueso@suse.de>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent bfb06889

kernel/sched/deadline.c

+19 −31
Original line number Diff line number Diff line
@@ -296,7 +296,7 @@ static inline int is_leftmost(struct task_struct *p, struct dl_rq *dl_rq) 
{

	struct sched_dl_entity *dl_se = &p->dl;



	return dl_rq->rb_leftmost == &dl_se->rb_node;

	return dl_rq->root.rb_leftmost == &dl_se->rb_node;

}



void init_dl_bandwidth(struct dl_bandwidth *dl_b, u64 period, u64 runtime)
@@ -320,7 +320,7 @@ void init_dl_bw(struct dl_bw *dl_b) 


void init_dl_rq(struct dl_rq *dl_rq)

{

	dl_rq->rb_root = RB_ROOT;

	dl_rq->root = RB_ROOT_CACHED;



#ifdef CONFIG_SMP

	/* zero means no -deadline tasks */
@@ -328,7 +328,7 @@ void init_dl_rq(struct dl_rq *dl_rq) 


	dl_rq->dl_nr_migratory = 0;

	dl_rq->overloaded = 0;

	dl_rq->pushable_dl_tasks_root = RB_ROOT;

	dl_rq->pushable_dl_tasks_root = RB_ROOT_CACHED;

#else

	init_dl_bw(&dl_rq->dl_bw);

#endif
@@ -410,10 +410,10 @@ static void dec_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) 
static void enqueue_pushable_dl_task(struct rq *rq, struct task_struct *p)

{

	struct dl_rq *dl_rq = &rq->dl;

	struct rb_node **link = &dl_rq->pushable_dl_tasks_root.rb_node;

	struct rb_node **link = &dl_rq->pushable_dl_tasks_root.rb_root.rb_node;

	struct rb_node *parent = NULL;

	struct task_struct *entry;

	int leftmost = 1;

	bool leftmost = true;



	BUG_ON(!RB_EMPTY_NODE(&p->pushable_dl_tasks));
@@ -425,17 +425,16 @@ static void enqueue_pushable_dl_task(struct rq *rq, struct task_struct *p) 
			link = &parent->rb_left;

		else {

			link = &parent->rb_right;

			leftmost = 0;

			leftmost = false;

		}

	}



	if (leftmost) {

		dl_rq->pushable_dl_tasks_leftmost = &p->pushable_dl_tasks;

	if (leftmost)

		dl_rq->earliest_dl.next = p->dl.deadline;

	}



	rb_link_node(&p->pushable_dl_tasks, parent, link);

	rb_insert_color(&p->pushable_dl_tasks, &dl_rq->pushable_dl_tasks_root);

	rb_insert_color_cached(&p->pushable_dl_tasks,

			       &dl_rq->pushable_dl_tasks_root, leftmost);

}



static void dequeue_pushable_dl_task(struct rq *rq, struct task_struct *p)
@@ -445,24 +444,23 @@ static void dequeue_pushable_dl_task(struct rq *rq, struct task_struct *p) 
	if (RB_EMPTY_NODE(&p->pushable_dl_tasks))

		return;



	if (dl_rq->pushable_dl_tasks_leftmost == &p->pushable_dl_tasks) {

	if (dl_rq->pushable_dl_tasks_root.rb_leftmost == &p->pushable_dl_tasks) {

		struct rb_node *next_node;



		next_node = rb_next(&p->pushable_dl_tasks);

		dl_rq->pushable_dl_tasks_leftmost = next_node;

		if (next_node) {

			dl_rq->earliest_dl.next = rb_entry(next_node,

				struct task_struct, pushable_dl_tasks)->dl.deadline;

		}

	}



	rb_erase(&p->pushable_dl_tasks, &dl_rq->pushable_dl_tasks_root);

	rb_erase_cached(&p->pushable_dl_tasks, &dl_rq->pushable_dl_tasks_root);

	RB_CLEAR_NODE(&p->pushable_dl_tasks);

}



static inline int has_pushable_dl_tasks(struct rq *rq)

{

	return !RB_EMPTY_ROOT(&rq->dl.pushable_dl_tasks_root);

	return !RB_EMPTY_ROOT(&rq->dl.pushable_dl_tasks_root.rb_root);

}



static int push_dl_task(struct rq *rq);
@@ -1266,7 +1264,7 @@ static void dec_dl_deadline(struct dl_rq *dl_rq, u64 deadline) 
		dl_rq->earliest_dl.next = 0;

		cpudl_clear(&rq->rd->cpudl, rq->cpu);

	} else {

		struct rb_node *leftmost = dl_rq->rb_leftmost;

		struct rb_node *leftmost = dl_rq->root.rb_leftmost;

		struct sched_dl_entity *entry;



		entry = rb_entry(leftmost, struct sched_dl_entity, rb_node);
@@ -1313,7 +1311,7 @@ void dec_dl_tasks(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) 
static void __enqueue_dl_entity(struct sched_dl_entity *dl_se)

{

	struct dl_rq *dl_rq = dl_rq_of_se(dl_se);

	struct rb_node **link = &dl_rq->rb_root.rb_node;

	struct rb_node **link = &dl_rq->root.rb_root.rb_node;

	struct rb_node *parent = NULL;

	struct sched_dl_entity *entry;

	int leftmost = 1;
@@ -1331,11 +1329,8 @@ static void __enqueue_dl_entity(struct sched_dl_entity *dl_se) 
		}

	}



	if (leftmost)

		dl_rq->rb_leftmost = &dl_se->rb_node;



	rb_link_node(&dl_se->rb_node, parent, link);

	rb_insert_color(&dl_se->rb_node, &dl_rq->rb_root);

	rb_insert_color_cached(&dl_se->rb_node, &dl_rq->root, leftmost);



	inc_dl_tasks(dl_se, dl_rq);

}
@@ -1347,14 +1342,7 @@ static void __dequeue_dl_entity(struct sched_dl_entity *dl_se) 
	if (RB_EMPTY_NODE(&dl_se->rb_node))

		return;



	if (dl_rq->rb_leftmost == &dl_se->rb_node) {

		struct rb_node *next_node;



		next_node = rb_next(&dl_se->rb_node);

		dl_rq->rb_leftmost = next_node;

	}



	rb_erase(&dl_se->rb_node, &dl_rq->rb_root);

	rb_erase_cached(&dl_se->rb_node, &dl_rq->root);

	RB_CLEAR_NODE(&dl_se->rb_node);



	dec_dl_tasks(dl_se, dl_rq);
@@ -1647,7 +1635,7 @@ static void start_hrtick_dl(struct rq *rq, struct task_struct *p) 
static struct sched_dl_entity *pick_next_dl_entity(struct rq *rq,

						   struct dl_rq *dl_rq)

{

	struct rb_node *left = dl_rq->rb_leftmost;

	struct rb_node *left = rb_first_cached(&dl_rq->root);



	if (!left)

		return NULL;
@@ -1771,7 +1759,7 @@ static int pick_dl_task(struct rq *rq, struct task_struct *p, int cpu) 
 */

static struct task_struct *pick_earliest_pushable_dl_task(struct rq *rq, int cpu)

{

	struct rb_node *next_node = rq->dl.pushable_dl_tasks_leftmost;

	struct rb_node *next_node = rq->dl.pushable_dl_tasks_root.rb_leftmost;

	struct task_struct *p = NULL;



	if (!has_pushable_dl_tasks(rq))
@@ -1945,7 +1933,7 @@ static struct task_struct *pick_next_pushable_dl_task(struct rq *rq) 
	if (!has_pushable_dl_tasks(rq))

		return NULL;



	p = rb_entry(rq->dl.pushable_dl_tasks_leftmost,

	p = rb_entry(rq->dl.pushable_dl_tasks_root.rb_leftmost,

		     struct task_struct, pushable_dl_tasks);



	BUG_ON(rq->cpu != task_cpu(p));

kernel/sched/sched.h

+2 −4
Original line number Diff line number Diff line
@@ -549,8 +549,7 @@ struct rt_rq { 
/* Deadline class' related fields in a runqueue */

struct dl_rq {

	/* runqueue is an rbtree, ordered by deadline */

	struct rb_root rb_root;

	struct rb_node *rb_leftmost;

	struct rb_root_cached root;



	unsigned long dl_nr_running;
@@ -574,8 +573,7 @@ struct dl_rq { 
	 * an rb-tree, ordered by tasks' deadlines, with caching

	 * of the leftmost (earliest deadline) element.

	 */

	struct rb_root pushable_dl_tasks_root;

	struct rb_node *pushable_dl_tasks_leftmost;

	struct rb_root_cached pushable_dl_tasks_root;

#else

	struct dl_bw dl_bw;

#endif