[linux-2.6-block.git] / kernel / sched / cpudeadline.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 *  kernel/sched/cpudeadline.c
 *
 *  Global CPU deadline management
 *
 *  Author: Juri Lelli <j.lelli@sssup.it>
 */

static inline int parent(int i)
{
	return (i - 1) >> 1;
}

static inline int left_child(int i)
{
	return (i << 1) + 1;
}

static inline int right_child(int i)
{
	return (i << 1) + 2;
}

static void cpudl_heapify_down(struct cpudl *cp, int idx)
{
	int l, r, largest;

	int orig_cpu = cp->elements[idx].cpu;
	u64 orig_dl = cp->elements[idx].dl;

	if (left_child(idx) >= cp->size)
		return;

	/* adapted from lib/prio_heap.c */
	while (1) {
		u64 largest_dl;

		l = left_child(idx);
		r = right_child(idx);
		largest = idx;
		largest_dl = orig_dl;

		if ((l < cp->size) && dl_time_before(orig_dl,
						cp->elements[l].dl)) {
			largest = l;
			largest_dl = cp->elements[l].dl;
		}
		if ((r < cp->size) && dl_time_before(largest_dl,
						cp->elements[r].dl))
			largest = r;

		if (largest == idx)
			break;

		/* pull largest child onto idx */
		cp->elements[idx].cpu = cp->elements[largest].cpu;
		cp->elements[idx].dl = cp->elements[largest].dl;
		cp->elements[cp->elements[idx].cpu].idx = idx;
		idx = largest;
	}
	/* actual push down of saved original values orig_* */
	cp->elements[idx].cpu = orig_cpu;
	cp->elements[idx].dl = orig_dl;
	cp->elements[cp->elements[idx].cpu].idx = idx;
}

static void cpudl_heapify_up(struct cpudl *cp, int idx)
{
	int p;

	int orig_cpu = cp->elements[idx].cpu;
	u64 orig_dl = cp->elements[idx].dl;

	if (idx == 0)
		return;

	do {
		p = parent(idx);
		if (dl_time_before(orig_dl, cp->elements[p].dl))
			break;
		/* pull parent onto idx */
		cp->elements[idx].cpu = cp->elements[p].cpu;
		cp->elements[idx].dl = cp->elements[p].dl;
		cp->elements[cp->elements[idx].cpu].idx = idx;
		idx = p;
	} while (idx != 0);
	/* actual push up of saved original values orig_* */
	cp->elements[idx].cpu = orig_cpu;
	cp->elements[idx].dl = orig_dl;
	cp->elements[cp->elements[idx].cpu].idx = idx;
}

static void cpudl_heapify(struct cpudl *cp, int idx)
{
	if (idx > 0 && dl_time_before(cp->elements[parent(idx)].dl,
				cp->elements[idx].dl))
		cpudl_heapify_up(cp, idx);
	else
		cpudl_heapify_down(cp, idx);
}

static inline int cpudl_maximum(struct cpudl *cp)
{
	return cp->elements[0].cpu;
}

/*
 * cpudl_find - find the best (later-dl) CPU in the system
 * @cp: the cpudl max-heap context
 * @p: the task
 * @later_mask: a mask to fill in with the selected CPUs (or NULL)
 *
 * Returns: int - CPUs were found
 */
int cpudl_find(struct cpudl *cp, struct task_struct *p,
	       struct cpumask *later_mask)
{
	const struct sched_dl_entity *dl_se = &p->dl;

	if (later_mask &&
	    cpumask_and(later_mask, cp->free_cpus, &p->cpus_mask)) {
		unsigned long cap, max_cap = 0;
		int cpu, max_cpu = -1;

		if (!sched_asym_cpucap_active())
			return 1;

		/* Ensure the capacity of the CPUs fits the task. */
		for_each_cpu(cpu, later_mask) {
			if (!dl_task_fits_capacity(p, cpu)) {
				cpumask_clear_cpu(cpu, later_mask);

				cap = arch_scale_cpu_capacity(cpu);

				if (cap > max_cap ||
				    (cpu == task_cpu(p) && cap == max_cap)) {
					max_cap = cap;
					max_cpu = cpu;
				}
			}
		}

		if (cpumask_empty(later_mask))
			cpumask_set_cpu(max_cpu, later_mask);

		return 1;
	} else {
		int best_cpu = cpudl_maximum(cp);

		WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));

		if (cpumask_test_cpu(best_cpu, &p->cpus_mask) &&
		    dl_time_before(dl_se->deadline, cp->elements[0].dl)) {
			if (later_mask)
				cpumask_set_cpu(best_cpu, later_mask);

			return 1;
		}
	}
	return 0;
}

/*
 * 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
 * @cpu: the target CPU
 * @dl: the new earliest deadline for this CPU
 *
 * Notes: assumes cpu_rq(cpu)->lock is locked
 *
 * Returns: (void)
 */
void cpudl_set(struct cpudl *cp, int cpu, u64 dl)
{
	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 (old_idx == IDX_INVALID) {
		int new_idx = cp->size++;

		cp->elements[new_idx].dl = dl;
		cp->elements[new_idx].cpu = cpu;
		cp->elements[cpu].idx = new_idx;
		cpudl_heapify_up(cp, new_idx);
		cpumask_clear_cpu(cpu, cp->free_cpus);
	} else {
		cp->elements[old_idx].dl = dl;
		cpudl_heapify(cp, old_idx);
	}

	raw_spin_unlock_irqrestore(&cp->lock, flags);
}

/*
 * cpudl_set_freecpu - Set the cpudl.free_cpus
 * @cp: the cpudl max-heap context
 * @cpu: rd attached CPU
 */
void cpudl_set_freecpu(struct cpudl *cp, int cpu)
{
	cpumask_set_cpu(cpu, cp->free_cpus);
}

/*
 * cpudl_clear_freecpu - Clear the cpudl.free_cpus
 * @cp: the cpudl max-heap context
 * @cpu: rd attached CPU
 */
void cpudl_clear_freecpu(struct cpudl *cp, int cpu)
{
	cpumask_clear_cpu(cpu, cp->free_cpus);
}

/*
 * cpudl_init - initialize the cpudl structure
 * @cp: the cpudl max-heap context
 */
int cpudl_init(struct cpudl *cp)
{
	int i;

	raw_spin_lock_init(&cp->lock);
	cp->size = 0;

	cp->elements = kcalloc(nr_cpu_ids,
			       sizeof(struct cpudl_item),
			       GFP_KERNEL);
	if (!cp->elements)
		return -ENOMEM;

	if (!zalloc_cpumask_var(&cp->free_cpus, GFP_KERNEL)) {
		kfree(cp->elements);
		return -ENOMEM;
	}

	for_each_possible_cpu(i)
		cp->elements[i].idx = IDX_INVALID;

	return 0;
}

/*
 * cpudl_cleanup - clean up the cpudl structure
 * @cp: the cpudl max-heap context
 */
void cpudl_cleanup(struct cpudl *cp)
{
	free_cpumask_var(cp->free_cpus);
	kfree(cp->elements);
}
Commit	Line	Data
b886d83c	1	// SPDX-License-Identifier: GPL-2.0-only
6bfd6d72	2	/*
81de6572	3	* kernel/sched/cpudeadline.c
6bfd6d72 JL	4	*
	5	* Global CPU deadline management
	6	*
	7	* Author: Juri Lelli <j.lelli@sssup.it>
6bfd6d72	8	*/
6bfd6d72 JL	9
	10	static inline int parent(int i)
	11	{
	12	return (i - 1) >> 1;
	13	}
	14
	15	static inline int left_child(int i)
	16	{
	17	return (i << 1) + 1;
	18	}
	19
	20	static inline int right_child(int i)
	21	{
	22	return (i << 1) + 2;
	23	}
	24
126b3b68	25	static void cpudl_heapify_down(struct cpudl *cp, int idx)
6bfd6d72 JL	26	{
	27	int l, r, largest;
	28
8e1bc301 TC	29	int orig_cpu = cp->elements[idx].cpu;
	30	u64 orig_dl = cp->elements[idx].dl;
	31
	32	if (left_child(idx) >= cp->size)
	33	return;
	34
6bfd6d72	35	/* adapted from lib/prio_heap.c */
c2e51382	36	while (1) {
8e1bc301	37	u64 largest_dl;
c2e51382	38
6bfd6d72 JL	39	l = left_child(idx);
	40	r = right_child(idx);
	41	largest = idx;
8e1bc301	42	largest_dl = orig_dl;
6bfd6d72	43
8e1bc301 TC	44	if ((l < cp->size) && dl_time_before(orig_dl,
8e1bc301 TC	45	cp->elements[l].dl)) {
6bfd6d72	46	largest = l;
8e1bc301 TC	47	largest_dl = cp->elements[l].dl;
	48	}
	49	if ((r < cp->size) && dl_time_before(largest_dl,
	50	cp->elements[r].dl))
6bfd6d72	51	largest = r;
8e1bc301	52
6bfd6d72 JL	53	if (largest == idx)
	54	break;
	55
8e1bc301 TC	56	/* pull largest child onto idx */
	57	cp->elements[idx].cpu = cp->elements[largest].cpu;
	58	cp->elements[idx].dl = cp->elements[largest].dl;
	59	cp->elements[cp->elements[idx].cpu].idx = idx;
6bfd6d72 JL	60	idx = largest;
6bfd6d72 JL	61	}
8e1bc301 TC	62	/* actual push down of saved original values orig_* */
	63	cp->elements[idx].cpu = orig_cpu;
	64	cp->elements[idx].dl = orig_dl;
	65	cp->elements[cp->elements[idx].cpu].idx = idx;
6bfd6d72 JL	66	}
6bfd6d72 JL	67
126b3b68	68	static void cpudl_heapify_up(struct cpudl *cp, int idx)
6bfd6d72	69	{
8e1bc301 TC	70	int p;
	71
	72	int orig_cpu = cp->elements[idx].cpu;
	73	u64 orig_dl = cp->elements[idx].dl;
	74
	75	if (idx == 0)
	76	return;
	77
	78	do {
	79	p = parent(idx);
	80	if (dl_time_before(orig_dl, cp->elements[p].dl))
	81	break;
	82	/* pull parent onto idx */
	83	cp->elements[idx].cpu = cp->elements[p].cpu;
	84	cp->elements[idx].dl = cp->elements[p].dl;
	85	cp->elements[cp->elements[idx].cpu].idx = idx;
	86	idx = p;
	87	} while (idx != 0);
	88	/* actual push up of saved original values orig_* */
	89	cp->elements[idx].cpu = orig_cpu;
	90	cp->elements[idx].dl = orig_dl;
	91	cp->elements[cp->elements[idx].cpu].idx = idx;
6bfd6d72 JL	92	}
6bfd6d72 JL	93
126b3b68 TC	94	static void cpudl_heapify(struct cpudl *cp, int idx)
	95	{
	96	if (idx > 0 && dl_time_before(cp->elements[parent(idx)].dl,
	97	cp->elements[idx].dl))
	98	cpudl_heapify_up(cp, idx);
	99	else
	100	cpudl_heapify_down(cp, idx);
	101	}
	102
6bfd6d72 JL	103	static inline int cpudl_maximum(struct cpudl *cp)
	104	{
	105	return cp->elements[0].cpu;
	106	}
	107
	108	/*
	109	* cpudl_find - find the best (later-dl) CPU in the system
	110	* @cp: the cpudl max-heap context
	111	* @p: the task
	112	* @later_mask: a mask to fill in with the selected CPUs (or NULL)
	113	*
3261ed0b	114	* Returns: int - CPUs were found
6bfd6d72 JL	115	*/
	116	int cpudl_find(struct cpudl cp, struct task_struct p,
	117	struct cpumask *later_mask)
	118	{
6bfd6d72 JL	119	const struct sched_dl_entity *dl_se = &p->dl;
6bfd6d72 JL	120
16b26943	121	if (later_mask &&
95158a89	122	cpumask_and(later_mask, cp->free_cpus, &p->cpus_mask)) {
23e71d8b LA	123	unsigned long cap, max_cap = 0;
23e71d8b LA	124	int cpu, max_cpu = -1;
b4118988	125
740cf8a7	126	if (!sched_asym_cpucap_active())
b4118988 LA	127	return 1;
	128
	129	/* Ensure the capacity of the CPUs fits the task. */
	130	for_each_cpu(cpu, later_mask) {
23e71d8b	131	if (!dl_task_fits_capacity(p, cpu)) {
b4118988	132	cpumask_clear_cpu(cpu, later_mask);
23e71d8b	133
7bc26384	134	cap = arch_scale_cpu_capacity(cpu);
23e71d8b LA	135
	136	if (cap > max_cap \|\|
	137	(cpu == task_cpu(p) && cap == max_cap)) {
	138	max_cap = cap;
	139	max_cpu = cpu;
	140	}
	141	}
b4118988 LA	142	}
b4118988 LA	143
23e71d8b LA	144	if (cpumask_empty(later_mask))
	145	cpumask_set_cpu(max_cpu, later_mask);
	146
	147	return 1;
3261ed0b BP	148	} else {
3261ed0b BP	149	int best_cpu = cpudl_maximum(cp);
c2e51382	150
3261ed0b	151	WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));
6bfd6d72	152
95158a89	153	if (cpumask_test_cpu(best_cpu, &p->cpus_mask) &&
3261ed0b BP	154	dl_time_before(dl_se->deadline, cp->elements[0].dl)) {
	155	if (later_mask)
	156	cpumask_set_cpu(best_cpu, later_mask);
6bfd6d72	157
3261ed0b BP	158	return 1;
	159	}
	160	}
	161	return 0;
6bfd6d72 JL	162	}
	163
	164	/*
97fb7a0a	165	* cpudl_clear - remove a CPU from the cpudl max-heap
6bfd6d72	166	* @cp: the cpudl max-heap context
97fb7a0a	167	* @cpu: the target CPU
6bfd6d72 JL	168	*
	169	* Notes: assumes cpu_rq(cpu)->lock is locked
	170	*
	171	* Returns: (void)
	172	*/
d8206bb3	173	void cpudl_clear(struct cpudl *cp, int cpu)
6bfd6d72 JL	174	{
	175	int old_idx, new_cpu;
	176	unsigned long flags;
	177
82b95800	178	WARN_ON(!cpu_present(cpu));
6bfd6d72 JL	179
6bfd6d72 JL	180	raw_spin_lock_irqsave(&cp->lock, flags);
d8206bb3	181
944770ab	182	old_idx = cp->elements[cpu].idx;
d8206bb3 TC	183	if (old_idx == IDX_INVALID) {
	184	/*
	185	* Nothing to remove if old_idx was invalid.
	186	* This could happen if a rq_offline_dl is
	187	* called for a CPU without -dl tasks running.
	188	*/
	189	} else {
6bfd6d72 JL	190	new_cpu = cp->elements[cp->size - 1].cpu;
	191	cp->elements[old_idx].dl = cp->elements[cp->size - 1].dl;
	192	cp->elements[old_idx].cpu = new_cpu;
	193	cp->size--;
944770ab PZ	194	cp->elements[new_cpu].idx = old_idx;
944770ab PZ	195	cp->elements[cpu].idx = IDX_INVALID;
126b3b68	196	cpudl_heapify(cp, old_idx);
6bfd6d72	197
d8206bb3	198	cpumask_set_cpu(cpu, cp->free_cpus);
6bfd6d72	199	}
d8206bb3 TC	200	raw_spin_unlock_irqrestore(&cp->lock, flags);
	201	}
	202
	203	/*
	204	* cpudl_set - update the cpudl max-heap
	205	* @cp: the cpudl max-heap context
97fb7a0a IM	206	* @cpu: the target CPU
97fb7a0a IM	207	* @dl: the new earliest deadline for this CPU
d8206bb3 TC	208	*
	209	* Notes: assumes cpu_rq(cpu)->lock is locked
	210	*
	211	* Returns: (void)
	212	*/
	213	void cpudl_set(struct cpudl *cp, int cpu, u64 dl)
	214	{
	215	int old_idx;
	216	unsigned long flags;
	217
	218	WARN_ON(!cpu_present(cpu));
6bfd6d72	219
d8206bb3 TC	220	raw_spin_lock_irqsave(&cp->lock, flags);
	221
	222	old_idx = cp->elements[cpu].idx;
6bfd6d72	223	if (old_idx == IDX_INVALID) {
126b3b68	224	int new_idx = cp->size++;
c2e51382	225
126b3b68 TC	226	cp->elements[new_idx].dl = dl;
	227	cp->elements[new_idx].cpu = cpu;
	228	cp->elements[cpu].idx = new_idx;
	229	cpudl_heapify_up(cp, new_idx);
6bfd6d72 JL	230	cpumask_clear_cpu(cpu, cp->free_cpus);
6bfd6d72 JL	231	} else {
126b3b68 TC	232	cp->elements[old_idx].dl = dl;
126b3b68 TC	233	cpudl_heapify(cp, old_idx);
6bfd6d72 JL	234	}
6bfd6d72 JL	235
6bfd6d72 JL	236	raw_spin_unlock_irqrestore(&cp->lock, flags);
	237	}
	238
16b26943 XP	239	/*
	240	* cpudl_set_freecpu - Set the cpudl.free_cpus
	241	* @cp: the cpudl max-heap context
97fb7a0a	242	* @cpu: rd attached CPU
16b26943 XP	243	*/
	244	void cpudl_set_freecpu(struct cpudl *cp, int cpu)
	245	{
	246	cpumask_set_cpu(cpu, cp->free_cpus);
	247	}
	248
	249	/*
	250	* cpudl_clear_freecpu - Clear the cpudl.free_cpus
	251	* @cp: the cpudl max-heap context
97fb7a0a	252	* @cpu: rd attached CPU
16b26943 XP	253	*/
	254	void cpudl_clear_freecpu(struct cpudl *cp, int cpu)
	255	{
	256	cpumask_clear_cpu(cpu, cp->free_cpus);
	257	}
	258
6bfd6d72 JL	259	/*
	260	* cpudl_init - initialize the cpudl structure
	261	* @cp: the cpudl max-heap context
	262	*/
	263	int cpudl_init(struct cpudl *cp)
	264	{
	265	int i;
	266
6bfd6d72 JL	267	raw_spin_lock_init(&cp->lock);
6bfd6d72 JL	268	cp->size = 0;
944770ab PZ	269
	270	cp->elements = kcalloc(nr_cpu_ids,
	271	sizeof(struct cpudl_item),
	272	GFP_KERNEL);
	273	if (!cp->elements)
	274	return -ENOMEM;
	275
16b26943	276	if (!zalloc_cpumask_var(&cp->free_cpus, GFP_KERNEL)) {
944770ab	277	kfree(cp->elements);
6bfd6d72	278	return -ENOMEM;
944770ab PZ	279	}
	280
	281	for_each_possible_cpu(i)
	282	cp->elements[i].idx = IDX_INVALID;
	283
6bfd6d72 JL	284	return 0;
	285	}
	286
	287	/*
	288	* cpudl_cleanup - clean up the cpudl structure
	289	* @cp: the cpudl max-heap context
	290	*/
	291	void cpudl_cleanup(struct cpudl *cp)
	292	{
6a7cd273	293	free_cpumask_var(cp->free_cpus);
944770ab	294	kfree(cp->elements);
6bfd6d72	295	}