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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * kernel/sched/cpudeadline.c
4 *
5 * Global CPU deadline management
6 *
7 * Author: Juri Lelli <j.lelli@sssup.it>
8 */
9
10static inline int parent(int i)
11{
12 return (i - 1) >> 1;
13}
14
15static inline int left_child(int i)
16{
17 return (i << 1) + 1;
18}
19
20static inline int right_child(int i)
21{
22 return (i << 1) + 2;
23}
24
25static void cpudl_heapify_down(struct cpudl *cp, int idx)
26{
27 int l, r, largest;
28
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
35 /* adapted from lib/prio_heap.c */
36 while (1) {
37 u64 largest_dl;
38
39 l = left_child(idx);
40 r = right_child(idx);
41 largest = idx;
42 largest_dl = orig_dl;
43
44 if ((l < cp->size) && dl_time_before(orig_dl,
45 cp->elements[l].dl)) {
46 largest = l;
47 largest_dl = cp->elements[l].dl;
48 }
49 if ((r < cp->size) && dl_time_before(largest_dl,
50 cp->elements[r].dl))
51 largest = r;
52
53 if (largest == idx)
54 break;
55
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;
60 idx = largest;
61 }
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;
66}
67
68static void cpudl_heapify_up(struct cpudl *cp, int idx)
69{
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;
92}
93
94static 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
103static 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 *
114 * Returns: int - CPUs were found
115 */
116int cpudl_find(struct cpudl *cp, struct task_struct *p,
117 struct cpumask *later_mask)
118{
119 const struct sched_dl_entity *dl_se = &p->dl;
120
121 if (later_mask &&
122 cpumask_and(later_mask, cp->free_cpus, &p->cpus_mask)) {
123 unsigned long cap, max_cap = 0;
124 int cpu, max_cpu = -1;
125
126 if (!sched_asym_cpucap_active())
127 return 1;
128
129 /* Ensure the capacity of the CPUs fits the task. */
130 for_each_cpu(cpu, later_mask) {
131 if (!dl_task_fits_capacity(p, cpu)) {
132 cpumask_clear_cpu(cpu, later_mask);
133
134 cap = capacity_orig_of(cpu);
135
136 if (cap > max_cap ||
137 (cpu == task_cpu(p) && cap == max_cap)) {
138 max_cap = cap;
139 max_cpu = cpu;
140 }
141 }
142 }
143
144 if (cpumask_empty(later_mask))
145 cpumask_set_cpu(max_cpu, later_mask);
146
147 return 1;
148 } else {
149 int best_cpu = cpudl_maximum(cp);
150
151 WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));
152
153 if (cpumask_test_cpu(best_cpu, &p->cpus_mask) &&
154 dl_time_before(dl_se->deadline, cp->elements[0].dl)) {
155 if (later_mask)
156 cpumask_set_cpu(best_cpu, later_mask);
157
158 return 1;
159 }
160 }
161 return 0;
162}
163
164/*
165 * cpudl_clear - remove a CPU from the cpudl max-heap
166 * @cp: the cpudl max-heap context
167 * @cpu: the target CPU
168 *
169 * Notes: assumes cpu_rq(cpu)->lock is locked
170 *
171 * Returns: (void)
172 */
173void cpudl_clear(struct cpudl *cp, int cpu)
174{
175 int old_idx, new_cpu;
176 unsigned long flags;
177
178 WARN_ON(!cpu_present(cpu));
179
180 raw_spin_lock_irqsave(&cp->lock, flags);
181
182 old_idx = cp->elements[cpu].idx;
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 {
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--;
194 cp->elements[new_cpu].idx = old_idx;
195 cp->elements[cpu].idx = IDX_INVALID;
196 cpudl_heapify(cp, old_idx);
197
198 cpumask_set_cpu(cpu, cp->free_cpus);
199 }
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
206 * @cpu: the target CPU
207 * @dl: the new earliest deadline for this CPU
208 *
209 * Notes: assumes cpu_rq(cpu)->lock is locked
210 *
211 * Returns: (void)
212 */
213void 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));
219
220 raw_spin_lock_irqsave(&cp->lock, flags);
221
222 old_idx = cp->elements[cpu].idx;
223 if (old_idx == IDX_INVALID) {
224 int new_idx = cp->size++;
225
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);
230 cpumask_clear_cpu(cpu, cp->free_cpus);
231 } else {
232 cp->elements[old_idx].dl = dl;
233 cpudl_heapify(cp, old_idx);
234 }
235
236 raw_spin_unlock_irqrestore(&cp->lock, flags);
237}
238
239/*
240 * cpudl_set_freecpu - Set the cpudl.free_cpus
241 * @cp: the cpudl max-heap context
242 * @cpu: rd attached CPU
243 */
244void 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
252 * @cpu: rd attached CPU
253 */
254void cpudl_clear_freecpu(struct cpudl *cp, int cpu)
255{
256 cpumask_clear_cpu(cpu, cp->free_cpus);
257}
258
259/*
260 * cpudl_init - initialize the cpudl structure
261 * @cp: the cpudl max-heap context
262 */
263int cpudl_init(struct cpudl *cp)
264{
265 int i;
266
267 raw_spin_lock_init(&cp->lock);
268 cp->size = 0;
269
270 cp->elements = kcalloc(nr_cpu_ids,
271 sizeof(struct cpudl_item),
272 GFP_KERNEL);
273 if (!cp->elements)
274 return -ENOMEM;
275
276 if (!zalloc_cpumask_var(&cp->free_cpus, GFP_KERNEL)) {
277 kfree(cp->elements);
278 return -ENOMEM;
279 }
280
281 for_each_possible_cpu(i)
282 cp->elements[i].idx = IDX_INVALID;
283
284 return 0;
285}
286
287/*
288 * cpudl_cleanup - clean up the cpudl structure
289 * @cp: the cpudl max-heap context
290 */
291void cpudl_cleanup(struct cpudl *cp)
292{
293 free_cpumask_var(cp->free_cpus);
294 kfree(cp->elements);
295}
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * kernel/sched/cpudl.c
4 *
5 * Global CPU deadline management
6 *
7 * Author: Juri Lelli <j.lelli@sssup.it>
8 */
9#include "sched.h"
10
11static inline int parent(int i)
12{
13 return (i - 1) >> 1;
14}
15
16static inline int left_child(int i)
17{
18 return (i << 1) + 1;
19}
20
21static inline int right_child(int i)
22{
23 return (i << 1) + 2;
24}
25
26static void cpudl_heapify_down(struct cpudl *cp, int idx)
27{
28 int l, r, largest;
29
30 int orig_cpu = cp->elements[idx].cpu;
31 u64 orig_dl = cp->elements[idx].dl;
32
33 if (left_child(idx) >= cp->size)
34 return;
35
36 /* adapted from lib/prio_heap.c */
37 while (1) {
38 u64 largest_dl;
39
40 l = left_child(idx);
41 r = right_child(idx);
42 largest = idx;
43 largest_dl = orig_dl;
44
45 if ((l < cp->size) && dl_time_before(orig_dl,
46 cp->elements[l].dl)) {
47 largest = l;
48 largest_dl = cp->elements[l].dl;
49 }
50 if ((r < cp->size) && dl_time_before(largest_dl,
51 cp->elements[r].dl))
52 largest = r;
53
54 if (largest == idx)
55 break;
56
57 /* pull largest child onto idx */
58 cp->elements[idx].cpu = cp->elements[largest].cpu;
59 cp->elements[idx].dl = cp->elements[largest].dl;
60 cp->elements[cp->elements[idx].cpu].idx = idx;
61 idx = largest;
62 }
63 /* actual push down of saved original values orig_* */
64 cp->elements[idx].cpu = orig_cpu;
65 cp->elements[idx].dl = orig_dl;
66 cp->elements[cp->elements[idx].cpu].idx = idx;
67}
68
69static void cpudl_heapify_up(struct cpudl *cp, int idx)
70{
71 int p;
72
73 int orig_cpu = cp->elements[idx].cpu;
74 u64 orig_dl = cp->elements[idx].dl;
75
76 if (idx == 0)
77 return;
78
79 do {
80 p = parent(idx);
81 if (dl_time_before(orig_dl, cp->elements[p].dl))
82 break;
83 /* pull parent onto idx */
84 cp->elements[idx].cpu = cp->elements[p].cpu;
85 cp->elements[idx].dl = cp->elements[p].dl;
86 cp->elements[cp->elements[idx].cpu].idx = idx;
87 idx = p;
88 } while (idx != 0);
89 /* actual push up of saved original values orig_* */
90 cp->elements[idx].cpu = orig_cpu;
91 cp->elements[idx].dl = orig_dl;
92 cp->elements[cp->elements[idx].cpu].idx = idx;
93}
94
95static void cpudl_heapify(struct cpudl *cp, int idx)
96{
97 if (idx > 0 && dl_time_before(cp->elements[parent(idx)].dl,
98 cp->elements[idx].dl))
99 cpudl_heapify_up(cp, idx);
100 else
101 cpudl_heapify_down(cp, idx);
102}
103
104static inline int cpudl_maximum(struct cpudl *cp)
105{
106 return cp->elements[0].cpu;
107}
108
109/*
110 * cpudl_find - find the best (later-dl) CPU in the system
111 * @cp: the cpudl max-heap context
112 * @p: the task
113 * @later_mask: a mask to fill in with the selected CPUs (or NULL)
114 *
115 * Returns: int - CPUs were found
116 */
117int cpudl_find(struct cpudl *cp, struct task_struct *p,
118 struct cpumask *later_mask)
119{
120 const struct sched_dl_entity *dl_se = &p->dl;
121
122 if (later_mask &&
123 cpumask_and(later_mask, cp->free_cpus, &p->cpus_mask)) {
124 unsigned long cap, max_cap = 0;
125 int cpu, max_cpu = -1;
126
127 if (!static_branch_unlikely(&sched_asym_cpucapacity))
128 return 1;
129
130 /* Ensure the capacity of the CPUs fits the task. */
131 for_each_cpu(cpu, later_mask) {
132 if (!dl_task_fits_capacity(p, cpu)) {
133 cpumask_clear_cpu(cpu, later_mask);
134
135 cap = capacity_orig_of(cpu);
136
137 if (cap > max_cap ||
138 (cpu == task_cpu(p) && cap == max_cap)) {
139 max_cap = cap;
140 max_cpu = cpu;
141 }
142 }
143 }
144
145 if (cpumask_empty(later_mask))
146 cpumask_set_cpu(max_cpu, later_mask);
147
148 return 1;
149 } else {
150 int best_cpu = cpudl_maximum(cp);
151
152 WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));
153
154 if (cpumask_test_cpu(best_cpu, &p->cpus_mask) &&
155 dl_time_before(dl_se->deadline, cp->elements[0].dl)) {
156 if (later_mask)
157 cpumask_set_cpu(best_cpu, later_mask);
158
159 return 1;
160 }
161 }
162 return 0;
163}
164
165/*
166 * cpudl_clear - remove a CPU from the cpudl max-heap
167 * @cp: the cpudl max-heap context
168 * @cpu: the target CPU
169 *
170 * Notes: assumes cpu_rq(cpu)->lock is locked
171 *
172 * Returns: (void)
173 */
174void cpudl_clear(struct cpudl *cp, int cpu)
175{
176 int old_idx, new_cpu;
177 unsigned long flags;
178
179 WARN_ON(!cpu_present(cpu));
180
181 raw_spin_lock_irqsave(&cp->lock, flags);
182
183 old_idx = cp->elements[cpu].idx;
184 if (old_idx == IDX_INVALID) {
185 /*
186 * Nothing to remove if old_idx was invalid.
187 * This could happen if a rq_offline_dl is
188 * called for a CPU without -dl tasks running.
189 */
190 } else {
191 new_cpu = cp->elements[cp->size - 1].cpu;
192 cp->elements[old_idx].dl = cp->elements[cp->size - 1].dl;
193 cp->elements[old_idx].cpu = new_cpu;
194 cp->size--;
195 cp->elements[new_cpu].idx = old_idx;
196 cp->elements[cpu].idx = IDX_INVALID;
197 cpudl_heapify(cp, old_idx);
198
199 cpumask_set_cpu(cpu, cp->free_cpus);
200 }
201 raw_spin_unlock_irqrestore(&cp->lock, flags);
202}
203
204/*
205 * cpudl_set - update the cpudl max-heap
206 * @cp: the cpudl max-heap context
207 * @cpu: the target CPU
208 * @dl: the new earliest deadline for this CPU
209 *
210 * Notes: assumes cpu_rq(cpu)->lock is locked
211 *
212 * Returns: (void)
213 */
214void cpudl_set(struct cpudl *cp, int cpu, u64 dl)
215{
216 int old_idx;
217 unsigned long flags;
218
219 WARN_ON(!cpu_present(cpu));
220
221 raw_spin_lock_irqsave(&cp->lock, flags);
222
223 old_idx = cp->elements[cpu].idx;
224 if (old_idx == IDX_INVALID) {
225 int new_idx = cp->size++;
226
227 cp->elements[new_idx].dl = dl;
228 cp->elements[new_idx].cpu = cpu;
229 cp->elements[cpu].idx = new_idx;
230 cpudl_heapify_up(cp, new_idx);
231 cpumask_clear_cpu(cpu, cp->free_cpus);
232 } else {
233 cp->elements[old_idx].dl = dl;
234 cpudl_heapify(cp, old_idx);
235 }
236
237 raw_spin_unlock_irqrestore(&cp->lock, flags);
238}
239
240/*
241 * cpudl_set_freecpu - Set the cpudl.free_cpus
242 * @cp: the cpudl max-heap context
243 * @cpu: rd attached CPU
244 */
245void cpudl_set_freecpu(struct cpudl *cp, int cpu)
246{
247 cpumask_set_cpu(cpu, cp->free_cpus);
248}
249
250/*
251 * cpudl_clear_freecpu - Clear the cpudl.free_cpus
252 * @cp: the cpudl max-heap context
253 * @cpu: rd attached CPU
254 */
255void cpudl_clear_freecpu(struct cpudl *cp, int cpu)
256{
257 cpumask_clear_cpu(cpu, cp->free_cpus);
258}
259
260/*
261 * cpudl_init - initialize the cpudl structure
262 * @cp: the cpudl max-heap context
263 */
264int cpudl_init(struct cpudl *cp)
265{
266 int i;
267
268 raw_spin_lock_init(&cp->lock);
269 cp->size = 0;
270
271 cp->elements = kcalloc(nr_cpu_ids,
272 sizeof(struct cpudl_item),
273 GFP_KERNEL);
274 if (!cp->elements)
275 return -ENOMEM;
276
277 if (!zalloc_cpumask_var(&cp->free_cpus, GFP_KERNEL)) {
278 kfree(cp->elements);
279 return -ENOMEM;
280 }
281
282 for_each_possible_cpu(i)
283 cp->elements[i].idx = IDX_INVALID;
284
285 return 0;
286}
287
288/*
289 * cpudl_cleanup - clean up the cpudl structure
290 * @cp: the cpudl max-heap context
291 */
292void cpudl_cleanup(struct cpudl *cp)
293{
294 free_cpumask_var(cp->free_cpus);
295 kfree(cp->elements);
296}