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b886d83c | 1 | // SPDX-License-Identifier: GPL-2.0-only |
6bfd6d72 JL |
2 | /* |
3 | * kernel/sched/cpudl.c | |
4 | * | |
5 | * Global CPU deadline management | |
6 | * | |
7 | * Author: Juri Lelli <j.lelli@sssup.it> | |
6bfd6d72 | 8 | */ |
325ea10c | 9 | #include "sched.h" |
6bfd6d72 JL |
10 | |
11 | static inline int parent(int i) | |
12 | { | |
13 | return (i - 1) >> 1; | |
14 | } | |
15 | ||
16 | static inline int left_child(int i) | |
17 | { | |
18 | return (i << 1) + 1; | |
19 | } | |
20 | ||
21 | static inline int right_child(int i) | |
22 | { | |
23 | return (i << 1) + 2; | |
24 | } | |
25 | ||
126b3b68 | 26 | static void cpudl_heapify_down(struct cpudl *cp, int idx) |
6bfd6d72 JL |
27 | { |
28 | int l, r, largest; | |
29 | ||
8e1bc301 TC |
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 | ||
6bfd6d72 | 36 | /* adapted from lib/prio_heap.c */ |
c2e51382 | 37 | while (1) { |
8e1bc301 | 38 | u64 largest_dl; |
c2e51382 | 39 | |
6bfd6d72 JL |
40 | l = left_child(idx); |
41 | r = right_child(idx); | |
42 | largest = idx; | |
8e1bc301 | 43 | largest_dl = orig_dl; |
6bfd6d72 | 44 | |
8e1bc301 TC |
45 | if ((l < cp->size) && dl_time_before(orig_dl, |
46 | cp->elements[l].dl)) { | |
6bfd6d72 | 47 | largest = l; |
8e1bc301 TC |
48 | largest_dl = cp->elements[l].dl; |
49 | } | |
50 | if ((r < cp->size) && dl_time_before(largest_dl, | |
51 | cp->elements[r].dl)) | |
6bfd6d72 | 52 | largest = r; |
8e1bc301 | 53 | |
6bfd6d72 JL |
54 | if (largest == idx) |
55 | break; | |
56 | ||
8e1bc301 TC |
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; | |
6bfd6d72 JL |
61 | idx = largest; |
62 | } | |
8e1bc301 TC |
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; | |
6bfd6d72 JL |
67 | } |
68 | ||
126b3b68 | 69 | static void cpudl_heapify_up(struct cpudl *cp, int idx) |
6bfd6d72 | 70 | { |
8e1bc301 TC |
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; | |
6bfd6d72 JL |
93 | } |
94 | ||
126b3b68 TC |
95 | static 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 | ||
6bfd6d72 JL |
104 | static 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 | * | |
3261ed0b | 115 | * Returns: int - CPUs were found |
6bfd6d72 JL |
116 | */ |
117 | int cpudl_find(struct cpudl *cp, struct task_struct *p, | |
118 | struct cpumask *later_mask) | |
119 | { | |
6bfd6d72 JL |
120 | const struct sched_dl_entity *dl_se = &p->dl; |
121 | ||
16b26943 | 122 | if (later_mask && |
95158a89 | 123 | cpumask_and(later_mask, cp->free_cpus, &p->cpus_mask)) { |
23e71d8b LA |
124 | unsigned long cap, max_cap = 0; |
125 | int cpu, max_cpu = -1; | |
b4118988 LA |
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) { | |
23e71d8b | 132 | if (!dl_task_fits_capacity(p, cpu)) { |
b4118988 | 133 | cpumask_clear_cpu(cpu, later_mask); |
23e71d8b LA |
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 | } | |
b4118988 LA |
143 | } |
144 | ||
23e71d8b LA |
145 | if (cpumask_empty(later_mask)) |
146 | cpumask_set_cpu(max_cpu, later_mask); | |
147 | ||
148 | return 1; | |
3261ed0b BP |
149 | } else { |
150 | int best_cpu = cpudl_maximum(cp); | |
c2e51382 | 151 | |
3261ed0b | 152 | WARN_ON(best_cpu != -1 && !cpu_present(best_cpu)); |
6bfd6d72 | 153 | |
95158a89 | 154 | if (cpumask_test_cpu(best_cpu, &p->cpus_mask) && |
3261ed0b BP |
155 | dl_time_before(dl_se->deadline, cp->elements[0].dl)) { |
156 | if (later_mask) | |
157 | cpumask_set_cpu(best_cpu, later_mask); | |
6bfd6d72 | 158 | |
3261ed0b BP |
159 | return 1; |
160 | } | |
161 | } | |
162 | return 0; | |
6bfd6d72 JL |
163 | } |
164 | ||
165 | /* | |
97fb7a0a | 166 | * cpudl_clear - remove a CPU from the cpudl max-heap |
6bfd6d72 | 167 | * @cp: the cpudl max-heap context |
97fb7a0a | 168 | * @cpu: the target CPU |
6bfd6d72 JL |
169 | * |
170 | * Notes: assumes cpu_rq(cpu)->lock is locked | |
171 | * | |
172 | * Returns: (void) | |
173 | */ | |
d8206bb3 | 174 | void cpudl_clear(struct cpudl *cp, int cpu) |
6bfd6d72 JL |
175 | { |
176 | int old_idx, new_cpu; | |
177 | unsigned long flags; | |
178 | ||
82b95800 | 179 | WARN_ON(!cpu_present(cpu)); |
6bfd6d72 JL |
180 | |
181 | raw_spin_lock_irqsave(&cp->lock, flags); | |
d8206bb3 | 182 | |
944770ab | 183 | old_idx = cp->elements[cpu].idx; |
d8206bb3 TC |
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 { | |
6bfd6d72 JL |
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--; | |
944770ab PZ |
195 | cp->elements[new_cpu].idx = old_idx; |
196 | cp->elements[cpu].idx = IDX_INVALID; | |
126b3b68 | 197 | cpudl_heapify(cp, old_idx); |
6bfd6d72 | 198 | |
d8206bb3 | 199 | cpumask_set_cpu(cpu, cp->free_cpus); |
6bfd6d72 | 200 | } |
d8206bb3 TC |
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 | |
97fb7a0a IM |
207 | * @cpu: the target CPU |
208 | * @dl: the new earliest deadline for this CPU | |
d8206bb3 TC |
209 | * |
210 | * Notes: assumes cpu_rq(cpu)->lock is locked | |
211 | * | |
212 | * Returns: (void) | |
213 | */ | |
214 | void 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)); | |
6bfd6d72 | 220 | |
d8206bb3 TC |
221 | raw_spin_lock_irqsave(&cp->lock, flags); |
222 | ||
223 | old_idx = cp->elements[cpu].idx; | |
6bfd6d72 | 224 | if (old_idx == IDX_INVALID) { |
126b3b68 | 225 | int new_idx = cp->size++; |
c2e51382 | 226 | |
126b3b68 TC |
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); | |
6bfd6d72 JL |
231 | cpumask_clear_cpu(cpu, cp->free_cpus); |
232 | } else { | |
126b3b68 TC |
233 | cp->elements[old_idx].dl = dl; |
234 | cpudl_heapify(cp, old_idx); | |
6bfd6d72 JL |
235 | } |
236 | ||
6bfd6d72 JL |
237 | raw_spin_unlock_irqrestore(&cp->lock, flags); |
238 | } | |
239 | ||
16b26943 XP |
240 | /* |
241 | * cpudl_set_freecpu - Set the cpudl.free_cpus | |
242 | * @cp: the cpudl max-heap context | |
97fb7a0a | 243 | * @cpu: rd attached CPU |
16b26943 XP |
244 | */ |
245 | void 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 | |
97fb7a0a | 253 | * @cpu: rd attached CPU |
16b26943 XP |
254 | */ |
255 | void cpudl_clear_freecpu(struct cpudl *cp, int cpu) | |
256 | { | |
257 | cpumask_clear_cpu(cpu, cp->free_cpus); | |
258 | } | |
259 | ||
6bfd6d72 JL |
260 | /* |
261 | * cpudl_init - initialize the cpudl structure | |
262 | * @cp: the cpudl max-heap context | |
263 | */ | |
264 | int cpudl_init(struct cpudl *cp) | |
265 | { | |
266 | int i; | |
267 | ||
6bfd6d72 JL |
268 | raw_spin_lock_init(&cp->lock); |
269 | cp->size = 0; | |
944770ab PZ |
270 | |
271 | cp->elements = kcalloc(nr_cpu_ids, | |
272 | sizeof(struct cpudl_item), | |
273 | GFP_KERNEL); | |
274 | if (!cp->elements) | |
275 | return -ENOMEM; | |
276 | ||
16b26943 | 277 | if (!zalloc_cpumask_var(&cp->free_cpus, GFP_KERNEL)) { |
944770ab | 278 | kfree(cp->elements); |
6bfd6d72 | 279 | return -ENOMEM; |
944770ab PZ |
280 | } |
281 | ||
282 | for_each_possible_cpu(i) | |
283 | cp->elements[i].idx = IDX_INVALID; | |
284 | ||
6bfd6d72 JL |
285 | return 0; |
286 | } | |
287 | ||
288 | /* | |
289 | * cpudl_cleanup - clean up the cpudl structure | |
290 | * @cp: the cpudl max-heap context | |
291 | */ | |
292 | void cpudl_cleanup(struct cpudl *cp) | |
293 | { | |
6a7cd273 | 294 | free_cpumask_var(cp->free_cpus); |
944770ab | 295 | kfree(cp->elements); |
6bfd6d72 | 296 | } |