Commit | Line | Data |
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6bfd6d72 JL |
1 | /* |
2 | * kernel/sched/cpudl.c | |
3 | * | |
4 | * Global CPU deadline management | |
5 | * | |
6 | * Author: Juri Lelli <j.lelli@sssup.it> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU General Public License | |
10 | * as published by the Free Software Foundation; version 2 | |
11 | * of the License. | |
12 | */ | |
325ea10c | 13 | #include "sched.h" |
6bfd6d72 JL |
14 | |
15 | static inline int parent(int i) | |
16 | { | |
17 | return (i - 1) >> 1; | |
18 | } | |
19 | ||
20 | static inline int left_child(int i) | |
21 | { | |
22 | return (i << 1) + 1; | |
23 | } | |
24 | ||
25 | static inline int right_child(int i) | |
26 | { | |
27 | return (i << 1) + 2; | |
28 | } | |
29 | ||
126b3b68 | 30 | static void cpudl_heapify_down(struct cpudl *cp, int idx) |
6bfd6d72 JL |
31 | { |
32 | int l, r, largest; | |
33 | ||
8e1bc301 TC |
34 | int orig_cpu = cp->elements[idx].cpu; |
35 | u64 orig_dl = cp->elements[idx].dl; | |
36 | ||
37 | if (left_child(idx) >= cp->size) | |
38 | return; | |
39 | ||
6bfd6d72 | 40 | /* adapted from lib/prio_heap.c */ |
c2e51382 | 41 | while (1) { |
8e1bc301 | 42 | u64 largest_dl; |
c2e51382 | 43 | |
6bfd6d72 JL |
44 | l = left_child(idx); |
45 | r = right_child(idx); | |
46 | largest = idx; | |
8e1bc301 | 47 | largest_dl = orig_dl; |
6bfd6d72 | 48 | |
8e1bc301 TC |
49 | if ((l < cp->size) && dl_time_before(orig_dl, |
50 | cp->elements[l].dl)) { | |
6bfd6d72 | 51 | largest = l; |
8e1bc301 TC |
52 | largest_dl = cp->elements[l].dl; |
53 | } | |
54 | if ((r < cp->size) && dl_time_before(largest_dl, | |
55 | cp->elements[r].dl)) | |
6bfd6d72 | 56 | largest = r; |
8e1bc301 | 57 | |
6bfd6d72 JL |
58 | if (largest == idx) |
59 | break; | |
60 | ||
8e1bc301 TC |
61 | /* pull largest child onto idx */ |
62 | cp->elements[idx].cpu = cp->elements[largest].cpu; | |
63 | cp->elements[idx].dl = cp->elements[largest].dl; | |
64 | cp->elements[cp->elements[idx].cpu].idx = idx; | |
6bfd6d72 JL |
65 | idx = largest; |
66 | } | |
8e1bc301 TC |
67 | /* actual push down of saved original values orig_* */ |
68 | cp->elements[idx].cpu = orig_cpu; | |
69 | cp->elements[idx].dl = orig_dl; | |
70 | cp->elements[cp->elements[idx].cpu].idx = idx; | |
6bfd6d72 JL |
71 | } |
72 | ||
126b3b68 | 73 | static void cpudl_heapify_up(struct cpudl *cp, int idx) |
6bfd6d72 | 74 | { |
8e1bc301 TC |
75 | int p; |
76 | ||
77 | int orig_cpu = cp->elements[idx].cpu; | |
78 | u64 orig_dl = cp->elements[idx].dl; | |
79 | ||
80 | if (idx == 0) | |
81 | return; | |
82 | ||
83 | do { | |
84 | p = parent(idx); | |
85 | if (dl_time_before(orig_dl, cp->elements[p].dl)) | |
86 | break; | |
87 | /* pull parent onto idx */ | |
88 | cp->elements[idx].cpu = cp->elements[p].cpu; | |
89 | cp->elements[idx].dl = cp->elements[p].dl; | |
90 | cp->elements[cp->elements[idx].cpu].idx = idx; | |
91 | idx = p; | |
92 | } while (idx != 0); | |
93 | /* actual push up of saved original values orig_* */ | |
94 | cp->elements[idx].cpu = orig_cpu; | |
95 | cp->elements[idx].dl = orig_dl; | |
96 | cp->elements[cp->elements[idx].cpu].idx = idx; | |
6bfd6d72 JL |
97 | } |
98 | ||
126b3b68 TC |
99 | static void cpudl_heapify(struct cpudl *cp, int idx) |
100 | { | |
101 | if (idx > 0 && dl_time_before(cp->elements[parent(idx)].dl, | |
102 | cp->elements[idx].dl)) | |
103 | cpudl_heapify_up(cp, idx); | |
104 | else | |
105 | cpudl_heapify_down(cp, idx); | |
106 | } | |
107 | ||
6bfd6d72 JL |
108 | static inline int cpudl_maximum(struct cpudl *cp) |
109 | { | |
110 | return cp->elements[0].cpu; | |
111 | } | |
112 | ||
113 | /* | |
114 | * cpudl_find - find the best (later-dl) CPU in the system | |
115 | * @cp: the cpudl max-heap context | |
116 | * @p: the task | |
117 | * @later_mask: a mask to fill in with the selected CPUs (or NULL) | |
118 | * | |
3261ed0b | 119 | * Returns: int - CPUs were found |
6bfd6d72 JL |
120 | */ |
121 | int cpudl_find(struct cpudl *cp, struct task_struct *p, | |
122 | struct cpumask *later_mask) | |
123 | { | |
6bfd6d72 JL |
124 | const struct sched_dl_entity *dl_se = &p->dl; |
125 | ||
16b26943 | 126 | if (later_mask && |
0c98d344 | 127 | cpumask_and(later_mask, cp->free_cpus, &p->cpus_allowed)) { |
3261ed0b BP |
128 | return 1; |
129 | } else { | |
130 | int best_cpu = cpudl_maximum(cp); | |
c2e51382 | 131 | |
3261ed0b | 132 | WARN_ON(best_cpu != -1 && !cpu_present(best_cpu)); |
6bfd6d72 | 133 | |
3261ed0b BP |
134 | if (cpumask_test_cpu(best_cpu, &p->cpus_allowed) && |
135 | dl_time_before(dl_se->deadline, cp->elements[0].dl)) { | |
136 | if (later_mask) | |
137 | cpumask_set_cpu(best_cpu, later_mask); | |
6bfd6d72 | 138 | |
3261ed0b BP |
139 | return 1; |
140 | } | |
141 | } | |
142 | return 0; | |
6bfd6d72 JL |
143 | } |
144 | ||
145 | /* | |
97fb7a0a | 146 | * cpudl_clear - remove a CPU from the cpudl max-heap |
6bfd6d72 | 147 | * @cp: the cpudl max-heap context |
97fb7a0a | 148 | * @cpu: the target CPU |
6bfd6d72 JL |
149 | * |
150 | * Notes: assumes cpu_rq(cpu)->lock is locked | |
151 | * | |
152 | * Returns: (void) | |
153 | */ | |
d8206bb3 | 154 | void cpudl_clear(struct cpudl *cp, int cpu) |
6bfd6d72 JL |
155 | { |
156 | int old_idx, new_cpu; | |
157 | unsigned long flags; | |
158 | ||
82b95800 | 159 | WARN_ON(!cpu_present(cpu)); |
6bfd6d72 JL |
160 | |
161 | raw_spin_lock_irqsave(&cp->lock, flags); | |
d8206bb3 | 162 | |
944770ab | 163 | old_idx = cp->elements[cpu].idx; |
d8206bb3 TC |
164 | if (old_idx == IDX_INVALID) { |
165 | /* | |
166 | * Nothing to remove if old_idx was invalid. | |
167 | * This could happen if a rq_offline_dl is | |
168 | * called for a CPU without -dl tasks running. | |
169 | */ | |
170 | } else { | |
6bfd6d72 JL |
171 | new_cpu = cp->elements[cp->size - 1].cpu; |
172 | cp->elements[old_idx].dl = cp->elements[cp->size - 1].dl; | |
173 | cp->elements[old_idx].cpu = new_cpu; | |
174 | cp->size--; | |
944770ab PZ |
175 | cp->elements[new_cpu].idx = old_idx; |
176 | cp->elements[cpu].idx = IDX_INVALID; | |
126b3b68 | 177 | cpudl_heapify(cp, old_idx); |
6bfd6d72 | 178 | |
d8206bb3 | 179 | cpumask_set_cpu(cpu, cp->free_cpus); |
6bfd6d72 | 180 | } |
d8206bb3 TC |
181 | raw_spin_unlock_irqrestore(&cp->lock, flags); |
182 | } | |
183 | ||
184 | /* | |
185 | * cpudl_set - update the cpudl max-heap | |
186 | * @cp: the cpudl max-heap context | |
97fb7a0a IM |
187 | * @cpu: the target CPU |
188 | * @dl: the new earliest deadline for this CPU | |
d8206bb3 TC |
189 | * |
190 | * Notes: assumes cpu_rq(cpu)->lock is locked | |
191 | * | |
192 | * Returns: (void) | |
193 | */ | |
194 | void cpudl_set(struct cpudl *cp, int cpu, u64 dl) | |
195 | { | |
196 | int old_idx; | |
197 | unsigned long flags; | |
198 | ||
199 | WARN_ON(!cpu_present(cpu)); | |
6bfd6d72 | 200 | |
d8206bb3 TC |
201 | raw_spin_lock_irqsave(&cp->lock, flags); |
202 | ||
203 | old_idx = cp->elements[cpu].idx; | |
6bfd6d72 | 204 | if (old_idx == IDX_INVALID) { |
126b3b68 | 205 | int new_idx = cp->size++; |
c2e51382 | 206 | |
126b3b68 TC |
207 | cp->elements[new_idx].dl = dl; |
208 | cp->elements[new_idx].cpu = cpu; | |
209 | cp->elements[cpu].idx = new_idx; | |
210 | cpudl_heapify_up(cp, new_idx); | |
6bfd6d72 JL |
211 | cpumask_clear_cpu(cpu, cp->free_cpus); |
212 | } else { | |
126b3b68 TC |
213 | cp->elements[old_idx].dl = dl; |
214 | cpudl_heapify(cp, old_idx); | |
6bfd6d72 JL |
215 | } |
216 | ||
6bfd6d72 JL |
217 | raw_spin_unlock_irqrestore(&cp->lock, flags); |
218 | } | |
219 | ||
16b26943 XP |
220 | /* |
221 | * cpudl_set_freecpu - Set the cpudl.free_cpus | |
222 | * @cp: the cpudl max-heap context | |
97fb7a0a | 223 | * @cpu: rd attached CPU |
16b26943 XP |
224 | */ |
225 | void cpudl_set_freecpu(struct cpudl *cp, int cpu) | |
226 | { | |
227 | cpumask_set_cpu(cpu, cp->free_cpus); | |
228 | } | |
229 | ||
230 | /* | |
231 | * cpudl_clear_freecpu - Clear the cpudl.free_cpus | |
232 | * @cp: the cpudl max-heap context | |
97fb7a0a | 233 | * @cpu: rd attached CPU |
16b26943 XP |
234 | */ |
235 | void cpudl_clear_freecpu(struct cpudl *cp, int cpu) | |
236 | { | |
237 | cpumask_clear_cpu(cpu, cp->free_cpus); | |
238 | } | |
239 | ||
6bfd6d72 JL |
240 | /* |
241 | * cpudl_init - initialize the cpudl structure | |
242 | * @cp: the cpudl max-heap context | |
243 | */ | |
244 | int cpudl_init(struct cpudl *cp) | |
245 | { | |
246 | int i; | |
247 | ||
6bfd6d72 JL |
248 | raw_spin_lock_init(&cp->lock); |
249 | cp->size = 0; | |
944770ab PZ |
250 | |
251 | cp->elements = kcalloc(nr_cpu_ids, | |
252 | sizeof(struct cpudl_item), | |
253 | GFP_KERNEL); | |
254 | if (!cp->elements) | |
255 | return -ENOMEM; | |
256 | ||
16b26943 | 257 | if (!zalloc_cpumask_var(&cp->free_cpus, GFP_KERNEL)) { |
944770ab | 258 | kfree(cp->elements); |
6bfd6d72 | 259 | return -ENOMEM; |
944770ab PZ |
260 | } |
261 | ||
262 | for_each_possible_cpu(i) | |
263 | cp->elements[i].idx = IDX_INVALID; | |
264 | ||
6bfd6d72 JL |
265 | return 0; |
266 | } | |
267 | ||
268 | /* | |
269 | * cpudl_cleanup - clean up the cpudl structure | |
270 | * @cp: the cpudl max-heap context | |
271 | */ | |
272 | void cpudl_cleanup(struct cpudl *cp) | |
273 | { | |
6a7cd273 | 274 | free_cpumask_var(cp->free_cpus); |
944770ab | 275 | kfree(cp->elements); |
6bfd6d72 | 276 | } |