1 // SPDX-License-Identifier: GPL-2.0-only
5 * Global CPU deadline management
7 * Author: Juri Lelli <j.lelli@sssup.it>
11 static inline int parent(int i)
16 static inline int left_child(int i)
21 static inline int right_child(int i)
26 static void cpudl_heapify_down(struct cpudl *cp, int idx)
30 int orig_cpu = cp->elements[idx].cpu;
31 u64 orig_dl = cp->elements[idx].dl;
33 if (left_child(idx) >= cp->size)
36 /* adapted from lib/prio_heap.c */
45 if ((l < cp->size) && dl_time_before(orig_dl,
46 cp->elements[l].dl)) {
48 largest_dl = cp->elements[l].dl;
50 if ((r < cp->size) && dl_time_before(largest_dl,
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;
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;
69 static void cpudl_heapify_up(struct cpudl *cp, int idx)
73 int orig_cpu = cp->elements[idx].cpu;
74 u64 orig_dl = cp->elements[idx].dl;
81 if (dl_time_before(orig_dl, cp->elements[p].dl))
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;
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;
95 static void cpudl_heapify(struct cpudl *cp, int idx)
97 if (idx > 0 && dl_time_before(cp->elements[parent(idx)].dl,
98 cp->elements[idx].dl))
99 cpudl_heapify_up(cp, idx);
101 cpudl_heapify_down(cp, idx);
104 static inline int cpudl_maximum(struct cpudl *cp)
106 return cp->elements[0].cpu;
110 * cpudl_find - find the best (later-dl) CPU in the system
111 * @cp: the cpudl max-heap context
113 * @later_mask: a mask to fill in with the selected CPUs (or NULL)
115 * Returns: int - CPUs were found
117 int cpudl_find(struct cpudl *cp, struct task_struct *p,
118 struct cpumask *later_mask)
120 const struct sched_dl_entity *dl_se = &p->dl;
123 cpumask_and(later_mask, cp->free_cpus, &p->cpus_allowed)) {
126 int best_cpu = cpudl_maximum(cp);
128 WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));
130 if (cpumask_test_cpu(best_cpu, &p->cpus_allowed) &&
131 dl_time_before(dl_se->deadline, cp->elements[0].dl)) {
133 cpumask_set_cpu(best_cpu, later_mask);
142 * cpudl_clear - remove a CPU from the cpudl max-heap
143 * @cp: the cpudl max-heap context
144 * @cpu: the target CPU
146 * Notes: assumes cpu_rq(cpu)->lock is locked
150 void cpudl_clear(struct cpudl *cp, int cpu)
152 int old_idx, new_cpu;
155 WARN_ON(!cpu_present(cpu));
157 raw_spin_lock_irqsave(&cp->lock, flags);
159 old_idx = cp->elements[cpu].idx;
160 if (old_idx == IDX_INVALID) {
162 * Nothing to remove if old_idx was invalid.
163 * This could happen if a rq_offline_dl is
164 * called for a CPU without -dl tasks running.
167 new_cpu = cp->elements[cp->size - 1].cpu;
168 cp->elements[old_idx].dl = cp->elements[cp->size - 1].dl;
169 cp->elements[old_idx].cpu = new_cpu;
171 cp->elements[new_cpu].idx = old_idx;
172 cp->elements[cpu].idx = IDX_INVALID;
173 cpudl_heapify(cp, old_idx);
175 cpumask_set_cpu(cpu, cp->free_cpus);
177 raw_spin_unlock_irqrestore(&cp->lock, flags);
181 * cpudl_set - update the cpudl max-heap
182 * @cp: the cpudl max-heap context
183 * @cpu: the target CPU
184 * @dl: the new earliest deadline for this CPU
186 * Notes: assumes cpu_rq(cpu)->lock is locked
190 void cpudl_set(struct cpudl *cp, int cpu, u64 dl)
195 WARN_ON(!cpu_present(cpu));
197 raw_spin_lock_irqsave(&cp->lock, flags);
199 old_idx = cp->elements[cpu].idx;
200 if (old_idx == IDX_INVALID) {
201 int new_idx = cp->size++;
203 cp->elements[new_idx].dl = dl;
204 cp->elements[new_idx].cpu = cpu;
205 cp->elements[cpu].idx = new_idx;
206 cpudl_heapify_up(cp, new_idx);
207 cpumask_clear_cpu(cpu, cp->free_cpus);
209 cp->elements[old_idx].dl = dl;
210 cpudl_heapify(cp, old_idx);
213 raw_spin_unlock_irqrestore(&cp->lock, flags);
217 * cpudl_set_freecpu - Set the cpudl.free_cpus
218 * @cp: the cpudl max-heap context
219 * @cpu: rd attached CPU
221 void cpudl_set_freecpu(struct cpudl *cp, int cpu)
223 cpumask_set_cpu(cpu, cp->free_cpus);
227 * cpudl_clear_freecpu - Clear the cpudl.free_cpus
228 * @cp: the cpudl max-heap context
229 * @cpu: rd attached CPU
231 void cpudl_clear_freecpu(struct cpudl *cp, int cpu)
233 cpumask_clear_cpu(cpu, cp->free_cpus);
237 * cpudl_init - initialize the cpudl structure
238 * @cp: the cpudl max-heap context
240 int cpudl_init(struct cpudl *cp)
244 raw_spin_lock_init(&cp->lock);
247 cp->elements = kcalloc(nr_cpu_ids,
248 sizeof(struct cpudl_item),
253 if (!zalloc_cpumask_var(&cp->free_cpus, GFP_KERNEL)) {
258 for_each_possible_cpu(i)
259 cp->elements[i].idx = IDX_INVALID;
265 * cpudl_cleanup - clean up the cpudl structure
266 * @cp: the cpudl max-heap context
268 void cpudl_cleanup(struct cpudl *cp)
270 free_cpumask_var(cp->free_cpus);