Move some files so the vanilla kernel builds again.
[projects/modsched/linux.git] / kernel / sched / cfs / cpudeadline.c
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  */
13
14 #include <linux/gfp.h>
15 #include <linux/kernel.h>
16 #include <linux/slab.h>
17 #include "cpudeadline.h"
18
19 static inline int parent(int i)
20 {
21         return (i - 1) >> 1;
22 }
23
24 static inline int left_child(int i)
25 {
26         return (i << 1) + 1;
27 }
28
29 static inline int right_child(int i)
30 {
31         return (i << 1) + 2;
32 }
33
34 static void cpudl_exchange(struct cpudl *cp, int a, int b)
35 {
36         int cpu_a = cp->elements[a].cpu, cpu_b = cp->elements[b].cpu;
37
38         swap(cp->elements[a].cpu, cp->elements[b].cpu);
39         swap(cp->elements[a].dl , cp->elements[b].dl );
40
41         swap(cp->elements[cpu_a].idx, cp->elements[cpu_b].idx);
42 }
43
44 static void cpudl_heapify(struct cpudl *cp, int idx)
45 {
46         int l, r, largest;
47
48         /* adapted from lib/prio_heap.c */
49         while(1) {
50                 l = left_child(idx);
51                 r = right_child(idx);
52                 largest = idx;
53
54                 if ((l < cp->size) && dl_time_before(cp->elements[idx].dl,
55                                                         cp->elements[l].dl))
56                         largest = l;
57                 if ((r < cp->size) && dl_time_before(cp->elements[largest].dl,
58                                                         cp->elements[r].dl))
59                         largest = r;
60                 if (largest == idx)
61                         break;
62
63                 /* Push idx down the heap one level and bump one up */
64                 cpudl_exchange(cp, largest, idx);
65                 idx = largest;
66         }
67 }
68
69 static void cpudl_change_key(struct cpudl *cp, int idx, u64 new_dl)
70 {
71         WARN_ON(idx == IDX_INVALID || !cpu_present(idx));
72
73         if (dl_time_before(new_dl, cp->elements[idx].dl)) {
74                 cp->elements[idx].dl = new_dl;
75                 cpudl_heapify(cp, idx);
76         } else {
77                 cp->elements[idx].dl = new_dl;
78                 while (idx > 0 && dl_time_before(cp->elements[parent(idx)].dl,
79                                         cp->elements[idx].dl)) {
80                         cpudl_exchange(cp, idx, parent(idx));
81                         idx = parent(idx);
82                 }
83         }
84 }
85
86 static inline int cpudl_maximum(struct cpudl *cp)
87 {
88         return cp->elements[0].cpu;
89 }
90
91 /*
92  * cpudl_find - find the best (later-dl) CPU in the system
93  * @cp: the cpudl max-heap context
94  * @p: the task
95  * @later_mask: a mask to fill in with the selected CPUs (or NULL)
96  *
97  * Returns: int - best CPU (heap maximum if suitable)
98  */
99 int cpudl_find(struct cpudl *cp, struct task_struct *p,
100                struct cpumask *later_mask)
101 {
102         int best_cpu = -1;
103         const struct sched_dl_entity *dl_se = &p->dl;
104
105         if (later_mask &&
106             cpumask_and(later_mask, cp->free_cpus, &p->cpus_allowed)) {
107                 best_cpu = cpumask_any(later_mask);
108                 goto out;
109         } else if (cpumask_test_cpu(cpudl_maximum(cp), &p->cpus_allowed) &&
110                         dl_time_before(dl_se->deadline, cp->elements[0].dl)) {
111                 best_cpu = cpudl_maximum(cp);
112                 if (later_mask)
113                         cpumask_set_cpu(best_cpu, later_mask);
114         }
115
116 out:
117         WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));
118
119         return best_cpu;
120 }
121
122 /*
123  * cpudl_set - update the cpudl max-heap
124  * @cp: the cpudl max-heap context
125  * @cpu: the target cpu
126  * @dl: the new earliest deadline for this cpu
127  *
128  * Notes: assumes cpu_rq(cpu)->lock is locked
129  *
130  * Returns: (void)
131  */
132 void cpudl_set(struct cpudl *cp, int cpu, u64 dl, int is_valid)
133 {
134         int old_idx, new_cpu;
135         unsigned long flags;
136
137         WARN_ON(!cpu_present(cpu));
138
139         raw_spin_lock_irqsave(&cp->lock, flags);
140         old_idx = cp->elements[cpu].idx;
141         if (!is_valid) {
142                 /* remove item */
143                 if (old_idx == IDX_INVALID) {
144                         /*
145                          * Nothing to remove if old_idx was invalid.
146                          * This could happen if a rq_offline_dl is
147                          * called for a CPU without -dl tasks running.
148                          */
149                         goto out;
150                 }
151                 new_cpu = cp->elements[cp->size - 1].cpu;
152                 cp->elements[old_idx].dl = cp->elements[cp->size - 1].dl;
153                 cp->elements[old_idx].cpu = new_cpu;
154                 cp->size--;
155                 cp->elements[new_cpu].idx = old_idx;
156                 cp->elements[cpu].idx = IDX_INVALID;
157                 while (old_idx > 0 && dl_time_before(
158                                 cp->elements[parent(old_idx)].dl,
159                                 cp->elements[old_idx].dl)) {
160                         cpudl_exchange(cp, old_idx, parent(old_idx));
161                         old_idx = parent(old_idx);
162                 }
163                 cpumask_set_cpu(cpu, cp->free_cpus);
164                 cpudl_heapify(cp, old_idx);
165
166                 goto out;
167         }
168
169         if (old_idx == IDX_INVALID) {
170                 cp->size++;
171                 cp->elements[cp->size - 1].dl = 0;
172                 cp->elements[cp->size - 1].cpu = cpu;
173                 cp->elements[cpu].idx = cp->size - 1;
174                 cpudl_change_key(cp, cp->size - 1, dl);
175                 cpumask_clear_cpu(cpu, cp->free_cpus);
176         } else {
177                 cpudl_change_key(cp, old_idx, dl);
178         }
179
180 out:
181         raw_spin_unlock_irqrestore(&cp->lock, flags);
182 }
183
184 /*
185  * cpudl_set_freecpu - Set the cpudl.free_cpus
186  * @cp: the cpudl max-heap context
187  * @cpu: rd attached cpu
188  */
189 void cpudl_set_freecpu(struct cpudl *cp, int cpu)
190 {
191         cpumask_set_cpu(cpu, cp->free_cpus);
192 }
193
194 /*
195  * cpudl_clear_freecpu - Clear the cpudl.free_cpus
196  * @cp: the cpudl max-heap context
197  * @cpu: rd attached cpu
198  */
199 void cpudl_clear_freecpu(struct cpudl *cp, int cpu)
200 {
201         cpumask_clear_cpu(cpu, cp->free_cpus);
202 }
203
204 /*
205  * cpudl_init - initialize the cpudl structure
206  * @cp: the cpudl max-heap context
207  */
208 int cpudl_init(struct cpudl *cp)
209 {
210         int i;
211
212         memset(cp, 0, sizeof(*cp));
213         raw_spin_lock_init(&cp->lock);
214         cp->size = 0;
215
216         cp->elements = kcalloc(nr_cpu_ids,
217                                sizeof(struct cpudl_item),
218                                GFP_KERNEL);
219         if (!cp->elements)
220                 return -ENOMEM;
221
222         if (!zalloc_cpumask_var(&cp->free_cpus, GFP_KERNEL)) {
223                 kfree(cp->elements);
224                 return -ENOMEM;
225         }
226
227         for_each_possible_cpu(i)
228                 cp->elements[i].idx = IDX_INVALID;
229
230         return 0;
231 }
232
233 /*
234  * cpudl_cleanup - clean up the cpudl structure
235  * @cp: the cpudl max-heap context
236  */
237 void cpudl_cleanup(struct cpudl *cp)
238 {
239         free_cpumask_var(cp->free_cpus);
240         kfree(cp->elements);
241 }