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