1// SPDX-License-Identifier: GPL-2.0
2/*
3 * CPU accounting code for task groups.
4 *
5 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
6 * (balbir@in.ibm.com).
7 */
8#include "sched.h"
9
10/* Time spent by the tasks of the CPU accounting group executing in ... */
11enum cpuacct_stat_index {
12 CPUACCT_STAT_USER, /* ... user mode */
13 CPUACCT_STAT_SYSTEM, /* ... kernel mode */
14
15 CPUACCT_STAT_NSTATS,
16};
17
18static const char * const cpuacct_stat_desc[] = {
19 [CPUACCT_STAT_USER] = "user",
20 [CPUACCT_STAT_SYSTEM] = "system",
21};
22
23struct cpuacct_usage {
24 u64 usages[CPUACCT_STAT_NSTATS];
25};
26
27/* track CPU usage of a group of tasks and its child groups */
28struct cpuacct {
29 struct cgroup_subsys_state css;
30 /* cpuusage holds pointer to a u64-type object on every CPU */
31 struct cpuacct_usage __percpu *cpuusage;
32 struct kernel_cpustat __percpu *cpustat;
33};
34
35static inline struct cpuacct *css_ca(struct cgroup_subsys_state *css)
36{
37 return css ? container_of(css, struct cpuacct, css) : NULL;
38}
39
40/* Return CPU accounting group to which this task belongs */
41static inline struct cpuacct *task_ca(struct task_struct *tsk)
42{
43 return css_ca(task_css(tsk, cpuacct_cgrp_id));
44}
45
46static inline struct cpuacct *parent_ca(struct cpuacct *ca)
47{
48 return css_ca(ca->css.parent);
49}
50
51static DEFINE_PER_CPU(struct cpuacct_usage, root_cpuacct_cpuusage);
52static struct cpuacct root_cpuacct = {
53 .cpustat = &kernel_cpustat,
54 .cpuusage = &root_cpuacct_cpuusage,
55};
56
57/* Create a new CPU accounting group */
58static struct cgroup_subsys_state *
59cpuacct_css_alloc(struct cgroup_subsys_state *parent_css)
60{
61 struct cpuacct *ca;
62
63 if (!parent_css)
64 return &root_cpuacct.css;
65
66 ca = kzalloc(sizeof(*ca), GFP_KERNEL);
67 if (!ca)
68 goto out;
69
70 ca->cpuusage = alloc_percpu(struct cpuacct_usage);
71 if (!ca->cpuusage)
72 goto out_free_ca;
73
74 ca->cpustat = alloc_percpu(struct kernel_cpustat);
75 if (!ca->cpustat)
76 goto out_free_cpuusage;
77
78 return &ca->css;
79
80out_free_cpuusage:
81 free_percpu(ca->cpuusage);
82out_free_ca:
83 kfree(ca);
84out:
85 return ERR_PTR(-ENOMEM);
86}
87
88/* Destroy an existing CPU accounting group */
89static void cpuacct_css_free(struct cgroup_subsys_state *css)
90{
91 struct cpuacct *ca = css_ca(css);
92
93 free_percpu(ca->cpustat);
94 free_percpu(ca->cpuusage);
95 kfree(ca);
96}
97
98static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu,
99 enum cpuacct_stat_index index)
100{
101 struct cpuacct_usage *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
102 u64 data;
103
104 /*
105 * We allow index == CPUACCT_STAT_NSTATS here to read
106 * the sum of suages.
107 */
108 BUG_ON(index > CPUACCT_STAT_NSTATS);
109
110#ifndef CONFIG_64BIT
111 /*
112 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
113 */
114 raw_spin_lock_irq(&cpu_rq(cpu)->lock);
115#endif
116
117 if (index == CPUACCT_STAT_NSTATS) {
118 int i = 0;
119
120 data = 0;
121 for (i = 0; i < CPUACCT_STAT_NSTATS; i++)
122 data += cpuusage->usages[i];
123 } else {
124 data = cpuusage->usages[index];
125 }
126
127#ifndef CONFIG_64BIT
128 raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
129#endif
130
131 return data;
132}
133
134static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
135{
136 struct cpuacct_usage *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
137 int i;
138
139#ifndef CONFIG_64BIT
140 /*
141 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
142 */
143 raw_spin_lock_irq(&cpu_rq(cpu)->lock);
144#endif
145
146 for (i = 0; i < CPUACCT_STAT_NSTATS; i++)
147 cpuusage->usages[i] = val;
148
149#ifndef CONFIG_64BIT
150 raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
151#endif
152}
153
154/* Return total CPU usage (in nanoseconds) of a group */
155static u64 __cpuusage_read(struct cgroup_subsys_state *css,
156 enum cpuacct_stat_index index)
157{
158 struct cpuacct *ca = css_ca(css);
159 u64 totalcpuusage = 0;
160 int i;
161
162 for_each_possible_cpu(i)
163 totalcpuusage += cpuacct_cpuusage_read(ca, i, index);
164
165 return totalcpuusage;
166}
167
168static u64 cpuusage_user_read(struct cgroup_subsys_state *css,
169 struct cftype *cft)
170{
171 return __cpuusage_read(css, CPUACCT_STAT_USER);
172}
173
174static u64 cpuusage_sys_read(struct cgroup_subsys_state *css,
175 struct cftype *cft)
176{
177 return __cpuusage_read(css, CPUACCT_STAT_SYSTEM);
178}
179
180static u64 cpuusage_read(struct cgroup_subsys_state *css, struct cftype *cft)
181{
182 return __cpuusage_read(css, CPUACCT_STAT_NSTATS);
183}
184
185static int cpuusage_write(struct cgroup_subsys_state *css, struct cftype *cft,
186 u64 val)
187{
188 struct cpuacct *ca = css_ca(css);
189 int cpu;
190
191 /*
192 * Only allow '0' here to do a reset.
193 */
194 if (val)
195 return -EINVAL;
196
197 for_each_possible_cpu(cpu)
198 cpuacct_cpuusage_write(ca, cpu, 0);
199
200 return 0;
201}
202
203static int __cpuacct_percpu_seq_show(struct seq_file *m,
204 enum cpuacct_stat_index index)
205{
206 struct cpuacct *ca = css_ca(seq_css(m));
207 u64 percpu;
208 int i;
209
210 for_each_possible_cpu(i) {
211 percpu = cpuacct_cpuusage_read(ca, i, index);
212 seq_printf(m, "%llu ", (unsigned long long) percpu);
213 }
214 seq_printf(m, "\n");
215 return 0;
216}
217
218static int cpuacct_percpu_user_seq_show(struct seq_file *m, void *V)
219{
220 return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_USER);
221}
222
223static int cpuacct_percpu_sys_seq_show(struct seq_file *m, void *V)
224{
225 return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_SYSTEM);
226}
227
228static int cpuacct_percpu_seq_show(struct seq_file *m, void *V)
229{
230 return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_NSTATS);
231}
232
233static int cpuacct_all_seq_show(struct seq_file *m, void *V)
234{
235 struct cpuacct *ca = css_ca(seq_css(m));
236 int index;
237 int cpu;
238
239 seq_puts(m, "cpu");
240 for (index = 0; index < CPUACCT_STAT_NSTATS; index++)
241 seq_printf(m, " %s", cpuacct_stat_desc[index]);
242 seq_puts(m, "\n");
243
244 for_each_possible_cpu(cpu) {
245 struct cpuacct_usage *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
246
247 seq_printf(m, "%d", cpu);
248
249 for (index = 0; index < CPUACCT_STAT_NSTATS; index++) {
250#ifndef CONFIG_64BIT
251 /*
252 * Take rq->lock to make 64-bit read safe on 32-bit
253 * platforms.
254 */
255 raw_spin_lock_irq(&cpu_rq(cpu)->lock);
256#endif
257
258 seq_printf(m, " %llu", cpuusage->usages[index]);
259
260#ifndef CONFIG_64BIT
261 raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
262#endif
263 }
264 seq_puts(m, "\n");
265 }
266 return 0;
267}
268
269static int cpuacct_stats_show(struct seq_file *sf, void *v)
270{
271 struct cpuacct *ca = css_ca(seq_css(sf));
272 s64 val[CPUACCT_STAT_NSTATS];
273 int cpu;
274 int stat;
275
276 memset(val, 0, sizeof(val));
277 for_each_possible_cpu(cpu) {
278 u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat;
279
280 val[CPUACCT_STAT_USER] += cpustat[CPUTIME_USER];
281 val[CPUACCT_STAT_USER] += cpustat[CPUTIME_NICE];
282 val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_SYSTEM];
283 val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_IRQ];
284 val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_SOFTIRQ];
285 }
286
287 for (stat = 0; stat < CPUACCT_STAT_NSTATS; stat++) {
288 seq_printf(sf, "%s %lld\n",
289 cpuacct_stat_desc[stat],
290 (long long)nsec_to_clock_t(val[stat]));
291 }
292
293 return 0;
294}
295
296static struct cftype files[] = {
297 {
298 .name = "usage",
299 .read_u64 = cpuusage_read,
300 .write_u64 = cpuusage_write,
301 },
302 {
303 .name = "usage_user",
304 .read_u64 = cpuusage_user_read,
305 },
306 {
307 .name = "usage_sys",
308 .read_u64 = cpuusage_sys_read,
309 },
310 {
311 .name = "usage_percpu",
312 .seq_show = cpuacct_percpu_seq_show,
313 },
314 {
315 .name = "usage_percpu_user",
316 .seq_show = cpuacct_percpu_user_seq_show,
317 },
318 {
319 .name = "usage_percpu_sys",
320 .seq_show = cpuacct_percpu_sys_seq_show,
321 },
322 {
323 .name = "usage_all",
324 .seq_show = cpuacct_all_seq_show,
325 },
326 {
327 .name = "stat",
328 .seq_show = cpuacct_stats_show,
329 },
330 { } /* terminate */
331};
332
333/*
334 * charge this task's execution time to its accounting group.
335 *
336 * called with rq->lock held.
337 */
338void cpuacct_charge(struct task_struct *tsk, u64 cputime)
339{
340 struct cpuacct *ca;
341 int index = CPUACCT_STAT_SYSTEM;
342 struct pt_regs *regs = task_pt_regs(tsk);
343
344 if (regs && user_mode(regs))
345 index = CPUACCT_STAT_USER;
346
347 rcu_read_lock();
348
349 for (ca = task_ca(tsk); ca; ca = parent_ca(ca))
350 this_cpu_ptr(ca->cpuusage)->usages[index] += cputime;
351
352 rcu_read_unlock();
353}
354
355/*
356 * Add user/system time to cpuacct.
357 *
358 * Note: it's the caller that updates the account of the root cgroup.
359 */
360void cpuacct_account_field(struct task_struct *tsk, int index, u64 val)
361{
362 struct cpuacct *ca;
363
364 rcu_read_lock();
365 for (ca = task_ca(tsk); ca != &root_cpuacct; ca = parent_ca(ca))
366 this_cpu_ptr(ca->cpustat)->cpustat[index] += val;
367 rcu_read_unlock();
368}
369
370struct cgroup_subsys cpuacct_cgrp_subsys = {
371 .css_alloc = cpuacct_css_alloc,
372 .css_free = cpuacct_css_free,
373 .legacy_cftypes = files,
374 .early_init = true,
375};
376