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1#include <linux/cgroup.h>
2#include <linux/slab.h>
3#include <linux/percpu.h>
4#include <linux/spinlock.h>
5#include <linux/cpumask.h>
6#include <linux/seq_file.h>
7#include <linux/rcupdate.h>
8#include <linux/kernel_stat.h>
9#include <linux/err.h>
10
11#include "sched.h"
12
13/*
14 * CPU accounting code for task groups.
15 *
16 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
17 * (balbir@in.ibm.com).
18 */
19
20/* Time spent by the tasks of the cpu accounting group executing in ... */
21enum cpuacct_stat_index {
22 CPUACCT_STAT_USER, /* ... user mode */
23 CPUACCT_STAT_SYSTEM, /* ... kernel mode */
24
25 CPUACCT_STAT_NSTATS,
26};
27
28static const char * const cpuacct_stat_desc[] = {
29 [CPUACCT_STAT_USER] = "user",
30 [CPUACCT_STAT_SYSTEM] = "system",
31};
32
33struct cpuacct_usage {
34 u64 usages[CPUACCT_STAT_NSTATS];
35};
36
37/* track cpu usage of a group of tasks and its child groups */
38struct cpuacct {
39 struct cgroup_subsys_state css;
40 /* cpuusage holds pointer to a u64-type object on every cpu */
41 struct cpuacct_usage __percpu *cpuusage;
42 struct kernel_cpustat __percpu *cpustat;
43};
44
45static inline struct cpuacct *css_ca(struct cgroup_subsys_state *css)
46{
47 return css ? container_of(css, struct cpuacct, css) : NULL;
48}
49
50/* return cpu accounting group to which this task belongs */
51static inline struct cpuacct *task_ca(struct task_struct *tsk)
52{
53 return css_ca(task_css(tsk, cpuacct_cgrp_id));
54}
55
56static inline struct cpuacct *parent_ca(struct cpuacct *ca)
57{
58 return css_ca(ca->css.parent);
59}
60
61static DEFINE_PER_CPU(struct cpuacct_usage, root_cpuacct_cpuusage);
62static struct cpuacct root_cpuacct = {
63 .cpustat = &kernel_cpustat,
64 .cpuusage = &root_cpuacct_cpuusage,
65};
66
67/* create a new cpu accounting group */
68static struct cgroup_subsys_state *
69cpuacct_css_alloc(struct cgroup_subsys_state *parent_css)
70{
71 struct cpuacct *ca;
72
73 if (!parent_css)
74 return &root_cpuacct.css;
75
76 ca = kzalloc(sizeof(*ca), GFP_KERNEL);
77 if (!ca)
78 goto out;
79
80 ca->cpuusage = alloc_percpu(struct cpuacct_usage);
81 if (!ca->cpuusage)
82 goto out_free_ca;
83
84 ca->cpustat = alloc_percpu(struct kernel_cpustat);
85 if (!ca->cpustat)
86 goto out_free_cpuusage;
87
88 return &ca->css;
89
90out_free_cpuusage:
91 free_percpu(ca->cpuusage);
92out_free_ca:
93 kfree(ca);
94out:
95 return ERR_PTR(-ENOMEM);
96}
97
98/* destroy an existing cpu accounting group */
99static void cpuacct_css_free(struct cgroup_subsys_state *css)
100{
101 struct cpuacct *ca = css_ca(css);
102
103 free_percpu(ca->cpustat);
104 free_percpu(ca->cpuusage);
105 kfree(ca);
106}
107
108static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu,
109 enum cpuacct_stat_index index)
110{
111 struct cpuacct_usage *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
112 u64 data;
113
114 /*
115 * We allow index == CPUACCT_STAT_NSTATS here to read
116 * the sum of suages.
117 */
118 BUG_ON(index > CPUACCT_STAT_NSTATS);
119
120#ifndef CONFIG_64BIT
121 /*
122 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
123 */
124 raw_spin_lock_irq(&cpu_rq(cpu)->lock);
125#endif
126
127 if (index == CPUACCT_STAT_NSTATS) {
128 int i = 0;
129
130 data = 0;
131 for (i = 0; i < CPUACCT_STAT_NSTATS; i++)
132 data += cpuusage->usages[i];
133 } else {
134 data = cpuusage->usages[index];
135 }
136
137#ifndef CONFIG_64BIT
138 raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
139#endif
140
141 return data;
142}
143
144static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
145{
146 struct cpuacct_usage *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
147 int i;
148
149#ifndef CONFIG_64BIT
150 /*
151 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
152 */
153 raw_spin_lock_irq(&cpu_rq(cpu)->lock);
154#endif
155
156 for (i = 0; i < CPUACCT_STAT_NSTATS; i++)
157 cpuusage->usages[i] = val;
158
159#ifndef CONFIG_64BIT
160 raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
161#endif
162}
163
164/* return total cpu usage (in nanoseconds) of a group */
165static u64 __cpuusage_read(struct cgroup_subsys_state *css,
166 enum cpuacct_stat_index index)
167{
168 struct cpuacct *ca = css_ca(css);
169 u64 totalcpuusage = 0;
170 int i;
171
172 for_each_possible_cpu(i)
173 totalcpuusage += cpuacct_cpuusage_read(ca, i, index);
174
175 return totalcpuusage;
176}
177
178static u64 cpuusage_user_read(struct cgroup_subsys_state *css,
179 struct cftype *cft)
180{
181 return __cpuusage_read(css, CPUACCT_STAT_USER);
182}
183
184static u64 cpuusage_sys_read(struct cgroup_subsys_state *css,
185 struct cftype *cft)
186{
187 return __cpuusage_read(css, CPUACCT_STAT_SYSTEM);
188}
189
190static u64 cpuusage_read(struct cgroup_subsys_state *css, struct cftype *cft)
191{
192 return __cpuusage_read(css, CPUACCT_STAT_NSTATS);
193}
194
195static int cpuusage_write(struct cgroup_subsys_state *css, struct cftype *cft,
196 u64 val)
197{
198 struct cpuacct *ca = css_ca(css);
199 int cpu;
200
201 /*
202 * Only allow '0' here to do a reset.
203 */
204 if (val)
205 return -EINVAL;
206
207 for_each_possible_cpu(cpu)
208 cpuacct_cpuusage_write(ca, cpu, 0);
209
210 return 0;
211}
212
213static int __cpuacct_percpu_seq_show(struct seq_file *m,
214 enum cpuacct_stat_index index)
215{
216 struct cpuacct *ca = css_ca(seq_css(m));
217 u64 percpu;
218 int i;
219
220 for_each_possible_cpu(i) {
221 percpu = cpuacct_cpuusage_read(ca, i, index);
222 seq_printf(m, "%llu ", (unsigned long long) percpu);
223 }
224 seq_printf(m, "\n");
225 return 0;
226}
227
228static int cpuacct_percpu_user_seq_show(struct seq_file *m, void *V)
229{
230 return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_USER);
231}
232
233static int cpuacct_percpu_sys_seq_show(struct seq_file *m, void *V)
234{
235 return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_SYSTEM);
236}
237
238static int cpuacct_percpu_seq_show(struct seq_file *m, void *V)
239{
240 return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_NSTATS);
241}
242
243static int cpuacct_all_seq_show(struct seq_file *m, void *V)
244{
245 struct cpuacct *ca = css_ca(seq_css(m));
246 int index;
247 int cpu;
248
249 seq_puts(m, "cpu");
250 for (index = 0; index < CPUACCT_STAT_NSTATS; index++)
251 seq_printf(m, " %s", cpuacct_stat_desc[index]);
252 seq_puts(m, "\n");
253
254 for_each_possible_cpu(cpu) {
255 struct cpuacct_usage *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
256
257 seq_printf(m, "%d", cpu);
258
259 for (index = 0; index < CPUACCT_STAT_NSTATS; index++) {
260#ifndef CONFIG_64BIT
261 /*
262 * Take rq->lock to make 64-bit read safe on 32-bit
263 * platforms.
264 */
265 raw_spin_lock_irq(&cpu_rq(cpu)->lock);
266#endif
267
268 seq_printf(m, " %llu", cpuusage->usages[index]);
269
270#ifndef CONFIG_64BIT
271 raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
272#endif
273 }
274 seq_puts(m, "\n");
275 }
276 return 0;
277}
278
279static int cpuacct_stats_show(struct seq_file *sf, void *v)
280{
281 struct cpuacct *ca = css_ca(seq_css(sf));
282 s64 val[CPUACCT_STAT_NSTATS];
283 int cpu;
284 int stat;
285
286 memset(val, 0, sizeof(val));
287 for_each_possible_cpu(cpu) {
288 u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat;
289
290 val[CPUACCT_STAT_USER] += cpustat[CPUTIME_USER];
291 val[CPUACCT_STAT_USER] += cpustat[CPUTIME_NICE];
292 val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_SYSTEM];
293 val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_IRQ];
294 val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_SOFTIRQ];
295 }
296
297 for (stat = 0; stat < CPUACCT_STAT_NSTATS; stat++) {
298 seq_printf(sf, "%s %lld\n",
299 cpuacct_stat_desc[stat],
300 (long long)cputime64_to_clock_t(val[stat]));
301 }
302
303 return 0;
304}
305
306static struct cftype files[] = {
307 {
308 .name = "usage",
309 .read_u64 = cpuusage_read,
310 .write_u64 = cpuusage_write,
311 },
312 {
313 .name = "usage_user",
314 .read_u64 = cpuusage_user_read,
315 },
316 {
317 .name = "usage_sys",
318 .read_u64 = cpuusage_sys_read,
319 },
320 {
321 .name = "usage_percpu",
322 .seq_show = cpuacct_percpu_seq_show,
323 },
324 {
325 .name = "usage_percpu_user",
326 .seq_show = cpuacct_percpu_user_seq_show,
327 },
328 {
329 .name = "usage_percpu_sys",
330 .seq_show = cpuacct_percpu_sys_seq_show,
331 },
332 {
333 .name = "usage_all",
334 .seq_show = cpuacct_all_seq_show,
335 },
336 {
337 .name = "stat",
338 .seq_show = cpuacct_stats_show,
339 },
340 { } /* terminate */
341};
342
343/*
344 * charge this task's execution time to its accounting group.
345 *
346 * called with rq->lock held.
347 */
348void cpuacct_charge(struct task_struct *tsk, u64 cputime)
349{
350 struct cpuacct *ca;
351 int index = CPUACCT_STAT_SYSTEM;
352 struct pt_regs *regs = task_pt_regs(tsk);
353
354 if (regs && user_mode(regs))
355 index = CPUACCT_STAT_USER;
356
357 rcu_read_lock();
358
359 for (ca = task_ca(tsk); ca; ca = parent_ca(ca))
360 this_cpu_ptr(ca->cpuusage)->usages[index] += cputime;
361
362 rcu_read_unlock();
363}
364
365/*
366 * Add user/system time to cpuacct.
367 *
368 * Note: it's the caller that updates the account of the root cgroup.
369 */
370void cpuacct_account_field(struct task_struct *tsk, int index, u64 val)
371{
372 struct cpuacct *ca;
373
374 rcu_read_lock();
375 for (ca = task_ca(tsk); ca != &root_cpuacct; ca = parent_ca(ca))
376 this_cpu_ptr(ca->cpustat)->cpustat[index] += val;
377 rcu_read_unlock();
378}
379
380struct cgroup_subsys cpuacct_cgrp_subsys = {
381 .css_alloc = cpuacct_css_alloc,
382 .css_free = cpuacct_css_free,
383 .legacy_cftypes = files,
384 .early_init = true,
385};