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