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 /* track CPU usage of a group of tasks and its child groups */
25 struct cpuacct {
26 struct cgroup_subsys_state css;
27 /* cpuusage holds pointer to a u64-type object on every CPU */
28 u64 __percpu *cpuusage;
29 struct kernel_cpustat __percpu *cpustat;
30 };
31
css_ca(struct cgroup_subsys_state * css)32 static inline struct cpuacct *css_ca(struct cgroup_subsys_state *css)
33 {
34 return css ? container_of(css, struct cpuacct, css) : NULL;
35 }
36
37 /* Return CPU accounting group to which this task belongs */
task_ca(struct task_struct * tsk)38 static inline struct cpuacct *task_ca(struct task_struct *tsk)
39 {
40 return css_ca(task_css(tsk, cpuacct_cgrp_id));
41 }
42
parent_ca(struct cpuacct * ca)43 static inline struct cpuacct *parent_ca(struct cpuacct *ca)
44 {
45 return css_ca(ca->css.parent);
46 }
47
48 static DEFINE_PER_CPU(u64, root_cpuacct_cpuusage);
49 static struct cpuacct root_cpuacct = {
50 .cpustat = &kernel_cpustat,
51 .cpuusage = &root_cpuacct_cpuusage,
52 };
53
54 /* Create a new CPU accounting group */
55 static struct cgroup_subsys_state *
cpuacct_css_alloc(struct cgroup_subsys_state * parent_css)56 cpuacct_css_alloc(struct cgroup_subsys_state *parent_css)
57 {
58 struct cpuacct *ca;
59
60 if (!parent_css)
61 return &root_cpuacct.css;
62
63 ca = kzalloc(sizeof(*ca), GFP_KERNEL);
64 if (!ca)
65 goto out;
66
67 ca->cpuusage = alloc_percpu(u64);
68 if (!ca->cpuusage)
69 goto out_free_ca;
70
71 ca->cpustat = alloc_percpu(struct kernel_cpustat);
72 if (!ca->cpustat)
73 goto out_free_cpuusage;
74
75 return &ca->css;
76
77 out_free_cpuusage:
78 free_percpu(ca->cpuusage);
79 out_free_ca:
80 kfree(ca);
81 out:
82 return ERR_PTR(-ENOMEM);
83 }
84
85 /* Destroy an existing CPU accounting group */
cpuacct_css_free(struct cgroup_subsys_state * css)86 static void cpuacct_css_free(struct cgroup_subsys_state *css)
87 {
88 struct cpuacct *ca = css_ca(css);
89
90 free_percpu(ca->cpustat);
91 free_percpu(ca->cpuusage);
92 kfree(ca);
93 }
94
cpuacct_cpuusage_read(struct cpuacct * ca,int cpu,enum cpuacct_stat_index index)95 static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu,
96 enum cpuacct_stat_index index)
97 {
98 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
99 u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat;
100 u64 data;
101
102 /*
103 * We allow index == CPUACCT_STAT_NSTATS here to read
104 * the sum of usages.
105 */
106 BUG_ON(index > CPUACCT_STAT_NSTATS);
107
108 #ifndef CONFIG_64BIT
109 /*
110 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
111 */
112 raw_spin_rq_lock_irq(cpu_rq(cpu));
113 #endif
114
115 switch (index) {
116 case CPUACCT_STAT_USER:
117 data = cpustat[CPUTIME_USER] + cpustat[CPUTIME_NICE];
118 break;
119 case CPUACCT_STAT_SYSTEM:
120 data = cpustat[CPUTIME_SYSTEM] + cpustat[CPUTIME_IRQ] +
121 cpustat[CPUTIME_SOFTIRQ];
122 break;
123 case CPUACCT_STAT_NSTATS:
124 data = *cpuusage;
125 break;
126 }
127
128 #ifndef CONFIG_64BIT
129 raw_spin_rq_unlock_irq(cpu_rq(cpu));
130 #endif
131
132 return data;
133 }
134
cpuacct_cpuusage_write(struct cpuacct * ca,int cpu)135 static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu)
136 {
137 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
138 u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat;
139
140 /* Don't allow to reset global kernel_cpustat */
141 if (ca == &root_cpuacct)
142 return;
143
144 #ifndef CONFIG_64BIT
145 /*
146 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
147 */
148 raw_spin_rq_lock_irq(cpu_rq(cpu));
149 #endif
150 *cpuusage = 0;
151 cpustat[CPUTIME_USER] = cpustat[CPUTIME_NICE] = 0;
152 cpustat[CPUTIME_SYSTEM] = cpustat[CPUTIME_IRQ] = 0;
153 cpustat[CPUTIME_SOFTIRQ] = 0;
154
155 #ifndef CONFIG_64BIT
156 raw_spin_rq_unlock_irq(cpu_rq(cpu));
157 #endif
158 }
159
160 /* Return total CPU usage (in nanoseconds) of a group */
__cpuusage_read(struct cgroup_subsys_state * css,enum cpuacct_stat_index index)161 static u64 __cpuusage_read(struct cgroup_subsys_state *css,
162 enum cpuacct_stat_index index)
163 {
164 struct cpuacct *ca = css_ca(css);
165 u64 totalcpuusage = 0;
166 int i;
167
168 for_each_possible_cpu(i)
169 totalcpuusage += cpuacct_cpuusage_read(ca, i, index);
170
171 return totalcpuusage;
172 }
173
cpuusage_user_read(struct cgroup_subsys_state * css,struct cftype * cft)174 static u64 cpuusage_user_read(struct cgroup_subsys_state *css,
175 struct cftype *cft)
176 {
177 return __cpuusage_read(css, CPUACCT_STAT_USER);
178 }
179
cpuusage_sys_read(struct cgroup_subsys_state * css,struct cftype * cft)180 static u64 cpuusage_sys_read(struct cgroup_subsys_state *css,
181 struct cftype *cft)
182 {
183 return __cpuusage_read(css, CPUACCT_STAT_SYSTEM);
184 }
185
cpuusage_read(struct cgroup_subsys_state * css,struct cftype * cft)186 static u64 cpuusage_read(struct cgroup_subsys_state *css, struct cftype *cft)
187 {
188 return __cpuusage_read(css, CPUACCT_STAT_NSTATS);
189 }
190
cpuusage_write(struct cgroup_subsys_state * css,struct cftype * cft,u64 val)191 static int cpuusage_write(struct cgroup_subsys_state *css, struct cftype *cft,
192 u64 val)
193 {
194 struct cpuacct *ca = css_ca(css);
195 int cpu;
196
197 /*
198 * Only allow '0' here to do a reset.
199 */
200 if (val)
201 return -EINVAL;
202
203 for_each_possible_cpu(cpu)
204 cpuacct_cpuusage_write(ca, cpu);
205
206 return 0;
207 }
208
__cpuacct_percpu_seq_show(struct seq_file * m,enum cpuacct_stat_index index)209 static int __cpuacct_percpu_seq_show(struct seq_file *m,
210 enum cpuacct_stat_index index)
211 {
212 struct cpuacct *ca = css_ca(seq_css(m));
213 u64 percpu;
214 int i;
215
216 for_each_possible_cpu(i) {
217 percpu = cpuacct_cpuusage_read(ca, i, index);
218 seq_printf(m, "%llu ", (unsigned long long) percpu);
219 }
220 seq_printf(m, "\n");
221 return 0;
222 }
223
cpuacct_percpu_user_seq_show(struct seq_file * m,void * V)224 static int cpuacct_percpu_user_seq_show(struct seq_file *m, void *V)
225 {
226 return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_USER);
227 }
228
cpuacct_percpu_sys_seq_show(struct seq_file * m,void * V)229 static int cpuacct_percpu_sys_seq_show(struct seq_file *m, void *V)
230 {
231 return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_SYSTEM);
232 }
233
cpuacct_percpu_seq_show(struct seq_file * m,void * V)234 static int cpuacct_percpu_seq_show(struct seq_file *m, void *V)
235 {
236 return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_NSTATS);
237 }
238
cpuacct_all_seq_show(struct seq_file * m,void * V)239 static int cpuacct_all_seq_show(struct seq_file *m, void *V)
240 {
241 struct cpuacct *ca = css_ca(seq_css(m));
242 int index;
243 int cpu;
244
245 seq_puts(m, "cpu");
246 for (index = 0; index < CPUACCT_STAT_NSTATS; index++)
247 seq_printf(m, " %s", cpuacct_stat_desc[index]);
248 seq_puts(m, "\n");
249
250 for_each_possible_cpu(cpu) {
251 seq_printf(m, "%d", cpu);
252 for (index = 0; index < CPUACCT_STAT_NSTATS; index++)
253 seq_printf(m, " %llu",
254 cpuacct_cpuusage_read(ca, cpu, index));
255 seq_puts(m, "\n");
256 }
257 return 0;
258 }
259
cpuacct_stats_show(struct seq_file * sf,void * v)260 static int cpuacct_stats_show(struct seq_file *sf, void *v)
261 {
262 struct cpuacct *ca = css_ca(seq_css(sf));
263 s64 val[CPUACCT_STAT_NSTATS];
264 int cpu;
265 int stat;
266
267 memset(val, 0, sizeof(val));
268 for_each_possible_cpu(cpu) {
269 u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat;
270
271 val[CPUACCT_STAT_USER] += cpustat[CPUTIME_USER];
272 val[CPUACCT_STAT_USER] += cpustat[CPUTIME_NICE];
273 val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_SYSTEM];
274 val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_IRQ];
275 val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_SOFTIRQ];
276 }
277
278 for (stat = 0; stat < CPUACCT_STAT_NSTATS; stat++) {
279 seq_printf(sf, "%s %lld\n",
280 cpuacct_stat_desc[stat],
281 (long long)nsec_to_clock_t(val[stat]));
282 }
283
284 return 0;
285 }
286
287 static struct cftype files[] = {
288 {
289 .name = "usage",
290 .read_u64 = cpuusage_read,
291 .write_u64 = cpuusage_write,
292 },
293 {
294 .name = "usage_user",
295 .read_u64 = cpuusage_user_read,
296 },
297 {
298 .name = "usage_sys",
299 .read_u64 = cpuusage_sys_read,
300 },
301 {
302 .name = "usage_percpu",
303 .seq_show = cpuacct_percpu_seq_show,
304 },
305 {
306 .name = "usage_percpu_user",
307 .seq_show = cpuacct_percpu_user_seq_show,
308 },
309 {
310 .name = "usage_percpu_sys",
311 .seq_show = cpuacct_percpu_sys_seq_show,
312 },
313 {
314 .name = "usage_all",
315 .seq_show = cpuacct_all_seq_show,
316 },
317 {
318 .name = "stat",
319 .seq_show = cpuacct_stats_show,
320 },
321 { } /* terminate */
322 };
323
324 /*
325 * charge this task's execution time to its accounting group.
326 *
327 * called with rq->lock held.
328 */
cpuacct_charge(struct task_struct * tsk,u64 cputime)329 void cpuacct_charge(struct task_struct *tsk, u64 cputime)
330 {
331 unsigned int cpu = task_cpu(tsk);
332 struct cpuacct *ca;
333
334 lockdep_assert_rq_held(cpu_rq(cpu));
335
336 for (ca = task_ca(tsk); ca; ca = parent_ca(ca))
337 *per_cpu_ptr(ca->cpuusage, cpu) += cputime;
338 }
339
340 /*
341 * Add user/system time to cpuacct.
342 *
343 * Note: it's the caller that updates the account of the root cgroup.
344 */
cpuacct_account_field(struct task_struct * tsk,int index,u64 val)345 void cpuacct_account_field(struct task_struct *tsk, int index, u64 val)
346 {
347 struct cpuacct *ca;
348
349 rcu_read_lock();
350 for (ca = task_ca(tsk); ca != &root_cpuacct; ca = parent_ca(ca))
351 __this_cpu_add(ca->cpustat->cpustat[index], val);
352 rcu_read_unlock();
353 }
354
355 struct cgroup_subsys cpuacct_cgrp_subsys = {
356 .css_alloc = cpuacct_css_alloc,
357 .css_free = cpuacct_css_free,
358 .legacy_cftypes = files,
359 .early_init = true,
360 };
361