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>
13 * CPU accounting code for task groups.
15 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
16 * (balbir@in.ibm.com).
19 /* Time spent by the tasks of the cpu accounting group executing in ... */
20 enum cpuacct_stat_index {
21 CPUACCT_STAT_USER, /* ... user mode */
22 CPUACCT_STAT_SYSTEM, /* ... kernel mode */
27 /* track cpu usage of a group of tasks and its child groups */
29 struct cgroup_subsys_state css;
30 /* cpuusage holds pointer to a u64-type object on every cpu */
31 u64 __percpu *cpuusage;
32 struct kernel_cpustat __percpu *cpustat;
35 /* return cpu accounting group corresponding to this container */
36 static inline struct cpuacct *cgroup_ca(struct cgroup *cgrp)
38 return container_of(cgroup_subsys_state(cgrp, cpuacct_subsys_id),
42 /* return cpu accounting group to which this task belongs */
43 static inline struct cpuacct *task_ca(struct task_struct *tsk)
45 return container_of(task_subsys_state(tsk, cpuacct_subsys_id),
49 static inline struct cpuacct *__parent_ca(struct cpuacct *ca)
51 return cgroup_ca(ca->css.cgroup->parent);
54 static inline struct cpuacct *parent_ca(struct cpuacct *ca)
56 if (!ca->css.cgroup->parent)
58 return cgroup_ca(ca->css.cgroup->parent);
61 static DEFINE_PER_CPU(u64, root_cpuacct_cpuusage);
62 static struct cpuacct root_cpuacct;
64 /* create a new cpu accounting group */
65 static struct cgroup_subsys_state *cpuacct_css_alloc(struct cgroup *cgrp)
70 return &root_cpuacct.css;
72 ca = kzalloc(sizeof(*ca), GFP_KERNEL);
76 ca->cpuusage = alloc_percpu(u64);
80 ca->cpustat = alloc_percpu(struct kernel_cpustat);
82 goto out_free_cpuusage;
87 free_percpu(ca->cpuusage);
91 return ERR_PTR(-ENOMEM);
94 /* destroy an existing cpu accounting group */
95 static void cpuacct_css_free(struct cgroup *cgrp)
97 struct cpuacct *ca = cgroup_ca(cgrp);
99 free_percpu(ca->cpustat);
100 free_percpu(ca->cpuusage);
104 static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu)
106 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
111 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
113 raw_spin_lock_irq(&cpu_rq(cpu)->lock);
115 raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
123 static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
125 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
129 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
131 raw_spin_lock_irq(&cpu_rq(cpu)->lock);
133 raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
139 /* return total cpu usage (in nanoseconds) of a group */
140 static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft)
142 struct cpuacct *ca = cgroup_ca(cgrp);
143 u64 totalcpuusage = 0;
146 for_each_present_cpu(i)
147 totalcpuusage += cpuacct_cpuusage_read(ca, i);
149 return totalcpuusage;
152 static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype,
155 struct cpuacct *ca = cgroup_ca(cgrp);
164 for_each_present_cpu(i)
165 cpuacct_cpuusage_write(ca, i, 0);
171 static int cpuacct_percpu_seq_read(struct cgroup *cgroup, struct cftype *cft,
174 struct cpuacct *ca = cgroup_ca(cgroup);
178 for_each_present_cpu(i) {
179 percpu = cpuacct_cpuusage_read(ca, i);
180 seq_printf(m, "%llu ", (unsigned long long) percpu);
186 static const char * const cpuacct_stat_desc[] = {
187 [CPUACCT_STAT_USER] = "user",
188 [CPUACCT_STAT_SYSTEM] = "system",
191 static int cpuacct_stats_show(struct cgroup *cgrp, struct cftype *cft,
192 struct cgroup_map_cb *cb)
194 struct cpuacct *ca = cgroup_ca(cgrp);
198 for_each_online_cpu(cpu) {
199 struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu);
200 val += kcpustat->cpustat[CPUTIME_USER];
201 val += kcpustat->cpustat[CPUTIME_NICE];
203 val = cputime64_to_clock_t(val);
204 cb->fill(cb, cpuacct_stat_desc[CPUACCT_STAT_USER], val);
207 for_each_online_cpu(cpu) {
208 struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu);
209 val += kcpustat->cpustat[CPUTIME_SYSTEM];
210 val += kcpustat->cpustat[CPUTIME_IRQ];
211 val += kcpustat->cpustat[CPUTIME_SOFTIRQ];
214 val = cputime64_to_clock_t(val);
215 cb->fill(cb, cpuacct_stat_desc[CPUACCT_STAT_SYSTEM], val);
220 static struct cftype files[] = {
223 .read_u64 = cpuusage_read,
224 .write_u64 = cpuusage_write,
227 .name = "usage_percpu",
228 .read_seq_string = cpuacct_percpu_seq_read,
232 .read_map = cpuacct_stats_show,
238 * charge this task's execution time to its accounting group.
240 * called with rq->lock held.
242 void cpuacct_charge(struct task_struct *tsk, u64 cputime)
247 if (unlikely(!cpuacct_subsys.active))
257 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
258 *cpuusage += cputime;
269 * Add user/system time to cpuacct.
271 * Note: it's the caller that updates the account of the root cgroup.
273 void cpuacct_account_field(struct task_struct *p, int index, u64 val)
275 struct kernel_cpustat *kcpustat;
278 if (unlikely(!cpuacct_subsys.active))
283 while (ca != &root_cpuacct) {
284 kcpustat = this_cpu_ptr(ca->cpustat);
285 kcpustat->cpustat[index] += val;
286 ca = __parent_ca(ca);
291 void __init cpuacct_init(void)
293 root_cpuacct.cpustat = &kernel_cpustat;
294 root_cpuacct.cpuusage = &root_cpuacct_cpuusage;
297 struct cgroup_subsys cpuacct_subsys = {
299 .css_alloc = cpuacct_css_alloc,
300 .css_free = cpuacct_css_free,
301 .subsys_id = cpuacct_subsys_id,
302 .base_cftypes = files,