// SPDX-License-Identifier: GPL-2.0
/*
* CPU accounting code for task groups.
*
* Based on the work by Paul Menage ([email protected]) and Balbir Singh
* ([email protected]).
*/
/* Time spent by the tasks of the CPU accounting group executing in ... */
enum cpuacct_stat_index {
CPUACCT_STAT_USER, /* ... user mode */
CPUACCT_STAT_SYSTEM, /* ... kernel mode */
CPUACCT_STAT_NSTATS,
};
static const char * const cpuacct_stat_desc[] = {
[CPUACCT_STAT_USER] = "user",
[CPUACCT_STAT_SYSTEM] = "system",
};
/* track CPU usage of a group of tasks and its child groups */
struct cpuacct {
struct cgroup_subsys_state css;
/* cpuusage holds pointer to a u64-type object on every CPU */
u64 __percpu *cpuusage;
struct kernel_cpustat __percpu *cpustat;
};
static inline struct cpuacct *css_ca(struct cgroup_subsys_state *css)
{
return css ? container_of(css, struct cpuacct, css) : NULL;
}
/* Return CPU accounting group to which this task belongs */
static inline struct cpuacct *task_ca(struct task_struct *tsk)
{
return css_ca(task_css(tsk, cpuacct_cgrp_id));
}
static inline struct cpuacct *parent_ca(struct cpuacct *ca)
{
return css_ca(ca->css.parent);
}
static DEFINE_PER_CPU(u64, root_cpuacct_cpuusage);
static struct cpuacct root_cpuacct = {
.cpustat = &kernel_cpustat,
.cpuusage = &root_cpuacct_cpuusage,
};
/* Create a new CPU accounting group */
static struct cgroup_subsys_state *
cpuacct_css_alloc(struct cgroup_subsys_state *parent_css)
{
struct cpuacct *ca;
if (!parent_css)
return &root_cpuacct.css;
ca = kzalloc(sizeof(*ca), GFP_KERNEL);
if (!ca)
goto out;
ca->cpuusage = alloc_percpu(u64);
if (!ca->cpuusage)
goto out_free_ca;
ca->cpustat = alloc_percpu(struct kernel_cpustat);
if (!ca->cpustat)
goto out_free_cpuusage;
return &ca->css;
out_free_cpuusage:
free_percpu(ca->cpuusage);
out_free_ca:
kfree(ca);
out:
return ERR_PTR(-ENOMEM);
}
/* Destroy an existing CPU accounting group */
static void cpuacct_css_free(struct cgroup_subsys_state *css)
{
struct cpuacct *ca = css_ca(css);
free_percpu(ca->cpustat);
free_percpu(ca->cpuusage);
kfree(ca);
}
static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu,
enum cpuacct_stat_index index)
{
u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat;
u64 data;
/*
* We allow index == CPUACCT_STAT_NSTATS here to read
* the sum of usages.
*/
if (WARN_ON_ONCE(index > CPUACCT_STAT_NSTATS))
return 0;
#ifndef CONFIG_64BIT
/*
* Take rq->lock to make 64-bit read safe on 32-bit platforms.
*/
raw_spin_rq_lock_irq(cpu_rq(cpu));
#endif
switch (index) {
case CPUACCT_STAT_USER:
data = cpustat[CPUTIME_USER] + cpustat[CPUTIME_NICE];
break;
case CPUACCT_STAT_SYSTEM:
data = cpustat[CPUTIME_SYSTEM] + cpustat[CPUTIME_IRQ] +
cpustat[CPUTIME_SOFTIRQ];
break;
case CPUACCT_STAT_NSTATS:
data = *cpuusage;
break;
}
#ifndef CONFIG_64BIT
raw_spin_rq_unlock_irq(cpu_rq(cpu));
#endif
return data;
}
static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu)
{
u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat;
/* Don't allow to reset global kernel_cpustat */
if (ca == &root_cpuacct)
return;
#ifndef CONFIG_64BIT
/*
* Take rq->lock to make 64-bit write safe on 32-bit platforms.
*/
raw_spin_rq_lock_irq(cpu_rq(cpu));
#endif
*cpuusage = 0;
cpustat[CPUTIME_USER] = cpustat[CPUTIME_NICE] = 0;
cpustat[CPUTIME_SYSTEM] = cpustat[CPUTIME_IRQ] = 0;
cpustat[CPUTIME_SOFTIRQ] = 0;
#ifndef CONFIG_64BIT
raw_spin_rq_unlock_irq(cpu_rq(cpu));
#endif
}
/* Return total CPU usage (in nanoseconds) of a group */
static u64 __cpuusage_read(struct cgroup_subsys_state *css,
enum cpuacct_stat_index index)
{
struct cpuacct *ca = css_ca(css);
u64 totalcpuusage = 0;
int i;
for_each_possible_cpu(i)
totalcpuusage += cpuacct_cpuusage_read(ca, i, index);
return totalcpuusage;
}
static u64 cpuusage_user_read(struct cgroup_subsys_state *css,
struct cftype *cft)
{
return __cpuusage_read(css, CPUACCT_STAT_USER);
}
static u64 cpuusage_sys_read(struct cgroup_subsys_state *css,
struct cftype *cft)
{
return __cpuusage_read(css, CPUACCT_STAT_SYSTEM);
}
static u64 cpuusage_read(struct cgroup_subsys_state *css, struct cftype *cft)
{
return __cpuusage_read(css, CPUACCT_STAT_NSTATS);
}
static int cpuusage_write(struct cgroup_subsys_state *css, struct cftype *cft,
u64 val)
{
struct cpuacct *ca = css_ca(css);
int cpu;
/*
* Only allow '0' here to do a reset.
*/
if (val)
return -EINVAL;
for_each_possible_cpu(cpu)
cpuacct_cpuusage_write(ca, cpu);
return 0;
}
static int __cpuacct_percpu_seq_show(struct seq_file *m,
enum cpuacct_stat_index index)
{
struct cpuacct *ca = css_ca(seq_css(m));
u64 percpu;
int i;
for_each_possible_cpu(i) {
percpu = cpuacct_cpuusage_read(ca, i, index);
seq_printf(m, "%llu ", (unsigned long long) percpu);
}
seq_printf(m, "\n");
return 0;
}
static int cpuacct_percpu_user_seq_show(struct seq_file *m, void *V)
{
return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_USER);
}
static int cpuacct_percpu_sys_seq_show(struct seq_file *m, void *V)
{
return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_SYSTEM);
}
static int cpuacct_percpu_seq_show(struct seq_file *m, void *V)
{
return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_NSTATS);
}
static int cpuacct_all_seq_show(struct seq_file *m, void *V)
{
struct cpuacct *ca = css_ca(seq_css(m));
int index;
int cpu;
seq_puts(m, "cpu");
for (index = 0; index < CPUACCT_STAT_NSTATS; index++)
seq_printf(m, " %s", cpuacct_stat_desc[index]);
seq_puts(m, "\n");
for_each_possible_cpu(cpu) {
seq_printf(m, "%d", cpu);
for (index = 0; index < CPUACCT_STAT_NSTATS; index++)
seq_printf(m, " %llu",
cpuacct_cpuusage_read(ca, cpu, index));
seq_puts(m, "\n");
}
return 0;
}
static int cpuacct_stats_show(struct seq_file *sf, void *v)
{
struct cpuacct *ca = css_ca(seq_css(sf));
struct task_cputime cputime;
u64 val[CPUACCT_STAT_NSTATS];
int cpu;
int stat;
memset(&cputime, 0, sizeof(cputime));
for_each_possible_cpu(cpu) {
u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat;
cputime.utime += cpustat[CPUTIME_USER];
cputime.utime += cpustat[CPUTIME_NICE];
cputime.stime += cpustat[CPUTIME_SYSTEM];
cputime.stime += cpustat[CPUTIME_IRQ];
cputime.stime += cpustat[CPUTIME_SOFTIRQ];
cputime.sum_exec_runtime += *per_cpu_ptr(ca->cpuusage, cpu);
}
cputime_adjust(&cputime, &seq_css(sf)->cgroup->prev_cputime,
&val[CPUACCT_STAT_USER], &val[CPUACCT_STAT_SYSTEM]);
for (stat = 0; stat < CPUACCT_STAT_NSTATS; stat++) {
seq_printf(sf, "%s %llu\n", cpuacct_stat_desc[stat],
nsec_to_clock_t(val[stat]));
}
return 0;
}
static struct cftype files[] = {
{
.name = "usage",
.read_u64 = cpuusage_read,
.write_u64 = cpuusage_write,
},
{
.name = "usage_user",
.read_u64 = cpuusage_user_read,
},
{
.name = "usage_sys",
.read_u64 = cpuusage_sys_read,
},
{
.name = "usage_percpu",
.seq_show = cpuacct_percpu_seq_show,
},
{
.name = "usage_percpu_user",
.seq_show = cpuacct_percpu_user_seq_show,
},
{
.name = "usage_percpu_sys",
.seq_show = cpuacct_percpu_sys_seq_show,
},
{
.name = "usage_all",
.seq_show = cpuacct_all_seq_show,
},
{
.name = "stat",
.seq_show = cpuacct_stats_show,
},
{ } /* terminate */
};
/*
* charge this task's execution time to its accounting group.
*
* called with rq->lock held.
*/
void cpuacct_charge(struct task_struct *tsk, u64 cputime)
{
unsigned int cpu = task_cpu(tsk);
struct cpuacct *ca;
lockdep_assert_rq_held(cpu_rq(cpu));
for (ca = task_ca(tsk); ca; ca = parent_ca(ca))
*per_cpu_ptr(ca->cpuusage, cpu) += cputime;
}
/*
* Add user/system time to cpuacct.
*
* Note: it's the caller that updates the account of the root cgroup.
*/
void cpuacct_account_field(struct task_struct *tsk, int index, u64 val)
{
struct cpuacct *ca;
for (ca = task_ca(tsk); ca != &root_cpuacct; ca = parent_ca(ca))
__this_cpu_add(ca->cpustat->cpustat[index], val);
}
struct cgroup_subsys cpuacct_cgrp_subsys = {
.css_alloc = cpuacct_css_alloc,
.css_free = cpuacct_css_free,
.legacy_cftypes = files,
.early_init = true,
};
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