Commit 62d0df64 authored by Paul Menage's avatar Paul Menage Committed by Linus Torvalds

Task Control Groups: example CPU accounting subsystem

This example demonstrates how to use the generic cgroup subsystem for a
simple resource tracker that counts, for the processes in a cgroup, the
total CPU time used and the %CPU used in the last complete 10 second interval.

Portions contributed by Balbir Singh <balbir@in.ibm.com>
Signed-off-by: default avatarPaul Menage <menage@google.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8793d854
......@@ -13,4 +13,10 @@ SUBSYS(cpuset)
/* */
#ifdef CONFIG_CGROUP_CPUACCT
SUBSYS(cpuacct)
#endif
/* */
/* */
#ifndef _LINUX_CPU_ACCT_H
#define _LINUX_CPU_ACCT_H
#include <linux/cgroup.h>
#include <asm/cputime.h>
#ifdef CONFIG_CGROUP_CPUACCT
extern void cpuacct_charge(struct task_struct *, cputime_t cputime);
#else
static void inline cpuacct_charge(struct task_struct *p, cputime_t cputime) {}
#endif
#endif
......@@ -335,6 +335,13 @@ config PROC_PID_CPUSET
depends on CPUSETS
default y
config CGROUP_CPUACCT
bool "Simple CPU accounting cgroup subsystem"
depends on CGROUPS
help
Provides a simple Resource Controller for monitoring the
total CPU consumed by the tasks in a cgroup
config RELAY
bool "Kernel->user space relay support (formerly relayfs)"
help
......
......@@ -38,6 +38,7 @@ obj-$(CONFIG_KEXEC) += kexec.o
obj-$(CONFIG_COMPAT) += compat.o
obj-$(CONFIG_CGROUPS) += cgroup.o
obj-$(CONFIG_CPUSETS) += cpuset.o
obj-$(CONFIG_CGROUP_CPUACCT) += cpu_acct.o
obj-$(CONFIG_IKCONFIG) += configs.o
obj-$(CONFIG_STOP_MACHINE) += stop_machine.o
obj-$(CONFIG_AUDIT) += audit.o auditfilter.o
......
/*
* kernel/cpu_acct.c - CPU accounting cgroup subsystem
*
* Copyright (C) Google Inc, 2006
*
* Developed by Paul Menage (menage@google.com) and Balbir Singh
* (balbir@in.ibm.com)
*
*/
/*
* Example cgroup subsystem for reporting total CPU usage of tasks in a
* cgroup, along with percentage load over a time interval
*/
#include <linux/module.h>
#include <linux/cgroup.h>
#include <linux/fs.h>
#include <linux/rcupdate.h>
#include <asm/div64.h>
struct cpuacct {
struct cgroup_subsys_state css;
spinlock_t lock;
/* total time used by this class */
cputime64_t time;
/* time when next load calculation occurs */
u64 next_interval_check;
/* time used in current period */
cputime64_t current_interval_time;
/* time used in last period */
cputime64_t last_interval_time;
};
struct cgroup_subsys cpuacct_subsys;
static inline struct cpuacct *cgroup_ca(struct cgroup *cont)
{
return container_of(cgroup_subsys_state(cont, cpuacct_subsys_id),
struct cpuacct, css);
}
static inline struct cpuacct *task_ca(struct task_struct *task)
{
return container_of(task_subsys_state(task, cpuacct_subsys_id),
struct cpuacct, css);
}
#define INTERVAL (HZ * 10)
static inline u64 next_interval_boundary(u64 now)
{
/* calculate the next interval boundary beyond the
* current time */
do_div(now, INTERVAL);
return (now + 1) * INTERVAL;
}
static struct cgroup_subsys_state *cpuacct_create(
struct cgroup_subsys *ss, struct cgroup *cont)
{
struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
if (!ca)
return ERR_PTR(-ENOMEM);
spin_lock_init(&ca->lock);
ca->next_interval_check = next_interval_boundary(get_jiffies_64());
return &ca->css;
}
static void cpuacct_destroy(struct cgroup_subsys *ss,
struct cgroup *cont)
{
kfree(cgroup_ca(cont));
}
/* Lazily update the load calculation if necessary. Called with ca locked */
static void cpuusage_update(struct cpuacct *ca)
{
u64 now = get_jiffies_64();
/* If we're not due for an update, return */
if (ca->next_interval_check > now)
return;
if (ca->next_interval_check <= (now - INTERVAL)) {
/* If it's been more than an interval since the last
* check, then catch up - the last interval must have
* been zero load */
ca->last_interval_time = 0;
ca->next_interval_check = next_interval_boundary(now);
} else {
/* If a steal takes the last interval time negative,
* then we just ignore it */
if ((s64)ca->current_interval_time > 0)
ca->last_interval_time = ca->current_interval_time;
else
ca->last_interval_time = 0;
ca->next_interval_check += INTERVAL;
}
ca->current_interval_time = 0;
}
static u64 cpuusage_read(struct cgroup *cont, struct cftype *cft)
{
struct cpuacct *ca = cgroup_ca(cont);
u64 time;
spin_lock_irq(&ca->lock);
cpuusage_update(ca);
time = cputime64_to_jiffies64(ca->time);
spin_unlock_irq(&ca->lock);
/* Convert 64-bit jiffies to seconds */
time *= 1000;
do_div(time, HZ);
return time;
}
static u64 load_read(struct cgroup *cont, struct cftype *cft)
{
struct cpuacct *ca = cgroup_ca(cont);
u64 time;
/* Find the time used in the previous interval */
spin_lock_irq(&ca->lock);
cpuusage_update(ca);
time = cputime64_to_jiffies64(ca->last_interval_time);
spin_unlock_irq(&ca->lock);
/* Convert time to a percentage, to give the load in the
* previous period */
time *= 100;
do_div(time, INTERVAL);
return time;
}
static struct cftype files[] = {
{
.name = "usage",
.read_uint = cpuusage_read,
},
{
.name = "load",
.read_uint = load_read,
}
};
static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cont)
{
return cgroup_add_files(cont, ss, files, ARRAY_SIZE(files));
}
void cpuacct_charge(struct task_struct *task, cputime_t cputime)
{
struct cpuacct *ca;
unsigned long flags;
if (!cpuacct_subsys.active)
return;
rcu_read_lock();
ca = task_ca(task);
if (ca) {
spin_lock_irqsave(&ca->lock, flags);
cpuusage_update(ca);
ca->time = cputime64_add(ca->time, cputime);
ca->current_interval_time =
cputime64_add(ca->current_interval_time, cputime);
spin_unlock_irqrestore(&ca->lock, flags);
}
rcu_read_unlock();
}
struct cgroup_subsys cpuacct_subsys = {
.name = "cpuacct",
.create = cpuacct_create,
.destroy = cpuacct_destroy,
.populate = cpuacct_populate,
.subsys_id = cpuacct_subsys_id,
};
......@@ -51,6 +51,7 @@
#include <linux/cpu.h>
#include <linux/cpuset.h>
#include <linux/percpu.h>
#include <linux/cpu_acct.h>
#include <linux/kthread.h>
#include <linux/seq_file.h>
#include <linux/sysctl.h>
......@@ -3307,9 +3308,13 @@ void account_user_time(struct task_struct *p, cputime_t cputime)
{
struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
cputime64_t tmp;
struct rq *rq = this_rq();
p->utime = cputime_add(p->utime, cputime);
if (p != rq->idle)
cpuacct_charge(p, cputime);
/* Add user time to cpustat. */
tmp = cputime_to_cputime64(cputime);
if (TASK_NICE(p) > 0)
......@@ -3374,9 +3379,10 @@ void account_system_time(struct task_struct *p, int hardirq_offset,
cpustat->irq = cputime64_add(cpustat->irq, tmp);
else if (softirq_count())
cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
else if (p != rq->idle)
else if (p != rq->idle) {
cpustat->system = cputime64_add(cpustat->system, tmp);
else if (atomic_read(&rq->nr_iowait) > 0)
cpuacct_charge(p, cputime);
} else if (atomic_read(&rq->nr_iowait) > 0)
cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
else
cpustat->idle = cputime64_add(cpustat->idle, tmp);
......@@ -3412,8 +3418,10 @@ void account_steal_time(struct task_struct *p, cputime_t steal)
cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
else
cpustat->idle = cputime64_add(cpustat->idle, tmp);
} else
} else {
cpustat->steal = cputime64_add(cpustat->steal, tmp);
cpuacct_charge(p, -tmp);
}
}
/*
......
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