kernel/sched/cpuacct.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0

 /*
  * CPU accounting code for task groups.
  *
  * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
  * (balbir@in.ibm.com).
  */

 /* 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,
 };
	// SPDX-License-Identifier: GPL-2.0

	/*
	* CPU accounting code for task groups.
	*
	* Based on the work by Paul Menage (menage@google.com) and Balbir Singh
	* (balbir@in.ibm.com).
	*/

	/* 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,
	};