1 files changed, 363 insertions, 0 deletions
diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c
new file mode 100644
index 000000000..0de9dda09
--- /dev/null
+++ b/kernel/sched/cpuacct.c
@@ -0,0 +1,363 @@
+// 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,
+};