xref: /linux/kernel/sched/debug.c (revision 2ab99ad7faef1f0a4529e8bae92009fa56242bd4)

// SPDX-License-Identifier: GPL-2.0-only
/*
 * kernel/sched/debug.c
 *
 * Print the CFS rbtree and other debugging details
 *
 * Copyright(C) 2007, Red Hat, Inc., Ingo Molnar
 */
#include <linux/debugfs.h>
#include <linux/nmi.h>
#include "sched.h"

/*
 * This allows printing both to /sys/kernel/debug/sched/debug and
 * to the console
 */
#define SEQ_printf(m, x...)			\
 do {						\
	if (m)					\
		seq_printf(m, x);		\
	else					\
		pr_cont(x);			\
 } while (0)

/*
 * Ease the printing of nsec fields:
 */
static long long nsec_high(unsigned long long nsec)
{
	if ((long long)nsec < 0) {
		nsec = -nsec;
		do_div(nsec, 1000000);
		return -nsec;
	}
	do_div(nsec, 1000000);

	return nsec;
}

static unsigned long nsec_low(unsigned long long nsec)
{
	if ((long long)nsec < 0)
		nsec = -nsec;

	return do_div(nsec, 1000000);
}

#define SPLIT_NS(x) nsec_high(x), nsec_low(x)

#define SCHED_FEAT(name, enabled)	\
	#name ,

static const char * const sched_feat_names[] = {
#include "features.h"
};

#undef SCHED_FEAT

static int sched_feat_show(struct seq_file *m, void *v)
{
	int i;

	for (i = 0; i < __SCHED_FEAT_NR; i++) {
		if (!(sysctl_sched_features & (1UL << i)))
			seq_puts(m, "NO_");
		seq_printf(m, "%s ", sched_feat_names[i]);
	}
	seq_puts(m, "\n");

	return 0;
}

#ifdef CONFIG_JUMP_LABEL

#define jump_label_key__true  STATIC_KEY_INIT_TRUE
#define jump_label_key__false STATIC_KEY_INIT_FALSE

#define SCHED_FEAT(name, enabled)	\
	jump_label_key__##enabled ,

struct static_key sched_feat_keys[__SCHED_FEAT_NR] = {
#include "features.h"
};

#undef SCHED_FEAT

static void sched_feat_disable(int i)
{
	static_key_disable_cpuslocked(&sched_feat_keys[i]);
}

static void sched_feat_enable(int i)
{
	static_key_enable_cpuslocked(&sched_feat_keys[i]);
}
#else /* !CONFIG_JUMP_LABEL: */
static void sched_feat_disable(int i) { };
static void sched_feat_enable(int i) { };
#endif /* !CONFIG_JUMP_LABEL */

static int sched_feat_set(char *cmp)
{
	int i;
	int neg = 0;

	if (strncmp(cmp, "NO_", 3) == 0) {
		neg = 1;
		cmp += 3;
	}

	i = match_string(sched_feat_names, __SCHED_FEAT_NR, cmp);
	if (i < 0)
		return i;

	if (neg) {
		sysctl_sched_features &= ~(1UL << i);
		sched_feat_disable(i);
	} else {
		sysctl_sched_features |= (1UL << i);
		sched_feat_enable(i);
	}

	return 0;
}

static ssize_t
sched_feat_write(struct file *filp, const char __user *ubuf,
		size_t cnt, loff_t *ppos)
{
	char buf[64];
	char *cmp;
	int ret;
	struct inode *inode;

	if (cnt > 63)
		cnt = 63;

	if (copy_from_user(&buf, ubuf, cnt))
		return -EFAULT;

	buf[cnt] = 0;
	cmp = strstrip(buf);

	/* Ensure the static_key remains in a consistent state */
	inode = file_inode(filp);
	cpus_read_lock();
	inode_lock(inode);
	ret = sched_feat_set(cmp);
	inode_unlock(inode);
	cpus_read_unlock();
	if (ret < 0)
		return ret;

	*ppos += cnt;

	return cnt;
}

static int sched_feat_open(struct inode *inode, struct file *filp)
{
	return single_open(filp, sched_feat_show, NULL);
}

static const struct file_operations sched_feat_fops = {
	.open		= sched_feat_open,
	.write		= sched_feat_write,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

static ssize_t sched_scaling_write(struct file *filp, const char __user *ubuf,
				   size_t cnt, loff_t *ppos)
{
	unsigned int scaling;
	int ret;

	ret = kstrtouint_from_user(ubuf, cnt, 10, &scaling);
	if (ret)
		return ret;

	if (scaling >= SCHED_TUNABLESCALING_END)
		return -EINVAL;

	sysctl_sched_tunable_scaling = scaling;
	if (sched_update_scaling())
		return -EINVAL;

	*ppos += cnt;
	return cnt;
}

static int sched_scaling_show(struct seq_file *m, void *v)
{
	seq_printf(m, "%d\n", sysctl_sched_tunable_scaling);
	return 0;
}

static int sched_scaling_open(struct inode *inode, struct file *filp)
{
	return single_open(filp, sched_scaling_show, NULL);
}

static const struct file_operations sched_scaling_fops = {
	.open		= sched_scaling_open,
	.write		= sched_scaling_write,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

#ifdef CONFIG_PREEMPT_DYNAMIC

static ssize_t sched_dynamic_write(struct file *filp, const char __user *ubuf,
				   size_t cnt, loff_t *ppos)
{
	char buf[16];
	int mode;

	if (cnt > 15)
		cnt = 15;

	if (copy_from_user(&buf, ubuf, cnt))
		return -EFAULT;

	buf[cnt] = 0;
	mode = sched_dynamic_mode(strstrip(buf));
	if (mode < 0)
		return mode;

	sched_dynamic_update(mode);

	*ppos += cnt;

	return cnt;
}

static int sched_dynamic_show(struct seq_file *m, void *v)
{
	int i = (IS_ENABLED(CONFIG_PREEMPT_RT) || IS_ENABLED(CONFIG_ARCH_HAS_PREEMPT_LAZY)) * 2;
	int j;

	/* Count entries in NULL terminated preempt_modes */
	for (j = 0; preempt_modes[j]; j++)
		;
	j -= !IS_ENABLED(CONFIG_ARCH_HAS_PREEMPT_LAZY);

	for (; i < j; i++) {
		if (preempt_dynamic_mode == i)
			seq_puts(m, "(");
		seq_puts(m, preempt_modes[i]);
		if (preempt_dynamic_mode == i)
			seq_puts(m, ")");

		seq_puts(m, " ");
	}

	seq_puts(m, "\n");
	return 0;
}

static int sched_dynamic_open(struct inode *inode, struct file *filp)
{
	return single_open(filp, sched_dynamic_show, NULL);
}

static const struct file_operations sched_dynamic_fops = {
	.open		= sched_dynamic_open,
	.write		= sched_dynamic_write,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

#endif /* CONFIG_PREEMPT_DYNAMIC */

__read_mostly bool sched_debug_verbose;

static struct dentry           *sd_dentry;


static ssize_t sched_verbose_write(struct file *filp, const char __user *ubuf,
				  size_t cnt, loff_t *ppos)
{
	ssize_t result;
	bool orig;

	cpus_read_lock();
	sched_domains_mutex_lock();

	orig = sched_debug_verbose;
	result = debugfs_write_file_bool(filp, ubuf, cnt, ppos);

	if (sched_debug_verbose && !orig)
		update_sched_domain_debugfs();
	else if (!sched_debug_verbose && orig) {
		debugfs_remove(sd_dentry);
		sd_dentry = NULL;
	}

	sched_domains_mutex_unlock();
	cpus_read_unlock();

	return result;
}

static const struct file_operations sched_verbose_fops = {
	.read =         debugfs_read_file_bool,
	.write =        sched_verbose_write,
	.open =         simple_open,
	.llseek =       default_llseek,
};

static const struct seq_operations sched_debug_sops;

static int sched_debug_open(struct inode *inode, struct file *filp)
{
	return seq_open(filp, &sched_debug_sops);
}

static const struct file_operations sched_debug_fops = {
	.open		= sched_debug_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};

enum dl_param {
	DL_RUNTIME = 0,
	DL_PERIOD,
};

static unsigned long dl_server_period_max = (1UL << 22) * NSEC_PER_USEC; /* ~4 seconds */
static unsigned long dl_server_period_min = (100) * NSEC_PER_USEC;     /* 100 us */

static ssize_t sched_server_write_common(struct file *filp, const char __user *ubuf,
					 size_t cnt, loff_t *ppos, enum dl_param param,
					 void *server)
{
	long cpu = (long) ((struct seq_file *) filp->private_data)->private;
	struct sched_dl_entity *dl_se = (struct sched_dl_entity *)server;
	u64 old_runtime, runtime, period;
	struct rq *rq = cpu_rq(cpu);
	int retval = 0;
	size_t err;
	u64 value;

	err = kstrtoull_from_user(ubuf, cnt, 10, &value);
	if (err)
		return err;

	scoped_guard (rq_lock_irqsave, rq) {
		old_runtime = runtime = dl_se->dl_runtime;
		period = dl_se->dl_period;

		switch (param) {
		case DL_RUNTIME:
			if (runtime == value)
				break;
			runtime = value;
			break;
		case DL_PERIOD:
			if (value == period)
				break;
			period = value;
			break;
		}

		if (runtime > period ||
		    period > dl_server_period_max ||
		    period < dl_server_period_min) {
			return  -EINVAL;
		}

		update_rq_clock(rq);
		dl_server_stop(dl_se);
		retval = dl_server_apply_params(dl_se, runtime, period, 0);
		dl_server_start(dl_se);

		if (retval < 0)
			return retval;
	}

	if (!!old_runtime ^ !!runtime) {
		pr_info("%s server %sabled on CPU %d%s.\n",
			server == &rq->fair_server ? "Fair" : "Ext",
			runtime ? "en" : "dis",
			cpu_of(rq),
			runtime ? "" : ", system may malfunction due to starvation");
	}

	*ppos += cnt;
	return cnt;
}

static size_t sched_server_show_common(struct seq_file *m, void *v, enum dl_param param,
				       void *server)
{
	struct sched_dl_entity *dl_se = (struct sched_dl_entity *)server;
	u64 value;

	switch (param) {
	case DL_RUNTIME:
		value = dl_se->dl_runtime;
		break;
	case DL_PERIOD:
		value = dl_se->dl_period;
		break;
	}

	seq_printf(m, "%llu\n", value);
	return 0;
}

static ssize_t
sched_fair_server_runtime_write(struct file *filp, const char __user *ubuf,
				size_t cnt, loff_t *ppos)
{
	long cpu = (long) ((struct seq_file *) filp->private_data)->private;
	struct rq *rq = cpu_rq(cpu);

	return sched_server_write_common(filp, ubuf, cnt, ppos, DL_RUNTIME,
					&rq->fair_server);
}

static int sched_fair_server_runtime_show(struct seq_file *m, void *v)
{
	unsigned long cpu = (unsigned long) m->private;
	struct rq *rq = cpu_rq(cpu);

	return sched_server_show_common(m, v, DL_RUNTIME, &rq->fair_server);
}

static int sched_fair_server_runtime_open(struct inode *inode, struct file *filp)
{
	return single_open(filp, sched_fair_server_runtime_show, inode->i_private);
}

static const struct file_operations fair_server_runtime_fops = {
	.open		= sched_fair_server_runtime_open,
	.write		= sched_fair_server_runtime_write,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

#ifdef CONFIG_SCHED_CLASS_EXT
static ssize_t
sched_ext_server_runtime_write(struct file *filp, const char __user *ubuf,
			       size_t cnt, loff_t *ppos)
{
	long cpu = (long) ((struct seq_file *) filp->private_data)->private;
	struct rq *rq = cpu_rq(cpu);

	return sched_server_write_common(filp, ubuf, cnt, ppos, DL_RUNTIME,
					&rq->ext_server);
}

static int sched_ext_server_runtime_show(struct seq_file *m, void *v)
{
	unsigned long cpu = (unsigned long) m->private;
	struct rq *rq = cpu_rq(cpu);

	return sched_server_show_common(m, v, DL_RUNTIME, &rq->ext_server);
}

static int sched_ext_server_runtime_open(struct inode *inode, struct file *filp)
{
	return single_open(filp, sched_ext_server_runtime_show, inode->i_private);
}

static const struct file_operations ext_server_runtime_fops = {
	.open		= sched_ext_server_runtime_open,
	.write		= sched_ext_server_runtime_write,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};
#endif /* CONFIG_SCHED_CLASS_EXT */

static ssize_t
sched_fair_server_period_write(struct file *filp, const char __user *ubuf,
			       size_t cnt, loff_t *ppos)
{
	long cpu = (long) ((struct seq_file *) filp->private_data)->private;
	struct rq *rq = cpu_rq(cpu);

	return sched_server_write_common(filp, ubuf, cnt, ppos, DL_PERIOD,
					&rq->fair_server);
}

static int sched_fair_server_period_show(struct seq_file *m, void *v)
{
	unsigned long cpu = (unsigned long) m->private;
	struct rq *rq = cpu_rq(cpu);

	return sched_server_show_common(m, v, DL_PERIOD, &rq->fair_server);
}

static int sched_fair_server_period_open(struct inode *inode, struct file *filp)
{
	return single_open(filp, sched_fair_server_period_show, inode->i_private);
}

static const struct file_operations fair_server_period_fops = {
	.open		= sched_fair_server_period_open,
	.write		= sched_fair_server_period_write,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

#ifdef CONFIG_SCHED_CLASS_EXT
static ssize_t
sched_ext_server_period_write(struct file *filp, const char __user *ubuf,
			      size_t cnt, loff_t *ppos)
{
	long cpu = (long) ((struct seq_file *) filp->private_data)->private;
	struct rq *rq = cpu_rq(cpu);

	return sched_server_write_common(filp, ubuf, cnt, ppos, DL_PERIOD,
					&rq->ext_server);
}

static int sched_ext_server_period_show(struct seq_file *m, void *v)
{
	unsigned long cpu = (unsigned long) m->private;
	struct rq *rq = cpu_rq(cpu);

	return sched_server_show_common(m, v, DL_PERIOD, &rq->ext_server);
}

static int sched_ext_server_period_open(struct inode *inode, struct file *filp)
{
	return single_open(filp, sched_ext_server_period_show, inode->i_private);
}

static const struct file_operations ext_server_period_fops = {
	.open		= sched_ext_server_period_open,
	.write		= sched_ext_server_period_write,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};
#endif /* CONFIG_SCHED_CLASS_EXT */

static struct dentry *debugfs_sched;

static void debugfs_fair_server_init(void)
{
	struct dentry *d_fair;
	unsigned long cpu;

	d_fair = debugfs_create_dir("fair_server", debugfs_sched);
	if (!d_fair)
		return;

	for_each_possible_cpu(cpu) {
		struct dentry *d_cpu;
		char buf[32];

		snprintf(buf, sizeof(buf), "cpu%lu", cpu);
		d_cpu = debugfs_create_dir(buf, d_fair);

		debugfs_create_file("runtime", 0644, d_cpu, (void *) cpu, &fair_server_runtime_fops);
		debugfs_create_file("period", 0644, d_cpu, (void *) cpu, &fair_server_period_fops);
	}
}

#ifdef CONFIG_SCHED_CLASS_EXT
static void debugfs_ext_server_init(void)
{
	struct dentry *d_ext;
	unsigned long cpu;

	d_ext = debugfs_create_dir("ext_server", debugfs_sched);
	if (!d_ext)
		return;

	for_each_possible_cpu(cpu) {
		struct dentry *d_cpu;
		char buf[32];

		snprintf(buf, sizeof(buf), "cpu%lu", cpu);
		d_cpu = debugfs_create_dir(buf, d_ext);

		debugfs_create_file("runtime", 0644, d_cpu, (void *) cpu, &ext_server_runtime_fops);
		debugfs_create_file("period", 0644, d_cpu, (void *) cpu, &ext_server_period_fops);
	}
}
#endif /* CONFIG_SCHED_CLASS_EXT */

static __init int sched_init_debug(void)
{
	struct dentry __maybe_unused *numa;

	debugfs_sched = debugfs_create_dir("sched", NULL);

	debugfs_create_file("features", 0644, debugfs_sched, NULL, &sched_feat_fops);
	debugfs_create_file_unsafe("verbose", 0644, debugfs_sched, &sched_debug_verbose, &sched_verbose_fops);
#ifdef CONFIG_PREEMPT_DYNAMIC
	debugfs_create_file("preempt", 0644, debugfs_sched, NULL, &sched_dynamic_fops);
#endif

	debugfs_create_u32("base_slice_ns", 0644, debugfs_sched, &sysctl_sched_base_slice);

	debugfs_create_u32("latency_warn_ms", 0644, debugfs_sched, &sysctl_resched_latency_warn_ms);
	debugfs_create_u32("latency_warn_once", 0644, debugfs_sched, &sysctl_resched_latency_warn_once);

	debugfs_create_file("tunable_scaling", 0644, debugfs_sched, NULL, &sched_scaling_fops);
	debugfs_create_u32("migration_cost_ns", 0644, debugfs_sched, &sysctl_sched_migration_cost);
	debugfs_create_u32("nr_migrate", 0644, debugfs_sched, &sysctl_sched_nr_migrate);

	sched_domains_mutex_lock();
	update_sched_domain_debugfs();
	sched_domains_mutex_unlock();

#ifdef CONFIG_NUMA_BALANCING
	numa = debugfs_create_dir("numa_balancing", debugfs_sched);

	debugfs_create_u32("scan_delay_ms", 0644, numa, &sysctl_numa_balancing_scan_delay);
	debugfs_create_u32("scan_period_min_ms", 0644, numa, &sysctl_numa_balancing_scan_period_min);
	debugfs_create_u32("scan_period_max_ms", 0644, numa, &sysctl_numa_balancing_scan_period_max);
	debugfs_create_u32("scan_size_mb", 0644, numa, &sysctl_numa_balancing_scan_size);
	debugfs_create_u32("hot_threshold_ms", 0644, numa, &sysctl_numa_balancing_hot_threshold);
#endif /* CONFIG_NUMA_BALANCING */

	debugfs_create_file("debug", 0444, debugfs_sched, NULL, &sched_debug_fops);

	debugfs_fair_server_init();
#ifdef CONFIG_SCHED_CLASS_EXT
	debugfs_ext_server_init();
#endif

	return 0;
}
late_initcall(sched_init_debug);

static cpumask_var_t		sd_sysctl_cpus;

static int sd_flags_show(struct seq_file *m, void *v)
{
	unsigned long flags = *(unsigned int *)m->private;
	int idx;

	for_each_set_bit(idx, &flags, __SD_FLAG_CNT) {
		seq_puts(m, sd_flag_debug[idx].name);
		seq_puts(m, " ");
	}
	seq_puts(m, "\n");

	return 0;
}

static int sd_flags_open(struct inode *inode, struct file *file)
{
	return single_open(file, sd_flags_show, inode->i_private);
}

static const struct file_operations sd_flags_fops = {
	.open		= sd_flags_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

static void register_sd(struct sched_domain *sd, struct dentry *parent)
{
#define SDM(type, mode, member)	\
	debugfs_create_##type(#member, mode, parent, &sd->member)

	SDM(ulong, 0644, min_interval);
	SDM(ulong, 0644, max_interval);
	SDM(u64,   0644, max_newidle_lb_cost);
	SDM(u32,   0644, busy_factor);
	SDM(u32,   0644, imbalance_pct);
	SDM(u32,   0644, cache_nice_tries);
	SDM(str,   0444, name);

#undef SDM

	debugfs_create_file("flags", 0444, parent, &sd->flags, &sd_flags_fops);
	debugfs_create_file("groups_flags", 0444, parent, &sd->groups->flags, &sd_flags_fops);
	debugfs_create_u32("level", 0444, parent, (u32 *)&sd->level);

	if (sd->flags & SD_ASYM_PACKING)
		debugfs_create_u32("group_asym_prefer_cpu", 0444, parent,
				   (u32 *)&sd->groups->asym_prefer_cpu);
}

void update_sched_domain_debugfs(void)
{
	int cpu, i;

	/*
	 * This can unfortunately be invoked before sched_debug_init() creates
	 * the debug directory. Don't touch sd_sysctl_cpus until then.
	 */
	if (!debugfs_sched)
		return;

	if (!sched_debug_verbose)
		return;

	if (!cpumask_available(sd_sysctl_cpus)) {
		if (!alloc_cpumask_var(&sd_sysctl_cpus, GFP_KERNEL))
			return;
		cpumask_copy(sd_sysctl_cpus, cpu_possible_mask);
	}

	if (!sd_dentry) {
		sd_dentry = debugfs_create_dir("domains", debugfs_sched);

		/* rebuild sd_sysctl_cpus if empty since it gets cleared below */
		if (cpumask_empty(sd_sysctl_cpus))
			cpumask_copy(sd_sysctl_cpus, cpu_online_mask);
	}

	for_each_cpu(cpu, sd_sysctl_cpus) {
		struct sched_domain *sd;
		struct dentry *d_cpu;
		char buf[32];

		snprintf(buf, sizeof(buf), "cpu%d", cpu);
		debugfs_lookup_and_remove(buf, sd_dentry);
		d_cpu = debugfs_create_dir(buf, sd_dentry);

		i = 0;
		for_each_domain(cpu, sd) {
			struct dentry *d_sd;

			snprintf(buf, sizeof(buf), "domain%d", i);
			d_sd = debugfs_create_dir(buf, d_cpu);

			register_sd(sd, d_sd);
			i++;
		}

		__cpumask_clear_cpu(cpu, sd_sysctl_cpus);
	}
}

void dirty_sched_domain_sysctl(int cpu)
{
	if (cpumask_available(sd_sysctl_cpus))
		__cpumask_set_cpu(cpu, sd_sysctl_cpus);
}

#ifdef CONFIG_FAIR_GROUP_SCHED
static void print_cfs_group_stats(struct seq_file *m, int cpu, struct task_group *tg)
{
	struct sched_entity *se = tg->se[cpu];

#define P(F)		SEQ_printf(m, "  .%-30s: %lld\n",	#F, (long long)F)
#define P_SCHEDSTAT(F)	SEQ_printf(m, "  .%-30s: %lld\n",	\
		#F, (long long)schedstat_val(stats->F))
#define PN(F)		SEQ_printf(m, "  .%-30s: %lld.%06ld\n", #F, SPLIT_NS((long long)F))
#define PN_SCHEDSTAT(F)	SEQ_printf(m, "  .%-30s: %lld.%06ld\n", \
		#F, SPLIT_NS((long long)schedstat_val(stats->F)))

	if (!se)
		return;

	PN(se->exec_start);
	PN(se->vruntime);
	PN(se->sum_exec_runtime);

	if (schedstat_enabled()) {
		struct sched_statistics *stats;
		stats = __schedstats_from_se(se);

		PN_SCHEDSTAT(wait_start);
		PN_SCHEDSTAT(sleep_start);
		PN_SCHEDSTAT(block_start);
		PN_SCHEDSTAT(sleep_max);
		PN_SCHEDSTAT(block_max);
		PN_SCHEDSTAT(exec_max);
		PN_SCHEDSTAT(slice_max);
		PN_SCHEDSTAT(wait_max);
		PN_SCHEDSTAT(wait_sum);
		P_SCHEDSTAT(wait_count);
	}

	P(se->load.weight);
	P(se->avg.load_avg);
	P(se->avg.util_avg);
	P(se->avg.runnable_avg);

#undef PN_SCHEDSTAT
#undef PN
#undef P_SCHEDSTAT
#undef P
}
#endif /* CONFIG_FAIR_GROUP_SCHED */

#ifdef CONFIG_CGROUP_SCHED
static DEFINE_SPINLOCK(sched_debug_lock);
static char group_path[PATH_MAX];

static void task_group_path(struct task_group *tg, char *path, int plen)
{
	if (autogroup_path(tg, path, plen))
		return;

	cgroup_path(tg->css.cgroup, path, plen);
}

/*
 * Only 1 SEQ_printf_task_group_path() caller can use the full length
 * group_path[] for cgroup path. Other simultaneous callers will have
 * to use a shorter stack buffer. A "..." suffix is appended at the end
 * of the stack buffer so that it will show up in case the output length
 * matches the given buffer size to indicate possible path name truncation.
 */
#define SEQ_printf_task_group_path(m, tg, fmt...)			\
{									\
	if (spin_trylock(&sched_debug_lock)) {				\
		task_group_path(tg, group_path, sizeof(group_path));	\
		SEQ_printf(m, fmt, group_path);				\
		spin_unlock(&sched_debug_lock);				\
	} else {							\
		char buf[128];						\
		char *bufend = buf + sizeof(buf) - 3;			\
		task_group_path(tg, buf, bufend - buf);			\
		strcpy(bufend - 1, "...");				\
		SEQ_printf(m, fmt, buf);				\
	}								\
}
#endif

static void
print_task(struct seq_file *m, struct rq *rq, struct task_struct *p)
{
	if (task_current(rq, p))
		SEQ_printf(m, ">R");
	else
		SEQ_printf(m, " %c", task_state_to_char(p));

	SEQ_printf(m, " %15s %5d %9Ld.%06ld   %c   %9Ld.%06ld %c %9Ld.%06ld %9Ld.%06ld %9Ld   %5d ",
		p->comm, task_pid_nr(p),
		SPLIT_NS(p->se.vruntime),
		entity_eligible(cfs_rq_of(&p->se), &p->se) ? 'E' : 'N',
		SPLIT_NS(p->se.deadline),
		p->se.custom_slice ? 'S' : ' ',
		SPLIT_NS(p->se.slice),
		SPLIT_NS(p->se.sum_exec_runtime),
		(long long)(p->nvcsw + p->nivcsw),
		p->prio);

	SEQ_printf(m, "%9lld.%06ld %9lld.%06ld %9lld.%06ld",
		SPLIT_NS(schedstat_val_or_zero(p->stats.wait_sum)),
		SPLIT_NS(schedstat_val_or_zero(p->stats.sum_sleep_runtime)),
		SPLIT_NS(schedstat_val_or_zero(p->stats.sum_block_runtime)));

#ifdef CONFIG_NUMA_BALANCING
	SEQ_printf(m, "   %d      %d", task_node(p), task_numa_group_id(p));
#endif
#ifdef CONFIG_CGROUP_SCHED
	SEQ_printf_task_group_path(m, task_group(p), "        %s")
#endif

	SEQ_printf(m, "\n");
}

static void print_rq(struct seq_file *m, struct rq *rq, int rq_cpu)
{
	struct task_struct *g, *p;

	SEQ_printf(m, "\n");
	SEQ_printf(m, "runnable tasks:\n");
	SEQ_printf(m, " S            task   PID       vruntime   eligible    "
		   "deadline             slice          sum-exec      switches  "
		   "prio         wait-time        sum-sleep       sum-block"
#ifdef CONFIG_NUMA_BALANCING
		   "  node   group-id"
#endif
#ifdef CONFIG_CGROUP_SCHED
		   "  group-path"
#endif
		   "\n");
	SEQ_printf(m, "-------------------------------------------------------"
		   "------------------------------------------------------"
		   "------------------------------------------------------"
#ifdef CONFIG_NUMA_BALANCING
		   "--------------"
#endif
#ifdef CONFIG_CGROUP_SCHED
		   "--------------"
#endif
		   "\n");

	rcu_read_lock();
	for_each_process_thread(g, p) {
		if (task_cpu(p) != rq_cpu)
			continue;

		print_task(m, rq, p);
	}
	rcu_read_unlock();
}

void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
{
	s64 left_vruntime = -1, zero_vruntime, right_vruntime = -1, left_deadline = -1, spread;
	u64 avruntime;
	struct sched_entity *last, *first, *root;
	struct rq *rq = cpu_rq(cpu);
	unsigned long flags;

#ifdef CONFIG_FAIR_GROUP_SCHED
	SEQ_printf(m, "\n");
	SEQ_printf_task_group_path(m, cfs_rq->tg, "cfs_rq[%d]:%s\n", cpu);
#else
	SEQ_printf(m, "\n");
	SEQ_printf(m, "cfs_rq[%d]:\n", cpu);
#endif

	raw_spin_rq_lock_irqsave(rq, flags);
	root = __pick_root_entity(cfs_rq);
	if (root)
		left_vruntime = root->min_vruntime;
	first = __pick_first_entity(cfs_rq);
	if (first)
		left_deadline = first->deadline;
	last = __pick_last_entity(cfs_rq);
	if (last)
		right_vruntime = last->vruntime;
	zero_vruntime = cfs_rq->zero_vruntime;
	avruntime = avg_vruntime(cfs_rq);
	raw_spin_rq_unlock_irqrestore(rq, flags);

	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "left_deadline",
			SPLIT_NS(left_deadline));
	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "left_vruntime",
			SPLIT_NS(left_vruntime));
	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "zero_vruntime",
			SPLIT_NS(zero_vruntime));
	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "avg_vruntime",
			SPLIT_NS(avruntime));
	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "right_vruntime",
			SPLIT_NS(right_vruntime));
	spread = right_vruntime - left_vruntime;
	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "spread", SPLIT_NS(spread));
	SEQ_printf(m, "  .%-30s: %d\n", "nr_queued", cfs_rq->nr_queued);
	SEQ_printf(m, "  .%-30s: %d\n", "h_nr_runnable", cfs_rq->h_nr_runnable);
	SEQ_printf(m, "  .%-30s: %d\n", "h_nr_queued", cfs_rq->h_nr_queued);
	SEQ_printf(m, "  .%-30s: %d\n", "h_nr_idle", cfs_rq->h_nr_idle);
	SEQ_printf(m, "  .%-30s: %ld\n", "load", cfs_rq->load.weight);
	SEQ_printf(m, "  .%-30s: %lu\n", "load_avg",
			cfs_rq->avg.load_avg);
	SEQ_printf(m, "  .%-30s: %lu\n", "runnable_avg",
			cfs_rq->avg.runnable_avg);
	SEQ_printf(m, "  .%-30s: %lu\n", "util_avg",
			cfs_rq->avg.util_avg);
	SEQ_printf(m, "  .%-30s: %u\n", "util_est",
			cfs_rq->avg.util_est);
	SEQ_printf(m, "  .%-30s: %ld\n", "removed.load_avg",
			cfs_rq->removed.load_avg);
	SEQ_printf(m, "  .%-30s: %ld\n", "removed.util_avg",
			cfs_rq->removed.util_avg);
	SEQ_printf(m, "  .%-30s: %ld\n", "removed.runnable_avg",
			cfs_rq->removed.runnable_avg);
#ifdef CONFIG_FAIR_GROUP_SCHED
	SEQ_printf(m, "  .%-30s: %lu\n", "tg_load_avg_contrib",
			cfs_rq->tg_load_avg_contrib);
	SEQ_printf(m, "  .%-30s: %ld\n", "tg_load_avg",
			atomic_long_read(&cfs_rq->tg->load_avg));
#endif /* CONFIG_FAIR_GROUP_SCHED */
#ifdef CONFIG_CFS_BANDWIDTH
	SEQ_printf(m, "  .%-30s: %d\n", "throttled",
			cfs_rq->throttled);
	SEQ_printf(m, "  .%-30s: %d\n", "throttle_count",
			cfs_rq->throttle_count);
#endif

#ifdef CONFIG_FAIR_GROUP_SCHED
	print_cfs_group_stats(m, cpu, cfs_rq->tg);
#endif
}

void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq)
{
#ifdef CONFIG_RT_GROUP_SCHED
	SEQ_printf(m, "\n");
	SEQ_printf_task_group_path(m, rt_rq->tg, "rt_rq[%d]:%s\n", cpu);
#else
	SEQ_printf(m, "\n");
	SEQ_printf(m, "rt_rq[%d]:\n", cpu);
#endif

#define P(x) \
	SEQ_printf(m, "  .%-30s: %Ld\n", #x, (long long)(rt_rq->x))
#define PU(x) \
	SEQ_printf(m, "  .%-30s: %lu\n", #x, (unsigned long)(rt_rq->x))
#define PN(x) \
	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", #x, SPLIT_NS(rt_rq->x))

	PU(rt_nr_running);

#ifdef CONFIG_RT_GROUP_SCHED
	P(rt_throttled);
	PN(rt_time);
	PN(rt_runtime);
#endif

#undef PN
#undef PU
#undef P
}

void print_dl_rq(struct seq_file *m, int cpu, struct dl_rq *dl_rq)
{
	struct dl_bw *dl_bw;

	SEQ_printf(m, "\n");
	SEQ_printf(m, "dl_rq[%d]:\n", cpu);

#define PU(x) \
	SEQ_printf(m, "  .%-30s: %lu\n", #x, (unsigned long)(dl_rq->x))

	PU(dl_nr_running);
	dl_bw = &cpu_rq(cpu)->rd->dl_bw;
	SEQ_printf(m, "  .%-30s: %lld\n", "dl_bw->bw", dl_bw->bw);
	SEQ_printf(m, "  .%-30s: %lld\n", "dl_bw->total_bw", dl_bw->total_bw);

#undef PU
}

static void print_cpu(struct seq_file *m, int cpu)
{
	struct rq *rq = cpu_rq(cpu);

#ifdef CONFIG_X86
	{
		unsigned int freq = cpu_khz ? : 1;

		SEQ_printf(m, "cpu#%d, %u.%03u MHz\n",
			   cpu, freq / 1000, (freq % 1000));
	}
#else /* !CONFIG_X86: */
	SEQ_printf(m, "cpu#%d\n", cpu);
#endif /* !CONFIG_X86 */

#define P(x)								\
do {									\
	if (sizeof(rq->x) == 4)						\
		SEQ_printf(m, "  .%-30s: %d\n", #x, (int)(rq->x));	\
	else								\
		SEQ_printf(m, "  .%-30s: %Ld\n", #x, (long long)(rq->x));\
} while (0)

#define PN(x) \
	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", #x, SPLIT_NS(rq->x))

	P(nr_running);
	P(nr_switches);
	P(nr_uninterruptible);
	PN(next_balance);
	SEQ_printf(m, "  .%-30s: %ld\n", "curr->pid", (long)(task_pid_nr(rq->curr)));
	PN(clock);
	PN(clock_task);
#undef P
#undef PN

#define P64(n) SEQ_printf(m, "  .%-30s: %Ld\n", #n, rq->n);
	P64(avg_idle);
	P64(max_idle_balance_cost);
#undef P64

#define P(n) SEQ_printf(m, "  .%-30s: %d\n", #n, schedstat_val(rq->n));
	if (schedstat_enabled()) {
		P(yld_count);
		P(sched_count);
		P(sched_goidle);
		P(ttwu_count);
		P(ttwu_local);
	}
#undef P

	print_cfs_stats(m, cpu);
	print_rt_stats(m, cpu);
	print_dl_stats(m, cpu);

	print_rq(m, rq, cpu);
	SEQ_printf(m, "\n");
}

static const char *sched_tunable_scaling_names[] = {
	"none",
	"logarithmic",
	"linear"
};

static void sched_debug_header(struct seq_file *m)
{
	u64 ktime, sched_clk, cpu_clk;
	unsigned long flags;

	local_irq_save(flags);
	ktime = ktime_to_ns(ktime_get());
	sched_clk = sched_clock();
	cpu_clk = local_clock();
	local_irq_restore(flags);

	SEQ_printf(m, "Sched Debug Version: v0.11, %s %.*s\n",
		init_utsname()->release,
		(int)strcspn(init_utsname()->version, " "),
		init_utsname()->version);

#define P(x) \
	SEQ_printf(m, "%-40s: %Ld\n", #x, (long long)(x))
#define PN(x) \
	SEQ_printf(m, "%-40s: %Ld.%06ld\n", #x, SPLIT_NS(x))
	PN(ktime);
	PN(sched_clk);
	PN(cpu_clk);
	P(jiffies);
#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
	P(sched_clock_stable());
#endif
#undef PN
#undef P

	SEQ_printf(m, "\n");
	SEQ_printf(m, "sysctl_sched\n");

#define P(x) \
	SEQ_printf(m, "  .%-40s: %Ld\n", #x, (long long)(x))
#define PN(x) \
	SEQ_printf(m, "  .%-40s: %Ld.%06ld\n", #x, SPLIT_NS(x))
	PN(sysctl_sched_base_slice);
	P(sysctl_sched_features);
#undef PN
#undef P

	SEQ_printf(m, "  .%-40s: %d (%s)\n",
		"sysctl_sched_tunable_scaling",
		sysctl_sched_tunable_scaling,
		sched_tunable_scaling_names[sysctl_sched_tunable_scaling]);
	SEQ_printf(m, "\n");
}

static int sched_debug_show(struct seq_file *m, void *v)
{
	int cpu = (unsigned long)(v - 2);

	if (cpu != -1)
		print_cpu(m, cpu);
	else
		sched_debug_header(m);

	return 0;
}

void sysrq_sched_debug_show(void)
{
	int cpu;

	sched_debug_header(NULL);
	for_each_online_cpu(cpu) {
		/*
		 * Need to reset softlockup watchdogs on all CPUs, because
		 * another CPU might be blocked waiting for us to process
		 * an IPI or stop_machine.
		 */
		touch_nmi_watchdog();
		touch_all_softlockup_watchdogs();
		print_cpu(NULL, cpu);
	}
}

/*
 * This iterator needs some explanation.
 * It returns 1 for the header position.
 * This means 2 is CPU 0.
 * In a hotplugged system some CPUs, including CPU 0, may be missing so we have
 * to use cpumask_* to iterate over the CPUs.
 */
static void *sched_debug_start(struct seq_file *file, loff_t *offset)
{
	unsigned long n = *offset;

	if (n == 0)
		return (void *) 1;

	n--;

	if (n > 0)
		n = cpumask_next(n - 1, cpu_online_mask);
	else
		n = cpumask_first(cpu_online_mask);

	*offset = n + 1;

	if (n < nr_cpu_ids)
		return (void *)(unsigned long)(n + 2);

	return NULL;
}

static void *sched_debug_next(struct seq_file *file, void *data, loff_t *offset)
{
	(*offset)++;
	return sched_debug_start(file, offset);
}

static void sched_debug_stop(struct seq_file *file, void *data)
{
}

static const struct seq_operations sched_debug_sops = {
	.start		= sched_debug_start,
	.next		= sched_debug_next,
	.stop		= sched_debug_stop,
	.show		= sched_debug_show,
};

#define __PS(S, F) SEQ_printf(m, "%-45s:%21Ld\n", S, (long long)(F))
#define __P(F) __PS(#F, F)
#define   P(F) __PS(#F, p->F)
#define   PM(F, M) __PS(#F, p->F & (M))
#define __PSN(S, F) SEQ_printf(m, "%-45s:%14Ld.%06ld\n", S, SPLIT_NS((long long)(F)))
#define __PN(F) __PSN(#F, F)
#define   PN(F) __PSN(#F, p->F)


#ifdef CONFIG_NUMA_BALANCING
void print_numa_stats(struct seq_file *m, int node, unsigned long tsf,
		unsigned long tpf, unsigned long gsf, unsigned long gpf)
{
	SEQ_printf(m, "numa_faults node=%d ", node);
	SEQ_printf(m, "task_private=%lu task_shared=%lu ", tpf, tsf);
	SEQ_printf(m, "group_private=%lu group_shared=%lu\n", gpf, gsf);
}
#endif


static void sched_show_numa(struct task_struct *p, struct seq_file *m)
{
#ifdef CONFIG_NUMA_BALANCING
	if (p->mm)
		P(mm->numa_scan_seq);

	P(numa_pages_migrated);
	P(numa_preferred_nid);
	P(total_numa_faults);
	SEQ_printf(m, "current_node=%d, numa_group_id=%d\n",
			task_node(p), task_numa_group_id(p));
	show_numa_stats(p, m);
#endif /* CONFIG_NUMA_BALANCING */
}

void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns,
						  struct seq_file *m)
{
	unsigned long nr_switches;

	SEQ_printf(m, "%s (%d, #threads: %d)\n", p->comm, task_pid_nr_ns(p, ns),
						get_nr_threads(p));
	SEQ_printf(m,
		"---------------------------------------------------------"
		"----------\n");

#define P_SCHEDSTAT(F)  __PS(#F, schedstat_val(p->stats.F))
#define PN_SCHEDSTAT(F) __PSN(#F, schedstat_val(p->stats.F))

	PN(se.exec_start);
	PN(se.vruntime);
	PN(se.sum_exec_runtime);

	nr_switches = p->nvcsw + p->nivcsw;

	P(se.nr_migrations);

	if (schedstat_enabled()) {
		u64 avg_atom, avg_per_cpu;

		PN_SCHEDSTAT(sum_sleep_runtime);
		PN_SCHEDSTAT(sum_block_runtime);
		PN_SCHEDSTAT(wait_start);
		PN_SCHEDSTAT(sleep_start);
		PN_SCHEDSTAT(block_start);
		PN_SCHEDSTAT(sleep_max);
		PN_SCHEDSTAT(block_max);
		PN_SCHEDSTAT(exec_max);
		PN_SCHEDSTAT(slice_max);
		PN_SCHEDSTAT(wait_max);
		PN_SCHEDSTAT(wait_sum);
		P_SCHEDSTAT(wait_count);
		PN_SCHEDSTAT(iowait_sum);
		P_SCHEDSTAT(iowait_count);
		P_SCHEDSTAT(nr_migrations_cold);
		P_SCHEDSTAT(nr_failed_migrations_affine);
		P_SCHEDSTAT(nr_failed_migrations_running);
		P_SCHEDSTAT(nr_failed_migrations_hot);
		P_SCHEDSTAT(nr_forced_migrations);
		P_SCHEDSTAT(nr_wakeups);
		P_SCHEDSTAT(nr_wakeups_sync);
		P_SCHEDSTAT(nr_wakeups_migrate);
		P_SCHEDSTAT(nr_wakeups_local);
		P_SCHEDSTAT(nr_wakeups_remote);
		P_SCHEDSTAT(nr_wakeups_affine);
		P_SCHEDSTAT(nr_wakeups_affine_attempts);
		P_SCHEDSTAT(nr_wakeups_passive);
		P_SCHEDSTAT(nr_wakeups_idle);

		avg_atom = p->se.sum_exec_runtime;
		if (nr_switches)
			avg_atom = div64_ul(avg_atom, nr_switches);
		else
			avg_atom = -1LL;

		avg_per_cpu = p->se.sum_exec_runtime;
		if (p->se.nr_migrations) {
			avg_per_cpu = div64_u64(avg_per_cpu,
						p->se.nr_migrations);
		} else {
			avg_per_cpu = -1LL;
		}

		__PN(avg_atom);
		__PN(avg_per_cpu);

#ifdef CONFIG_SCHED_CORE
		PN_SCHEDSTAT(core_forceidle_sum);
#endif
	}

	__P(nr_switches);
	__PS("nr_voluntary_switches", p->nvcsw);
	__PS("nr_involuntary_switches", p->nivcsw);

	P(se.load.weight);
	P(se.avg.load_sum);
	P(se.avg.runnable_sum);
	P(se.avg.util_sum);
	P(se.avg.load_avg);
	P(se.avg.runnable_avg);
	P(se.avg.util_avg);
	P(se.avg.last_update_time);
	PM(se.avg.util_est, ~UTIL_AVG_UNCHANGED);
#ifdef CONFIG_UCLAMP_TASK
	__PS("uclamp.min", p->uclamp_req[UCLAMP_MIN].value);
	__PS("uclamp.max", p->uclamp_req[UCLAMP_MAX].value);
	__PS("effective uclamp.min", uclamp_eff_value(p, UCLAMP_MIN));
	__PS("effective uclamp.max", uclamp_eff_value(p, UCLAMP_MAX));
#endif /* CONFIG_UCLAMP_TASK */
	P(policy);
	P(prio);
	if (task_has_dl_policy(p)) {
		P(dl.runtime);
		P(dl.deadline);
	} else if (fair_policy(p->policy)) {
		P(se.slice);
	}
#ifdef CONFIG_SCHED_CLASS_EXT
	__PS("ext.enabled", task_on_scx(p));
#endif
#undef PN_SCHEDSTAT
#undef P_SCHEDSTAT

	{
		unsigned int this_cpu = raw_smp_processor_id();
		u64 t0, t1;

		t0 = cpu_clock(this_cpu);
		t1 = cpu_clock(this_cpu);
		__PS("clock-delta", t1-t0);
	}

	sched_show_numa(p, m);
}

void proc_sched_set_task(struct task_struct *p)
{
#ifdef CONFIG_SCHEDSTATS
	memset(&p->stats, 0, sizeof(p->stats));
#endif
}

void resched_latency_warn(int cpu, u64 latency)
{
	static DEFINE_RATELIMIT_STATE(latency_check_ratelimit, 60 * 60 * HZ, 1);

	if (likely(!__ratelimit(&latency_check_ratelimit)))
		return;

	pr_err("sched: CPU %d need_resched set for > %llu ns (%d ticks) without schedule\n",
	       cpu, latency, cpu_rq(cpu)->ticks_without_resched);
	dump_stack();
}