kernel/sched/debug.c

root/kernel/sched/debug.c
// 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();
}
Linux
