1 files changed, 231 insertions, 70 deletions

diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index c1eb9a1afd13..41caa22e0680 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -6,6 +6,9 @@
  *
  * 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
@@ -90,10 +93,10 @@ static void sched_feat_enable(int i)
 {
 	static_key_enable_cpuslocked(&sched_feat_keys[i]);
 }
-#else
+#else /* !CONFIG_JUMP_LABEL: */
 static void sched_feat_disable(int i) { };
 static void sched_feat_enable(int i) { };
-#endif /* CONFIG_JUMP_LABEL */
+#endif /* !CONFIG_JUMP_LABEL */
 
 static int sched_feat_set(char *cmp)
 {
@@ -166,8 +169,6 @@ static const struct file_operations sched_feat_fops = {
 	.release	= single_release,
 };
 
-#ifdef CONFIG_SMP
-
 static ssize_t sched_scaling_write(struct file *filp, const char __user *ubuf,
 				   size_t cnt, loff_t *ppos)
 {
@@ -214,8 +215,6 @@ static const struct file_operations sched_scaling_fops = {
 	.release	= single_release,
 };
 
-#endif /* SMP */
-
 #ifdef CONFIG_PREEMPT_DYNAMIC
 
 static ssize_t sched_dynamic_write(struct file *filp, const char __user *ubuf,
@@ -244,12 +243,15 @@ static ssize_t sched_dynamic_write(struct file *filp, const char __user *ubuf,
 
 static int sched_dynamic_show(struct seq_file *m, void *v)
 {
-	static const char * preempt_modes[] = {
-		"none", "voluntary", "full"
-	};
-	int i;
+	int i = IS_ENABLED(CONFIG_PREEMPT_RT) * 2;
+	int j;
 
-	for (i = 0; i < ARRAY_SIZE(preempt_modes); i++) {
+	/* 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]);
@@ -280,7 +282,6 @@ static const struct file_operations sched_dynamic_fops = {
 
 __read_mostly bool sched_debug_verbose;
 
-#ifdef CONFIG_SMP
 static struct dentry           *sd_dentry;
 
 
@@ -291,7 +292,7 @@ static ssize_t sched_verbose_write(struct file *filp, const char __user *ubuf,
 	bool orig;
 
 	cpus_read_lock();
-	mutex_lock(&sched_domains_mutex);
+	sched_domains_mutex_lock();
 
 	orig = sched_debug_verbose;
 	result = debugfs_write_file_bool(filp, ubuf, cnt, ppos);
@@ -303,14 +304,11 @@ static ssize_t sched_verbose_write(struct file *filp, const char __user *ubuf,
 		sd_dentry = NULL;
 	}
 
-	mutex_unlock(&sched_domains_mutex);
+	sched_domains_mutex_unlock();
 	cpus_read_unlock();
 
 	return result;
 }
-#else
-#define sched_verbose_write debugfs_write_file_bool
-#endif
 
 static const struct file_operations sched_verbose_fops = {
 	.read =         debugfs_read_file_bool,
@@ -333,8 +331,163 @@ static const struct file_operations sched_debug_fops = {
 	.release	= seq_release,
 };
 
+enum dl_param {
+	DL_RUNTIME = 0,
+	DL_PERIOD,
+};
+
+static unsigned long fair_server_period_max = (1UL << 22) * NSEC_PER_USEC; /* ~4 seconds */
+static unsigned long fair_server_period_min = (100) * NSEC_PER_USEC;     /* 100 us */
+
+static ssize_t sched_fair_server_write(struct file *filp, const char __user *ubuf,
+				       size_t cnt, loff_t *ppos, enum dl_param param)
+{
+	long cpu = (long) ((struct seq_file *) filp->private_data)->private;
+	struct rq *rq = cpu_rq(cpu);
+	u64 runtime, period;
+	size_t err;
+	int retval;
+	u64 value;
+
+	err = kstrtoull_from_user(ubuf, cnt, 10, &value);
+	if (err)
+		return err;
+
+	scoped_guard (rq_lock_irqsave, rq) {
+		runtime  = rq->fair_server.dl_runtime;
+		period = rq->fair_server.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 > fair_server_period_max ||
+		    period < fair_server_period_min) {
+			return  -EINVAL;
+		}
+
+		update_rq_clock(rq);
+		dl_server_stop(&rq->fair_server);
+
+		retval = dl_server_apply_params(&rq->fair_server, runtime, period, 0);
+		if (retval)
+			cnt = retval;
+
+		if (!runtime)
+			printk_deferred("Fair server disabled in CPU %d, system may crash due to starvation.\n",
+					cpu_of(rq));
+
+		if (rq->cfs.h_nr_queued)
+			dl_server_start(&rq->fair_server);
+	}
+
+	*ppos += cnt;
+	return cnt;
+}
+
+static size_t sched_fair_server_show(struct seq_file *m, void *v, enum dl_param param)
+{
+	unsigned long cpu = (unsigned long) m->private;
+	struct rq *rq = cpu_rq(cpu);
+	u64 value;
+
+	switch (param) {
+	case DL_RUNTIME:
+		value = rq->fair_server.dl_runtime;
+		break;
+	case DL_PERIOD:
+		value = rq->fair_server.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)
+{
+	return sched_fair_server_write(filp, ubuf, cnt, ppos, DL_RUNTIME);
+}
+
+static int sched_fair_server_runtime_show(struct seq_file *m, void *v)
+{
+	return sched_fair_server_show(m, v, DL_RUNTIME);
+}
+
+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,
+};
+
+static ssize_t
+sched_fair_server_period_write(struct file *filp, const char __user *ubuf,
+			       size_t cnt, loff_t *ppos)
+{
+	return sched_fair_server_write(filp, ubuf, cnt, ppos, DL_PERIOD);
+}
+
+static int sched_fair_server_period_show(struct seq_file *m, void *v)
+{
+	return sched_fair_server_show(m, v, DL_PERIOD);
+}
+
+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,
+};
+
 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);
+	}
+}
+
 static __init int sched_init_debug(void)
 {
 	struct dentry __maybe_unused *numa;
@@ -352,15 +505,13 @@ static __init int sched_init_debug(void)
 	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);
 
-#ifdef CONFIG_SMP
 	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);
 
-	mutex_lock(&sched_domains_mutex);
+	sched_domains_mutex_lock();
 	update_sched_domain_debugfs();
-	mutex_unlock(&sched_domains_mutex);
-#endif
+	sched_domains_mutex_unlock();
 
 #ifdef CONFIG_NUMA_BALANCING
 	numa = debugfs_create_dir("numa_balancing", debugfs_sched);
@@ -370,16 +521,16 @@ static __init int sched_init_debug(void)
 	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
+#endif /* CONFIG_NUMA_BALANCING */
 
 	debugfs_create_file("debug", 0444, debugfs_sched, NULL, &sched_debug_fops);
 
+	debugfs_fair_server_init();
+
 	return 0;
 }
 late_initcall(sched_init_debug);
 
-#ifdef CONFIG_SMP
-
 static cpumask_var_t		sd_sysctl_cpus;
 
 static int sd_flags_show(struct seq_file *m, void *v)
@@ -426,6 +577,10 @@ static void register_sd(struct sched_domain *sd, struct dentry *parent)
 	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)
@@ -486,8 +641,6 @@ void dirty_sched_domain_sysctl(int cpu)
 		__cpumask_set_cpu(cpu, sd_sysctl_cpus);
 }
 
-#endif /* CONFIG_SMP */
-
 #ifdef CONFIG_FAIR_GROUP_SCHED
 static void print_cfs_group_stats(struct seq_file *m, int cpu, struct task_group *tg)
 {
@@ -524,18 +677,16 @@ static void print_cfs_group_stats(struct seq_file *m, int cpu, struct task_group
 	}
 
 	P(se->load.weight);
-#ifdef CONFIG_SMP
 	P(se->avg.load_avg);
 	P(se->avg.util_avg);
 	P(se->avg.runnable_avg);
-#endif
 
 #undef PN_SCHEDSTAT
 #undef PN
 #undef P_SCHEDSTAT
 #undef P
 }
-#endif
+#endif /* CONFIG_FAIR_GROUP_SCHED */
 
 #ifdef CONFIG_CGROUP_SCHED
 static DEFINE_SPINLOCK(sched_debug_lock);
@@ -580,27 +731,27 @@ print_task(struct seq_file *m, struct rq *rq, struct task_struct *p)
 	else
 		SEQ_printf(m, " %c", task_state_to_char(p));
 
-	SEQ_printf(m, "%15s %5d %9Ld.%06ld %c %9Ld.%06ld %9Ld.%06ld %9Ld.%06ld %9Ld %5d ",
+	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 %9lld.%06ld",
+	SEQ_printf(m, "%9lld.%06ld %9lld.%06ld %9lld.%06ld",
 		SPLIT_NS(schedstat_val_or_zero(p->stats.wait_sum)),
-		SPLIT_NS(p->se.sum_exec_runtime),
 		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));
+	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")
+	SEQ_printf_task_group_path(m, task_group(p), "        %s")
 #endif
 
 	SEQ_printf(m, "\n");
@@ -612,10 +763,26 @@ static void print_rq(struct seq_file *m, struct rq *rq, int rq_cpu)
 
 	SEQ_printf(m, "\n");
 	SEQ_printf(m, "runnable tasks:\n");
-	SEQ_printf(m, " S            task   PID         tree-key  switches  prio"
-		   "     wait-time             sum-exec        sum-sleep\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, "-------------------------------------------------------"
-		   "------------------------------------------------------\n");
+		   "------------------------------------------------------"
+		   "------------------------------------------------------"
+#ifdef CONFIG_NUMA_BALANCING
+		   "--------------"
+#endif
+#ifdef CONFIG_CGROUP_SCHED
+		   "--------------"
+#endif
+		   "\n");
 
 	rcu_read_lock();
 	for_each_process_thread(g, p) {
@@ -629,7 +796,7 @@ static void print_rq(struct seq_file *m, struct rq *rq, int rq_cpu)
 
 void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
 {
-	s64 left_vruntime = -1, min_vruntime, right_vruntime = -1, left_deadline = -1, spread;
+	s64 left_vruntime = -1, zero_vruntime, right_vruntime = -1, left_deadline = -1, spread;
 	struct sched_entity *last, *first, *root;
 	struct rq *rq = cpu_rq(cpu);
 	unsigned long flags;
@@ -641,8 +808,6 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
 	SEQ_printf(m, "\n");
 	SEQ_printf(m, "cfs_rq[%d]:\n", cpu);
 #endif
-	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "exec_clock",
-			SPLIT_NS(cfs_rq->exec_clock));
 
 	raw_spin_rq_lock_irqsave(rq, flags);
 	root = __pick_root_entity(cfs_rq);
@@ -654,31 +819,26 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
 	last = __pick_last_entity(cfs_rq);
 	if (last)
 		right_vruntime = last->vruntime;
-	min_vruntime = cfs_rq->min_vruntime;
+	zero_vruntime = cfs_rq->zero_vruntime;
 	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", "min_vruntime",
-			SPLIT_NS(min_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(avg_vruntime(cfs_rq)));
 	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_spread_over",
-			cfs_rq->nr_spread_over);
-	SEQ_printf(m, "  .%-30s: %d\n", "nr_running", cfs_rq->nr_running);
-	SEQ_printf(m, "  .%-30s: %d\n", "h_nr_running", cfs_rq->h_nr_running);
-	SEQ_printf(m, "  .%-30s: %d\n", "idle_nr_running",
-			cfs_rq->idle_nr_running);
-	SEQ_printf(m, "  .%-30s: %d\n", "idle_h_nr_running",
-			cfs_rq->idle_h_nr_running);
+	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);
-#ifdef CONFIG_SMP
 	SEQ_printf(m, "  .%-30s: %lu\n", "load_avg",
 			cfs_rq->avg.load_avg);
 	SEQ_printf(m, "  .%-30s: %lu\n", "runnable_avg",
@@ -698,8 +858,7 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
 			cfs_rq->tg_load_avg_contrib);
 	SEQ_printf(m, "  .%-30s: %ld\n", "tg_load_avg",
 			atomic_long_read(&cfs_rq->tg->load_avg));
-#endif
-#endif
+#endif /* CONFIG_FAIR_GROUP_SCHED */
 #ifdef CONFIG_CFS_BANDWIDTH
 	SEQ_printf(m, "  .%-30s: %d\n", "throttled",
 			cfs_rq->throttled);
@@ -730,9 +889,12 @@ void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq)
 	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
@@ -750,11 +912,7 @@ void print_dl_rq(struct seq_file *m, int cpu, struct dl_rq *dl_rq)
 	SEQ_printf(m, "  .%-30s: %lu\n", #x, (unsigned long)(dl_rq->x))
 
 	PU(dl_nr_running);
-#ifdef CONFIG_SMP
 	dl_bw = &cpu_rq(cpu)->rd->dl_bw;
-#else
-	dl_bw = &dl_rq->dl_bw;
-#endif
 	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);
 
@@ -772,9 +930,9 @@ static void print_cpu(struct seq_file *m, int cpu)
 		SEQ_printf(m, "cpu#%d, %u.%03u MHz\n",
 			   cpu, freq / 1000, (freq % 1000));
 	}
-#else
+#else /* !CONFIG_X86: */
 	SEQ_printf(m, "cpu#%d\n", cpu);
-#endif
+#endif /* !CONFIG_X86 */
 
 #define P(x)								\
 do {									\
@@ -797,12 +955,10 @@ do {									\
 #undef P
 #undef PN
 
-#ifdef CONFIG_SMP
 #define P64(n) SEQ_printf(m, "  .%-30s: %Ld\n", #n, rq->n);
 	P64(avg_idle);
 	P64(max_idle_balance_cost);
 #undef P64
-#endif
 
 #define P(n) SEQ_printf(m, "  .%-30s: %d\n", #n, schedstat_val(rq->n));
 	if (schedstat_enabled()) {
@@ -984,7 +1140,7 @@ static void sched_show_numa(struct task_struct *p, struct seq_file *m)
 	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
+#endif /* CONFIG_NUMA_BALANCING */
 }
 
 void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns,
@@ -1068,7 +1224,6 @@ void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns,
 	__PS("nr_involuntary_switches", p->nivcsw);
 
 	P(se.load.weight);
-#ifdef CONFIG_SMP
 	P(se.avg.load_sum);
 	P(se.avg.runnable_sum);
 	P(se.avg.util_sum);
@@ -1077,19 +1232,23 @@ void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns,
 	P(se.avg.util_avg);
 	P(se.avg.last_update_time);
 	PM(se.avg.util_est, ~UTIL_AVG_UNCHANGED);
-#endif
 #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
+#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
 
@@ -1116,8 +1275,10 @@ void resched_latency_warn(int cpu, u64 latency)
 {
 	static DEFINE_RATELIMIT_STATE(latency_check_ratelimit, 60 * 60 * HZ, 1);
 
-	WARN(__ratelimit(&latency_check_ratelimit),
-	     "sched: CPU %d need_resched set for > %llu ns (%d ticks) "
-	     "without schedule\n",
-	     cpu, latency, cpu_rq(cpu)->ticks_without_resched);
+	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();
 }