// SPDX-License-Identifier: GPL-2.0/* * /proc/schedstat implementation */ void __update_stats_wait_start(struct rq *rq, struct task_struct *p,			       struct sched_statistics *stats){	u64 wait_start, prev_wait_start; 	wait_start = rq_clock(rq);	prev_wait_start = schedstat_val(stats->wait_start); 	if (p && likely(wait_start > prev_wait_start))		wait_start -= prev_wait_start; 	__schedstat_set(stats->wait_start, wait_start);} void __update_stats_wait_end(struct rq *rq, struct task_struct *p,			     struct sched_statistics *stats){	u64 delta = rq_clock(rq) - schedstat_val(stats->wait_start); 	if (p) {		if (task_on_rq_migrating(p)) {			/*			 * Preserve migrating task's wait time so wait_start			 * time stamp can be adjusted to accumulate wait time			 * prior to migration.			 */			__schedstat_set(stats->wait_start, delta); 			return;		} 		trace_sched_stat_wait(p, delta);	} 	__schedstat_set(stats->wait_max,			max(schedstat_val(stats->wait_max), delta));	__schedstat_inc(stats->wait_count);	__schedstat_add(stats->wait_sum, delta);	__schedstat_set(stats->wait_start, 0);} void __update_stats_enqueue_sleeper(struct rq *rq, struct task_struct *p,				    struct sched_statistics *stats){	u64 sleep_start, block_start; 	sleep_start = schedstat_val(stats->sleep_start);	block_start = schedstat_val(stats->block_start); 	if (sleep_start) {		u64 delta = rq_clock(rq) - sleep_start; 		if ((s64)delta < 0)			delta = 0; 		if (unlikely(delta > schedstat_val(stats->sleep_max)))			__schedstat_set(stats->sleep_max, delta); 		__schedstat_set(stats->sleep_start, 0);		__schedstat_add(stats->sum_sleep_runtime, delta); 		if (p) {			account_scheduler_latency(p, delta >> 10, 1);			trace_sched_stat_sleep(p, delta);		}	} 	if (block_start) {		u64 delta = rq_clock(rq) - block_start; 		if ((s64)delta < 0)			delta = 0; 		if (unlikely(delta > schedstat_val(stats->block_max)))			__schedstat_set(stats->block_max, delta); 		__schedstat_set(stats->block_start, 0);		__schedstat_add(stats->sum_sleep_runtime, delta);		__schedstat_add(stats->sum_block_runtime, delta); 		if (p) {			if (p->in_iowait) {				__schedstat_add(stats->iowait_sum, delta);				__schedstat_inc(stats->iowait_count);				trace_sched_stat_iowait(p, delta);			} 			trace_sched_stat_blocked(p, delta); 			account_scheduler_latency(p, delta >> 10, 0);		}	}} /* * Current schedstat API version. * * Bump this up when changing the output format or the meaning of an existing * format, so that tools can adapt (or abort) */#define SCHEDSTAT_VERSION 16 static int show_schedstat(struct seq_file *seq, void *v){	int cpu; 	if (v == (void *)1) {		seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION);		seq_printf(seq, "timestamp %lu\n", jiffies);	} else {		struct rq *rq;#ifdef CONFIG_SMP		struct sched_domain *sd;		int dcount = 0;#endif		cpu = (unsigned long)(v - 2);		rq = cpu_rq(cpu); 		/* runqueue-specific stats */		seq_printf(seq,		    "cpu%d %u 0 %u %u %u %u %llu %llu %lu",		    cpu, rq->yld_count,		    rq->sched_count, rq->sched_goidle,		    rq->ttwu_count, rq->ttwu_local,		    rq->rq_cpu_time,		    rq->rq_sched_info.run_delay, rq->rq_sched_info.pcount); 		seq_printf(seq, "\n"); #ifdef CONFIG_SMP		/* domain-specific stats */		rcu_read_lock();		for_each_domain(cpu, sd) {			enum cpu_idle_type itype; 			seq_printf(seq, "domain%d %*pb", dcount++,				   cpumask_pr_args(sched_domain_span(sd)));			for (itype = 0; itype < CPU_MAX_IDLE_TYPES; itype++) {				seq_printf(seq, " %u %u %u %u %u %u %u %u",				    sd->lb_count[itype],				    sd->lb_balanced[itype],				    sd->lb_failed[itype],				    sd->lb_imbalance[itype],				    sd->lb_gained[itype],				    sd->lb_hot_gained[itype],				    sd->lb_nobusyq[itype],				    sd->lb_nobusyg[itype]);			}			seq_printf(seq,				   " %u %u %u %u %u %u %u %u %u %u %u %u\n",			    sd->alb_count, sd->alb_failed, sd->alb_pushed,			    sd->sbe_count, sd->sbe_balanced, sd->sbe_pushed,			    sd->sbf_count, sd->sbf_balanced, sd->sbf_pushed,			    sd->ttwu_wake_remote, sd->ttwu_move_affine,			    sd->ttwu_move_balance);		}		rcu_read_unlock();#endif	}	return 0;} /* * 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 *schedstat_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 *schedstat_next(struct seq_file *file, void *data, loff_t *offset){	(*offset)++; 	return schedstat_start(file, offset);} static void schedstat_stop(struct seq_file *file, void *data){} static const struct seq_operations schedstat_sops = {	.start = schedstat_start,	.next  = schedstat_next,	.stop  = schedstat_stop,	.show  = show_schedstat,}; static int __init proc_schedstat_init(void){	proc_create_seq("schedstat", 0, NULL, &schedstat_sops);	return 0;}subsys_initcall(proc_schedstat_init);