1// SPDX-License-Identifier: GPL-2.0
2/*
3 * /proc/schedstat implementation
4 */
5#include "sched.h"
6
7/*
8 * Current schedstat API version.
9 *
10 * Bump this up when changing the output format or the meaning of an existing
11 * format, so that tools can adapt (or abort)
12 */
13#define SCHEDSTAT_VERSION 15
14
15static int show_schedstat(struct seq_file *seq, void *v)
16{
17 int cpu;
18
19 if (v == (void *)1) {
20 seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION);
21 seq_printf(seq, "timestamp %lu\n", jiffies);
22 } else {
23 struct rq *rq;
24#ifdef CONFIG_SMP
25 struct sched_domain *sd;
26 int dcount = 0;
27#endif
28 cpu = (unsigned long)(v - 2);
29 rq = cpu_rq(cpu);
30
31 /* runqueue-specific stats */
32 seq_printf(seq,
33 "cpu%d %u 0 %u %u %u %u %llu %llu %lu",
34 cpu, rq->yld_count,
35 rq->sched_count, rq->sched_goidle,
36 rq->ttwu_count, rq->ttwu_local,
37 rq->rq_cpu_time,
38 rq->rq_sched_info.run_delay, rq->rq_sched_info.pcount);
39
40 seq_printf(seq, "\n");
41
42#ifdef CONFIG_SMP
43 /* domain-specific stats */
44 rcu_read_lock();
45 for_each_domain(cpu, sd) {
46 enum cpu_idle_type itype;
47
48 seq_printf(seq, "domain%d %*pb", dcount++,
49 cpumask_pr_args(sched_domain_span(sd)));
50 for (itype = CPU_IDLE; itype < CPU_MAX_IDLE_TYPES;
51 itype++) {
52 seq_printf(seq, " %u %u %u %u %u %u %u %u",
53 sd->lb_count[itype],
54 sd->lb_balanced[itype],
55 sd->lb_failed[itype],
56 sd->lb_imbalance[itype],
57 sd->lb_gained[itype],
58 sd->lb_hot_gained[itype],
59 sd->lb_nobusyq[itype],
60 sd->lb_nobusyg[itype]);
61 }
62 seq_printf(seq,
63 " %u %u %u %u %u %u %u %u %u %u %u %u\n",
64 sd->alb_count, sd->alb_failed, sd->alb_pushed,
65 sd->sbe_count, sd->sbe_balanced, sd->sbe_pushed,
66 sd->sbf_count, sd->sbf_balanced, sd->sbf_pushed,
67 sd->ttwu_wake_remote, sd->ttwu_move_affine,
68 sd->ttwu_move_balance);
69 }
70 rcu_read_unlock();
71#endif
72 }
73 return 0;
74}
75
76/*
77 * This itererator needs some explanation.
78 * It returns 1 for the header position.
79 * This means 2 is cpu 0.
80 * In a hotplugged system some CPUs, including cpu 0, may be missing so we have
81 * to use cpumask_* to iterate over the CPUs.
82 */
83static void *schedstat_start(struct seq_file *file, loff_t *offset)
84{
85 unsigned long n = *offset;
86
87 if (n == 0)
88 return (void *) 1;
89
90 n--;
91
92 if (n > 0)
93 n = cpumask_next(n - 1, cpu_online_mask);
94 else
95 n = cpumask_first(cpu_online_mask);
96
97 *offset = n + 1;
98
99 if (n < nr_cpu_ids)
100 return (void *)(unsigned long)(n + 2);
101
102 return NULL;
103}
104
105static void *schedstat_next(struct seq_file *file, void *data, loff_t *offset)
106{
107 (*offset)++;
108
109 return schedstat_start(file, offset);
110}
111
112static void schedstat_stop(struct seq_file *file, void *data)
113{
114}
115
116static const struct seq_operations schedstat_sops = {
117 .start = schedstat_start,
118 .next = schedstat_next,
119 .stop = schedstat_stop,
120 .show = show_schedstat,
121};
122
123static int __init proc_schedstat_init(void)
124{
125 proc_create_seq("schedstat", 0, NULL, &schedstat_sops);
126 return 0;
127}
128subsys_initcall(proc_schedstat_init);
129