1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * /proc/schedstat implementation 4 */ 5 6 void __update_stats_wait_start(struct rq *rq, struct task_struct *p, 7 struct sched_statistics *stats) 8 { 9 u64 wait_start, prev_wait_start; 10 11 wait_start = rq_clock(rq); 12 prev_wait_start = schedstat_val(stats->wait_start); 13 14 if (p && likely(wait_start > prev_wait_start)) 15 wait_start -= prev_wait_start; 16 17 __schedstat_set(stats->wait_start, wait_start); 18 } 19 20 void __update_stats_wait_end(struct rq *rq, struct task_struct *p, 21 struct sched_statistics *stats) 22 { 23 u64 delta = rq_clock(rq) - schedstat_val(stats->wait_start); 24 25 if (p) { 26 if (task_on_rq_migrating(p)) { 27 /* 28 * Preserve migrating task's wait time so wait_start 29 * time stamp can be adjusted to accumulate wait time 30 * prior to migration. 31 */ 32 __schedstat_set(stats->wait_start, delta); 33 34 return; 35 } 36 37 trace_sched_stat_wait(p, delta); 38 } 39 40 __schedstat_set(stats->wait_max, 41 max(schedstat_val(stats->wait_max), delta)); 42 __schedstat_inc(stats->wait_count); 43 __schedstat_add(stats->wait_sum, delta); 44 __schedstat_set(stats->wait_start, 0); 45 } 46 47 void __update_stats_enqueue_sleeper(struct rq *rq, struct task_struct *p, 48 struct sched_statistics *stats) 49 { 50 u64 sleep_start, block_start; 51 52 sleep_start = schedstat_val(stats->sleep_start); 53 block_start = schedstat_val(stats->block_start); 54 55 if (sleep_start) { 56 u64 delta = rq_clock(rq) - sleep_start; 57 58 if ((s64)delta < 0) 59 delta = 0; 60 61 if (unlikely(delta > schedstat_val(stats->sleep_max))) 62 __schedstat_set(stats->sleep_max, delta); 63 64 __schedstat_set(stats->sleep_start, 0); 65 __schedstat_add(stats->sum_sleep_runtime, delta); 66 67 if (p) { 68 account_scheduler_latency(p, delta >> 10, 1); 69 trace_sched_stat_sleep(p, delta); 70 } 71 } 72 73 if (block_start) { 74 u64 delta = rq_clock(rq) - block_start; 75 76 if ((s64)delta < 0) 77 delta = 0; 78 79 if (unlikely(delta > schedstat_val(stats->block_max))) 80 __schedstat_set(stats->block_max, delta); 81 82 __schedstat_set(stats->block_start, 0); 83 __schedstat_add(stats->sum_sleep_runtime, delta); 84 __schedstat_add(stats->sum_block_runtime, delta); 85 86 if (p) { 87 if (p->in_iowait) { 88 __schedstat_add(stats->iowait_sum, delta); 89 __schedstat_inc(stats->iowait_count); 90 trace_sched_stat_iowait(p, delta); 91 } 92 93 trace_sched_stat_blocked(p, delta); 94 95 account_scheduler_latency(p, delta >> 10, 0); 96 } 97 } 98 } 99 100 /* 101 * Current schedstat API version. 102 * 103 * Bump this up when changing the output format or the meaning of an existing 104 * format, so that tools can adapt (or abort) 105 */ 106 #define SCHEDSTAT_VERSION 15 107 108 static int show_schedstat(struct seq_file *seq, void *v) 109 { 110 int cpu; 111 112 if (v == (void *)1) { 113 seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION); 114 seq_printf(seq, "timestamp %lu\n", jiffies); 115 } else { 116 struct rq *rq; 117 #ifdef CONFIG_SMP 118 struct sched_domain *sd; 119 int dcount = 0; 120 #endif 121 cpu = (unsigned long)(v - 2); 122 rq = cpu_rq(cpu); 123 124 /* runqueue-specific stats */ 125 seq_printf(seq, 126 "cpu%d %u 0 %u %u %u %u %llu %llu %lu", 127 cpu, rq->yld_count, 128 rq->sched_count, rq->sched_goidle, 129 rq->ttwu_count, rq->ttwu_local, 130 rq->rq_cpu_time, 131 rq->rq_sched_info.run_delay, rq->rq_sched_info.pcount); 132 133 seq_printf(seq, "\n"); 134 135 #ifdef CONFIG_SMP 136 /* domain-specific stats */ 137 rcu_read_lock(); 138 for_each_domain(cpu, sd) { 139 enum cpu_idle_type itype; 140 141 seq_printf(seq, "domain%d %*pb", dcount++, 142 cpumask_pr_args(sched_domain_span(sd))); 143 for (itype = CPU_IDLE; itype < CPU_MAX_IDLE_TYPES; 144 itype++) { 145 seq_printf(seq, " %u %u %u %u %u %u %u %u", 146 sd->lb_count[itype], 147 sd->lb_balanced[itype], 148 sd->lb_failed[itype], 149 sd->lb_imbalance[itype], 150 sd->lb_gained[itype], 151 sd->lb_hot_gained[itype], 152 sd->lb_nobusyq[itype], 153 sd->lb_nobusyg[itype]); 154 } 155 seq_printf(seq, 156 " %u %u %u %u %u %u %u %u %u %u %u %u\n", 157 sd->alb_count, sd->alb_failed, sd->alb_pushed, 158 sd->sbe_count, sd->sbe_balanced, sd->sbe_pushed, 159 sd->sbf_count, sd->sbf_balanced, sd->sbf_pushed, 160 sd->ttwu_wake_remote, sd->ttwu_move_affine, 161 sd->ttwu_move_balance); 162 } 163 rcu_read_unlock(); 164 #endif 165 } 166 return 0; 167 } 168 169 /* 170 * This iterator needs some explanation. 171 * It returns 1 for the header position. 172 * This means 2 is cpu 0. 173 * In a hotplugged system some CPUs, including cpu 0, may be missing so we have 174 * to use cpumask_* to iterate over the CPUs. 175 */ 176 static void *schedstat_start(struct seq_file *file, loff_t *offset) 177 { 178 unsigned long n = *offset; 179 180 if (n == 0) 181 return (void *) 1; 182 183 n--; 184 185 if (n > 0) 186 n = cpumask_next(n - 1, cpu_online_mask); 187 else 188 n = cpumask_first(cpu_online_mask); 189 190 *offset = n + 1; 191 192 if (n < nr_cpu_ids) 193 return (void *)(unsigned long)(n + 2); 194 195 return NULL; 196 } 197 198 static void *schedstat_next(struct seq_file *file, void *data, loff_t *offset) 199 { 200 (*offset)++; 201 202 return schedstat_start(file, offset); 203 } 204 205 static void schedstat_stop(struct seq_file *file, void *data) 206 { 207 } 208 209 static const struct seq_operations schedstat_sops = { 210 .start = schedstat_start, 211 .next = schedstat_next, 212 .stop = schedstat_stop, 213 .show = show_schedstat, 214 }; 215 216 static int __init proc_schedstat_init(void) 217 { 218 proc_create_seq("schedstat", 0, NULL, &schedstat_sops); 219 return 0; 220 } 221 subsys_initcall(proc_schedstat_init); 222