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 /* 96 * Blocking time is in units of nanosecs, so shift by 97 * 20 to get a milliseconds-range estimation of the 98 * amount of time that the task spent sleeping: 99 */ 100 if (unlikely(prof_on == SLEEP_PROFILING)) { 101 profile_hits(SLEEP_PROFILING, 102 (void *)get_wchan(p), 103 delta >> 20); 104 } 105 account_scheduler_latency(p, delta >> 10, 0); 106 } 107 } 108 } 109 110 /* 111 * Current schedstat API version. 112 * 113 * Bump this up when changing the output format or the meaning of an existing 114 * format, so that tools can adapt (or abort) 115 */ 116 #define SCHEDSTAT_VERSION 15 117 118 static int show_schedstat(struct seq_file *seq, void *v) 119 { 120 int cpu; 121 122 if (v == (void *)1) { 123 seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION); 124 seq_printf(seq, "timestamp %lu\n", jiffies); 125 } else { 126 struct rq *rq; 127 #ifdef CONFIG_SMP 128 struct sched_domain *sd; 129 int dcount = 0; 130 #endif 131 cpu = (unsigned long)(v - 2); 132 rq = cpu_rq(cpu); 133 134 /* runqueue-specific stats */ 135 seq_printf(seq, 136 "cpu%d %u 0 %u %u %u %u %llu %llu %lu", 137 cpu, rq->yld_count, 138 rq->sched_count, rq->sched_goidle, 139 rq->ttwu_count, rq->ttwu_local, 140 rq->rq_cpu_time, 141 rq->rq_sched_info.run_delay, rq->rq_sched_info.pcount); 142 143 seq_printf(seq, "\n"); 144 145 #ifdef CONFIG_SMP 146 /* domain-specific stats */ 147 rcu_read_lock(); 148 for_each_domain(cpu, sd) { 149 enum cpu_idle_type itype; 150 151 seq_printf(seq, "domain%d %*pb", dcount++, 152 cpumask_pr_args(sched_domain_span(sd))); 153 for (itype = CPU_IDLE; itype < CPU_MAX_IDLE_TYPES; 154 itype++) { 155 seq_printf(seq, " %u %u %u %u %u %u %u %u", 156 sd->lb_count[itype], 157 sd->lb_balanced[itype], 158 sd->lb_failed[itype], 159 sd->lb_imbalance[itype], 160 sd->lb_gained[itype], 161 sd->lb_hot_gained[itype], 162 sd->lb_nobusyq[itype], 163 sd->lb_nobusyg[itype]); 164 } 165 seq_printf(seq, 166 " %u %u %u %u %u %u %u %u %u %u %u %u\n", 167 sd->alb_count, sd->alb_failed, sd->alb_pushed, 168 sd->sbe_count, sd->sbe_balanced, sd->sbe_pushed, 169 sd->sbf_count, sd->sbf_balanced, sd->sbf_pushed, 170 sd->ttwu_wake_remote, sd->ttwu_move_affine, 171 sd->ttwu_move_balance); 172 } 173 rcu_read_unlock(); 174 #endif 175 } 176 return 0; 177 } 178 179 /* 180 * This iterator needs some explanation. 181 * It returns 1 for the header position. 182 * This means 2 is cpu 0. 183 * In a hotplugged system some CPUs, including cpu 0, may be missing so we have 184 * to use cpumask_* to iterate over the CPUs. 185 */ 186 static void *schedstat_start(struct seq_file *file, loff_t *offset) 187 { 188 unsigned long n = *offset; 189 190 if (n == 0) 191 return (void *) 1; 192 193 n--; 194 195 if (n > 0) 196 n = cpumask_next(n - 1, cpu_online_mask); 197 else 198 n = cpumask_first(cpu_online_mask); 199 200 *offset = n + 1; 201 202 if (n < nr_cpu_ids) 203 return (void *)(unsigned long)(n + 2); 204 205 return NULL; 206 } 207 208 static void *schedstat_next(struct seq_file *file, void *data, loff_t *offset) 209 { 210 (*offset)++; 211 212 return schedstat_start(file, offset); 213 } 214 215 static void schedstat_stop(struct seq_file *file, void *data) 216 { 217 } 218 219 static const struct seq_operations schedstat_sops = { 220 .start = schedstat_start, 221 .next = schedstat_next, 222 .stop = schedstat_stop, 223 .show = show_schedstat, 224 }; 225 226 static int __init proc_schedstat_init(void) 227 { 228 proc_create_seq("schedstat", 0, NULL, &schedstat_sops); 229 return 0; 230 } 231 subsys_initcall(proc_schedstat_init); 232