1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _KERNEL_STATS_H 3 #define _KERNEL_STATS_H 4 5 #ifdef CONFIG_SCHEDSTATS 6 7 extern struct static_key_false sched_schedstats; 8 9 /* 10 * Expects runqueue lock to be held for atomicity of update 11 */ 12 static inline void 13 rq_sched_info_arrive(struct rq *rq, unsigned long long delta) 14 { 15 if (rq) { 16 rq->rq_sched_info.run_delay += delta; 17 rq->rq_sched_info.pcount++; 18 } 19 } 20 21 /* 22 * Expects runqueue lock to be held for atomicity of update 23 */ 24 static inline void 25 rq_sched_info_depart(struct rq *rq, unsigned long long delta) 26 { 27 if (rq) 28 rq->rq_cpu_time += delta; 29 } 30 31 static inline void 32 rq_sched_info_dequeue(struct rq *rq, unsigned long long delta) 33 { 34 if (rq) 35 rq->rq_sched_info.run_delay += delta; 36 } 37 #define schedstat_enabled() static_branch_unlikely(&sched_schedstats) 38 #define __schedstat_inc(var) do { var++; } while (0) 39 #define schedstat_inc(var) do { if (schedstat_enabled()) { var++; } } while (0) 40 #define __schedstat_add(var, amt) do { var += (amt); } while (0) 41 #define schedstat_add(var, amt) do { if (schedstat_enabled()) { var += (amt); } } while (0) 42 #define __schedstat_set(var, val) do { var = (val); } while (0) 43 #define schedstat_set(var, val) do { if (schedstat_enabled()) { var = (val); } } while (0) 44 #define schedstat_val(var) (var) 45 #define schedstat_val_or_zero(var) ((schedstat_enabled()) ? (var) : 0) 46 47 void __update_stats_wait_start(struct rq *rq, struct task_struct *p, 48 struct sched_statistics *stats); 49 50 void __update_stats_wait_end(struct rq *rq, struct task_struct *p, 51 struct sched_statistics *stats); 52 void __update_stats_enqueue_sleeper(struct rq *rq, struct task_struct *p, 53 struct sched_statistics *stats); 54 55 static inline void 56 check_schedstat_required(void) 57 { 58 if (schedstat_enabled()) 59 return; 60 61 /* Force schedstat enabled if a dependent tracepoint is active */ 62 if (trace_sched_stat_wait_enabled() || 63 trace_sched_stat_sleep_enabled() || 64 trace_sched_stat_iowait_enabled() || 65 trace_sched_stat_blocked_enabled() || 66 trace_sched_stat_runtime_enabled()) 67 printk_deferred_once("Scheduler tracepoints stat_sleep, stat_iowait, stat_blocked and stat_runtime require the kernel parameter schedstats=enable or kernel.sched_schedstats=1\n"); 68 } 69 70 #else /* !CONFIG_SCHEDSTATS: */ 71 72 static inline void rq_sched_info_arrive (struct rq *rq, unsigned long long delta) { } 73 static inline void rq_sched_info_dequeue(struct rq *rq, unsigned long long delta) { } 74 static inline void rq_sched_info_depart (struct rq *rq, unsigned long long delta) { } 75 # define schedstat_enabled() 0 76 # define __schedstat_inc(var) do { } while (0) 77 # define schedstat_inc(var) do { } while (0) 78 # define __schedstat_add(var, amt) do { } while (0) 79 # define schedstat_add(var, amt) do { } while (0) 80 # define __schedstat_set(var, val) do { } while (0) 81 # define schedstat_set(var, val) do { } while (0) 82 # define schedstat_val(var) 0 83 # define schedstat_val_or_zero(var) 0 84 85 # define __update_stats_wait_start(rq, p, stats) do { } while (0) 86 # define __update_stats_wait_end(rq, p, stats) do { } while (0) 87 # define __update_stats_enqueue_sleeper(rq, p, stats) do { } while (0) 88 # define check_schedstat_required() do { } while (0) 89 90 #endif /* CONFIG_SCHEDSTATS */ 91 92 static inline struct sched_statistics * 93 __schedstats_from_se(struct sched_entity *se) 94 { 95 #ifdef CONFIG_FAIR_GROUP_SCHED 96 if (!entity_is_task(se)) 97 return &container_of(se, struct cfs_tg_state, se)->stats; 98 #endif 99 return &task_of(se)->stats; 100 } 101 102 #ifdef CONFIG_PSI 103 void psi_task_change(struct task_struct *task, int clear, int set); 104 void psi_task_switch(struct task_struct *prev, struct task_struct *next, 105 bool sleep); 106 #ifdef CONFIG_IRQ_TIME_ACCOUNTING 107 void psi_account_irqtime(struct rq *rq, struct task_struct *curr, struct task_struct *prev); 108 #else /* !CONFIG_IRQ_TIME_ACCOUNTING: */ 109 static inline void psi_account_irqtime(struct rq *rq, struct task_struct *curr, 110 struct task_struct *prev) {} 111 #endif /* !CONFIG_IRQ_TIME_ACCOUNTING */ 112 /* 113 * PSI tracks state that persists across sleeps, such as iowaits and 114 * memory stalls. As a result, it has to distinguish between sleeps, 115 * where a task's runnable state changes, and migrations, where a task 116 * and its runnable state are being moved between CPUs and runqueues. 117 * 118 * A notable case is a task whose dequeue is delayed. PSI considers 119 * those sleeping, but because they are still on the runqueue they can 120 * go through migration requeues. In this case, *sleeping* states need 121 * to be transferred. 122 */ 123 static inline void psi_enqueue(struct task_struct *p, int flags) 124 { 125 int clear = 0, set = 0; 126 127 if (static_branch_likely(&psi_disabled)) 128 return; 129 130 /* Same runqueue, nothing changed for psi */ 131 if (flags & ENQUEUE_RESTORE) 132 return; 133 134 /* psi_sched_switch() will handle the flags */ 135 if (task_on_cpu(task_rq(p), p)) 136 return; 137 138 if (p->se.sched_delayed) { 139 /* CPU migration of "sleeping" task */ 140 WARN_ON_ONCE(!(flags & ENQUEUE_MIGRATED)); 141 if (p->in_memstall) 142 set |= TSK_MEMSTALL; 143 if (p->in_iowait) 144 set |= TSK_IOWAIT; 145 } else if (flags & ENQUEUE_MIGRATED) { 146 /* CPU migration of runnable task */ 147 set = TSK_RUNNING; 148 if (p->in_memstall) 149 set |= TSK_MEMSTALL | TSK_MEMSTALL_RUNNING; 150 } else { 151 /* Wakeup of new or sleeping task */ 152 if (p->in_iowait) 153 clear |= TSK_IOWAIT; 154 set = TSK_RUNNING; 155 if (p->in_memstall) 156 set |= TSK_MEMSTALL_RUNNING; 157 } 158 159 psi_task_change(p, clear, set); 160 } 161 162 static inline void psi_dequeue(struct task_struct *p, int flags) 163 { 164 if (static_branch_likely(&psi_disabled)) 165 return; 166 167 /* Same runqueue, nothing changed for psi */ 168 if (flags & DEQUEUE_SAVE) 169 return; 170 171 /* 172 * A voluntary sleep is a dequeue followed by a task switch. To 173 * avoid walking all ancestors twice, psi_task_switch() handles 174 * TSK_RUNNING and TSK_IOWAIT for us when it moves TSK_ONCPU. 175 * Do nothing here. 176 * 177 * In the SCHED_PROXY_EXECUTION case we may do sleeping 178 * dequeues that are not followed by a task switch, so check 179 * TSK_ONCPU is set to ensure the task switch is imminent. 180 * Otherwise clear the flags as usual. 181 */ 182 if ((flags & DEQUEUE_SLEEP) && (p->psi_flags & TSK_ONCPU)) 183 return; 184 185 /* 186 * When migrating a task to another CPU, clear all psi 187 * state. The enqueue callback above will work it out. 188 */ 189 psi_task_change(p, p->psi_flags, 0); 190 } 191 192 static inline void psi_ttwu_dequeue(struct task_struct *p) 193 { 194 if (static_branch_likely(&psi_disabled)) 195 return; 196 /* 197 * Is the task being migrated during a wakeup? Make sure to 198 * deregister its sleep-persistent psi states from the old 199 * queue, and let psi_enqueue() know it has to requeue. 200 */ 201 if (unlikely(p->psi_flags)) { 202 struct rq_flags rf; 203 struct rq *rq; 204 205 rq = __task_rq_lock(p, &rf); 206 psi_task_change(p, p->psi_flags, 0); 207 __task_rq_unlock(rq, p, &rf); 208 } 209 } 210 211 static inline void psi_sched_switch(struct task_struct *prev, 212 struct task_struct *next, 213 bool sleep) 214 { 215 if (static_branch_likely(&psi_disabled)) 216 return; 217 218 psi_task_switch(prev, next, sleep); 219 } 220 221 #else /* !CONFIG_PSI: */ 222 static inline void psi_enqueue(struct task_struct *p, bool migrate) {} 223 static inline void psi_dequeue(struct task_struct *p, bool migrate) {} 224 static inline void psi_ttwu_dequeue(struct task_struct *p) {} 225 static inline void psi_sched_switch(struct task_struct *prev, 226 struct task_struct *next, 227 bool sleep) {} 228 static inline void psi_account_irqtime(struct rq *rq, struct task_struct *curr, 229 struct task_struct *prev) {} 230 #endif /* !CONFIG_PSI */ 231 232 #ifdef CONFIG_SCHED_INFO 233 /* 234 * We are interested in knowing how long it was from the *first* time a 235 * task was queued to the time that it finally hit a CPU, we call this routine 236 * from dequeue_task() to account for possible rq->clock skew across CPUs. The 237 * delta taken on each CPU would annul the skew. 238 */ 239 static inline void sched_info_dequeue(struct rq *rq, struct task_struct *t) 240 { 241 unsigned long long delta = 0; 242 243 if (!t->sched_info.last_queued) 244 return; 245 246 delta = rq_clock(rq) - t->sched_info.last_queued; 247 t->sched_info.last_queued = 0; 248 t->sched_info.run_delay += delta; 249 if (delta > t->sched_info.max_run_delay) { 250 t->sched_info.max_run_delay = delta; 251 ktime_get_real_ts64(&t->sched_info.max_run_delay_ts); 252 } 253 if (delta && (!t->sched_info.min_run_delay || delta < t->sched_info.min_run_delay)) 254 t->sched_info.min_run_delay = delta; 255 rq_sched_info_dequeue(rq, delta); 256 } 257 258 /* 259 * Called when a task finally hits the CPU. We can now calculate how 260 * long it was waiting to run. We also note when it began so that we 261 * can keep stats on how long its time-slice is. 262 */ 263 static void sched_info_arrive(struct rq *rq, struct task_struct *t) 264 { 265 unsigned long long now, delta = 0; 266 267 if (!t->sched_info.last_queued) 268 return; 269 270 now = rq_clock(rq); 271 delta = now - t->sched_info.last_queued; 272 t->sched_info.last_queued = 0; 273 t->sched_info.run_delay += delta; 274 t->sched_info.last_arrival = now; 275 t->sched_info.pcount++; 276 if (delta > t->sched_info.max_run_delay) { 277 t->sched_info.max_run_delay = delta; 278 ktime_get_real_ts64(&t->sched_info.max_run_delay_ts); 279 } 280 if (delta && (!t->sched_info.min_run_delay || delta < t->sched_info.min_run_delay)) 281 t->sched_info.min_run_delay = delta; 282 283 rq_sched_info_arrive(rq, delta); 284 } 285 286 /* 287 * This function is only called from enqueue_task(), but also only updates 288 * the timestamp if it is already not set. It's assumed that 289 * sched_info_dequeue() will clear that stamp when appropriate. 290 */ 291 static inline void sched_info_enqueue(struct rq *rq, struct task_struct *t) 292 { 293 if (!t->sched_info.last_queued) 294 t->sched_info.last_queued = rq_clock(rq); 295 } 296 297 /* 298 * Called when a process ceases being the active-running process involuntarily 299 * due, typically, to expiring its time slice (this may also be called when 300 * switching to the idle task). Now we can calculate how long we ran. 301 * Also, if the process is still in the TASK_RUNNING state, call 302 * sched_info_enqueue() to mark that it has now again started waiting on 303 * the runqueue. 304 */ 305 static inline void sched_info_depart(struct rq *rq, struct task_struct *t) 306 { 307 unsigned long long delta = rq_clock(rq) - t->sched_info.last_arrival; 308 309 rq_sched_info_depart(rq, delta); 310 311 if (task_is_running(t)) 312 sched_info_enqueue(rq, t); 313 } 314 315 /* 316 * Called when tasks are switched involuntarily due, typically, to expiring 317 * their time slice. (This may also be called when switching to or from 318 * the idle task.) We are only called when prev != next. 319 */ 320 static inline void 321 sched_info_switch(struct rq *rq, struct task_struct *prev, struct task_struct *next) 322 { 323 /* 324 * prev now departs the CPU. It's not interesting to record 325 * stats about how efficient we were at scheduling the idle 326 * process, however. 327 */ 328 if (prev != rq->idle) 329 sched_info_depart(rq, prev); 330 331 if (next != rq->idle) 332 sched_info_arrive(rq, next); 333 } 334 335 #else /* !CONFIG_SCHED_INFO: */ 336 # define sched_info_enqueue(rq, t) do { } while (0) 337 # define sched_info_dequeue(rq, t) do { } while (0) 338 # define sched_info_switch(rq, t, next) do { } while (0) 339 #endif /* !CONFIG_SCHED_INFO */ 340 341 #endif /* _KERNEL_STATS_H */ 342