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