kernel/sched/stats.h

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