kernel/sched/stats.h

   1
   2 #ifdef CONFIG_SCHEDSTATS
   3
   4 /*
   5  * Expects runqueue lock to be held for atomicity of update
   6  */
   7 static inline void
   8 rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
   9 {
  10         if (rq) {
  11                 rq->rq_sched_info.run_delay += delta;
  12                 rq->rq_sched_info.pcount++;
  13         }
  14 }
  15
  16 /*
  17  * Expects runqueue lock to be held for atomicity of update
  18  */
  19 static inline void
  20 rq_sched_info_depart(struct rq *rq, unsigned long long delta)
  21 {
  22         if (rq)
  23                 rq->rq_cpu_time += delta;
  24 }
  25
  26 static inline void
  27 rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
  28 {
  29         if (rq)
  30                 rq->rq_sched_info.run_delay += delta;
  31 }
  32 # define schedstat_inc(rq, field)       do { (rq)->field++; } while (0)
  33 # define schedstat_add(rq, field, amt)  do { (rq)->field += (amt); } while (0)
  34 # define schedstat_set(var, val)        do { var = (val); } while (0)
  35 #else /* !CONFIG_SCHEDSTATS */
  36 static inline void
  37 rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
  38 {}
  39 static inline void
  40 rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
  41 {}
  42 static inline void
  43 rq_sched_info_depart(struct rq *rq, unsigned long long delta)
  44 {}
  45 # define schedstat_inc(rq, field)       do { } while (0)
  46 # define schedstat_add(rq, field, amt)  do { } while (0)
  47 # define schedstat_set(var, val)        do { } while (0)
  48 #endif
  49
  50 #ifdef CONFIG_SCHED_INFO
  51 static inline void sched_info_reset_dequeued(struct task_struct *t)
  52 {
  53         t->sched_info.last_queued = 0;
  54 }
  55
  56 /*
  57  * We are interested in knowing how long it was from the *first* time a
  58  * task was queued to the time that it finally hit a cpu, we call this routine
  59  * from dequeue_task() to account for possible rq->clock skew across cpus. The
  60  * delta taken on each cpu would annul the skew.
  61  */
  62 static inline void sched_info_dequeued(struct rq *rq, struct task_struct *t)
  63 {
  64         unsigned long long now = rq_clock(rq), delta = 0;
  65
  66         if (unlikely(sched_info_on()))
  67                 if (t->sched_info.last_queued)
  68                         delta = now - t->sched_info.last_queued;
  69         sched_info_reset_dequeued(t);
  70         t->sched_info.run_delay += delta;
  71
  72         rq_sched_info_dequeued(rq, delta);
  73 }
  74
  75 /*
  76  * Called when a task finally hits the cpu.  We can now calculate how
  77  * long it was waiting to run.  We also note when it began so that we
  78  * can keep stats on how long its timeslice is.
  79  */
  80 static void sched_info_arrive(struct rq *rq, struct task_struct *t)
  81 {
  82         unsigned long long now = rq_clock(rq), delta = 0;
  83
  84         if (t->sched_info.last_queued)
  85                 delta = now - t->sched_info.last_queued;
  86         sched_info_reset_dequeued(t);
  87         t->sched_info.run_delay += delta;
  88         t->sched_info.last_arrival = now;
  89         t->sched_info.pcount++;
  90
  91         rq_sched_info_arrive(rq, delta);
  92 }
  93
  94 /*
  95  * This function is only called from enqueue_task(), but also only updates
  96  * the timestamp if it is already not set.  It's assumed that
  97  * sched_info_dequeued() will clear that stamp when appropriate.
  98  */
  99 static inline void sched_info_queued(struct rq *rq, struct task_struct *t)
 100 {
 101         if (unlikely(sched_info_on()))
 102                 if (!t->sched_info.last_queued)
 103                         t->sched_info.last_queued = rq_clock(rq);
 104 }
 105
 106 /*
 107  * Called when a process ceases being the active-running process involuntarily
 108  * due, typically, to expiring its time slice (this may also be called when
 109  * switching to the idle task).  Now we can calculate how long we ran.
 110  * Also, if the process is still in the TASK_RUNNING state, call
 111  * sched_info_queued() to mark that it has now again started waiting on
 112  * the runqueue.
 113  */
 114 static inline void sched_info_depart(struct rq *rq, struct task_struct *t)
 115 {
 116         unsigned long long delta = rq_clock(rq) -
 117                                         t->sched_info.last_arrival;
 118
 119         rq_sched_info_depart(rq, delta);
 120
 121         if (t->state == TASK_RUNNING)
 122                 sched_info_queued(rq, t);
 123 }
 124
 125 /*
 126  * Called when tasks are switched involuntarily due, typically, to expiring
 127  * their time slice.  (This may also be called when switching to or from
 128  * the idle task.)  We are only called when prev != next.
 129  */
 130 static inline void
 131 __sched_info_switch(struct rq *rq,
 132                     struct task_struct *prev, struct task_struct *next)
 133 {
 134         /*
 135          * prev now departs the cpu.  It's not interesting to record
 136          * stats about how efficient we were at scheduling the idle
 137          * process, however.
 138          */
 139         if (prev != rq->idle)
 140                 sched_info_depart(rq, prev);
 141
 142         if (next != rq->idle)
 143                 sched_info_arrive(rq, next);
 144 }
 145 static inline void
 146 sched_info_switch(struct rq *rq,
 147                   struct task_struct *prev, struct task_struct *next)
 148 {
 149         if (unlikely(sched_info_on()))
 150                 __sched_info_switch(rq, prev, next);
 151 }
 152 #else
 153 #define sched_info_queued(rq, t)                do { } while (0)
 154 #define sched_info_reset_dequeued(t)    do { } while (0)
 155 #define sched_info_dequeued(rq, t)              do { } while (0)
 156 #define sched_info_depart(rq, t)                do { } while (0)
 157 #define sched_info_arrive(rq, next)             do { } while (0)
 158 #define sched_info_switch(rq, t, next)          do { } while (0)
 159 #endif /* CONFIG_SCHED_INFO */
 160
 161 /*
 162  * The following are functions that support scheduler-internal time accounting.
 163  * These functions are generally called at the timer tick.  None of this depends
 164  * on CONFIG_SCHEDSTATS.
 165  */
 166
 167 /**
 168  * cputimer_running - return true if cputimer is running
 169  *
 170  * @tsk:        Pointer to target task.
 171  */
 172 static inline bool cputimer_running(struct task_struct *tsk)
 173
 174 {
 175         struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
 176
 177         /* Check if cputimer isn't running. This is accessed without locking. */
 178         if (!READ_ONCE(cputimer->running))
 179                 return false;
 180
 181         /*
 182          * After we flush the task's sum_exec_runtime to sig->sum_sched_runtime
 183          * in __exit_signal(), we won't account to the signal struct further
 184          * cputime consumed by that task, even though the task can still be
 185          * ticking after __exit_signal().
 186          *
 187          * In order to keep a consistent behaviour between thread group cputime
 188          * and thread group cputimer accounting, lets also ignore the cputime
 189          * elapsing after __exit_signal() in any thread group timer running.
 190          *
 191          * This makes sure that POSIX CPU clocks and timers are synchronized, so
 192          * that a POSIX CPU timer won't expire while the corresponding POSIX CPU
 193          * clock delta is behind the expiring timer value.
 194          */
 195         if (unlikely(!tsk->sighand))
 196                 return false;
 197
 198         return true;
 199 }
 200
 201 /**
 202  * account_group_user_time - Maintain utime for a thread group.
 203  *
 204  * @tsk:        Pointer to task structure.
 205  * @cputime:    Time value by which to increment the utime field of the
 206  *              thread_group_cputime structure.
 207  *
 208  * If thread group time is being maintained, get the structure for the
 209  * running CPU and update the utime field there.
 210  */
 211 static inline void account_group_user_time(struct task_struct *tsk,
 212                                            cputime_t cputime)
 213 {
 214         struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
 215
 216         if (!cputimer_running(tsk))
 217                 return;
 218
 219         atomic64_add(cputime, &cputimer->cputime_atomic.utime);
 220 }
 221
 222 /**
 223  * account_group_system_time - Maintain stime for a thread group.
 224  *
 225  * @tsk:        Pointer to task structure.
 226  * @cputime:    Time value by which to increment the stime field of the
 227  *              thread_group_cputime structure.
 228  *
 229  * If thread group time is being maintained, get the structure for the
 230  * running CPU and update the stime field there.
 231  */
 232 static inline void account_group_system_time(struct task_struct *tsk,
 233                                              cputime_t cputime)
 234 {
 235         struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
 236
 237         if (!cputimer_running(tsk))
 238                 return;
 239
 240         atomic64_add(cputime, &cputimer->cputime_atomic.stime);
 241 }
 242
 243 /**
 244  * account_group_exec_runtime - Maintain exec runtime for a thread group.
 245  *
 246  * @tsk:        Pointer to task structure.
 247  * @ns:         Time value by which to increment the sum_exec_runtime field
 248  *              of the thread_group_cputime structure.
 249  *
 250  * If thread group time is being maintained, get the structure for the
 251  * running CPU and update the sum_exec_runtime field there.
 252  */
 253 static inline void account_group_exec_runtime(struct task_struct *tsk,
 254                                               unsigned long long ns)
 255 {
 256         struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
 257
 258         if (!cputimer_running(tsk))
 259                 return;
 260
 261         atomic64_add(ns, &cputimer->cputime_atomic.sum_exec_runtime);
 262 }