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_enabled()            static_branch_unlikely(&sched_schedstats)
  33 # define schedstat_inc(rq, field)       do { if (schedstat_enabled()) { (rq)->field++; } } while (0)
  34 # define schedstat_add(rq, field, amt)  do { if (schedstat_enabled()) { (rq)->field += (amt); } } while (0)
  35 # define schedstat_set(var, val)        do { if (schedstat_enabled()) { var = (val); } } while (0)
  36 #else /* !CONFIG_SCHEDSTATS */
  37 static inline void
  38 rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
  39 {}
  40 static inline void
  41 rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
  42 {}
  43 static inline void
  44 rq_sched_info_depart(struct rq *rq, unsigned long long delta)
  45 {}
  46 # define schedstat_enabled()            0
  47 # define schedstat_inc(rq, field)       do { } while (0)
  48 # define schedstat_add(rq, field, amt)  do { } while (0)
  49 # define schedstat_set(var, val)        do { } while (0)
  50 #endif
  51
  52 #ifdef CONFIG_SCHED_INFO
  53 static inline void sched_info_reset_dequeued(struct task_struct *t)
  54 {
  55         t->sched_info.last_queued = 0;
  56 }
  57
  58 /*
  59  * We are interested in knowing how long it was from the *first* time a
  60  * task was queued to the time that it finally hit a cpu, we call this routine
  61  * from dequeue_task() to account for possible rq->clock skew across cpus. The
  62  * delta taken on each cpu would annul the skew.
  63  */
  64 static inline void sched_info_dequeued(struct rq *rq, struct task_struct *t)
  65 {
  66         unsigned long long now = rq_clock(rq), delta = 0;
  67
  68         if (unlikely(sched_info_on()))
  69                 if (t->sched_info.last_queued)
  70                         delta = now - t->sched_info.last_queued;
  71         sched_info_reset_dequeued(t);
  72         t->sched_info.run_delay += delta;
  73
  74         rq_sched_info_dequeued(rq, delta);
  75 }
  76
  77 /*
  78  * Called when a task finally hits the cpu.  We can now calculate how
  79  * long it was waiting to run.  We also note when it began so that we
  80  * can keep stats on how long its timeslice is.
  81  */
  82 static void sched_info_arrive(struct rq *rq, struct task_struct *t)
  83 {
  84         unsigned long long now = rq_clock(rq), delta = 0;
  85
  86         if (t->sched_info.last_queued)
  87                 delta = now - t->sched_info.last_queued;
  88         sched_info_reset_dequeued(t);
  89         t->sched_info.run_delay += delta;
  90         t->sched_info.last_arrival = now;
  91         t->sched_info.pcount++;
  92
  93         rq_sched_info_arrive(rq, delta);
  94 }
  95
  96 /*
  97  * This function is only called from enqueue_task(), but also only updates
  98  * the timestamp if it is already not set.  It's assumed that
  99  * sched_info_dequeued() will clear that stamp when appropriate.
 100  */
 101 static inline void sched_info_queued(struct rq *rq, struct task_struct *t)
 102 {
 103         if (unlikely(sched_info_on()))
 104                 if (!t->sched_info.last_queued)
 105                         t->sched_info.last_queued = rq_clock(rq);
 106 }
 107
 108 /*
 109  * Called when a process ceases being the active-running process involuntarily
 110  * due, typically, to expiring its time slice (this may also be called when
 111  * switching to the idle task).  Now we can calculate how long we ran.
 112  * Also, if the process is still in the TASK_RUNNING state, call
 113  * sched_info_queued() to mark that it has now again started waiting on
 114  * the runqueue.
 115  */
 116 static inline void sched_info_depart(struct rq *rq, struct task_struct *t)
 117 {
 118         unsigned long long delta = rq_clock(rq) -
 119                                         t->sched_info.last_arrival;
 120
 121         rq_sched_info_depart(rq, delta);
 122
 123         if (t->state == TASK_RUNNING)
 124                 sched_info_queued(rq, t);
 125 }
 126
 127 /*
 128  * Called when tasks are switched involuntarily due, typically, to expiring
 129  * their time slice.  (This may also be called when switching to or from
 130  * the idle task.)  We are only called when prev != next.
 131  */
 132 static inline void
 133 __sched_info_switch(struct rq *rq,
 134                     struct task_struct *prev, struct task_struct *next)
 135 {
 136         /*
 137          * prev now departs the cpu.  It's not interesting to record
 138          * stats about how efficient we were at scheduling the idle
 139          * process, however.
 140          */
 141         if (prev != rq->idle)
 142                 sched_info_depart(rq, prev);
 143
 144         if (next != rq->idle)
 145                 sched_info_arrive(rq, next);
 146 }
 147 static inline void
 148 sched_info_switch(struct rq *rq,
 149                   struct task_struct *prev, struct task_struct *next)
 150 {
 151         if (unlikely(sched_info_on()))
 152                 __sched_info_switch(rq, prev, next);
 153 }
 154 #else
 155 #define sched_info_queued(rq, t)                do { } while (0)
 156 #define sched_info_reset_dequeued(t)    do { } while (0)
 157 #define sched_info_dequeued(rq, t)              do { } while (0)
 158 #define sched_info_depart(rq, t)                do { } while (0)
 159 #define sched_info_arrive(rq, next)             do { } while (0)
 160 #define sched_info_switch(rq, t, next)          do { } while (0)
 161 #endif /* CONFIG_SCHED_INFO */
 162
 163 /*
 164  * The following are functions that support scheduler-internal time accounting.
 165  * These functions are generally called at the timer tick.  None of this depends
 166  * on CONFIG_SCHEDSTATS.
 167  */
 168
 169 /**
 170  * cputimer_running - return true if cputimer is running
 171  *
 172  * @tsk:        Pointer to target task.
 173  */
 174 static inline bool cputimer_running(struct task_struct *tsk)
 175
 176 {
 177         struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
 178
 179         /* Check if cputimer isn't running. This is accessed without locking. */
 180         if (!READ_ONCE(cputimer->running))
 181                 return false;
 182
 183         /*
 184          * After we flush the task's sum_exec_runtime to sig->sum_sched_runtime
 185          * in __exit_signal(), we won't account to the signal struct further
 186          * cputime consumed by that task, even though the task can still be
 187          * ticking after __exit_signal().
 188          *
 189          * In order to keep a consistent behaviour between thread group cputime
 190          * and thread group cputimer accounting, lets also ignore the cputime
 191          * elapsing after __exit_signal() in any thread group timer running.
 192          *
 193          * This makes sure that POSIX CPU clocks and timers are synchronized, so
 194          * that a POSIX CPU timer won't expire while the corresponding POSIX CPU
 195          * clock delta is behind the expiring timer value.
 196          */
 197         if (unlikely(!tsk->sighand))
 198                 return false;
 199
 200         return true;
 201 }
 202
 203 /**
 204  * account_group_user_time - Maintain utime for a thread group.
 205  *
 206  * @tsk:        Pointer to task structure.
 207  * @cputime:    Time value by which to increment the utime field of the
 208  *              thread_group_cputime structure.
 209  *
 210  * If thread group time is being maintained, get the structure for the
 211  * running CPU and update the utime field there.
 212  */
 213 static inline void account_group_user_time(struct task_struct *tsk,
 214                                            cputime_t cputime)
 215 {
 216         struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
 217
 218         if (!cputimer_running(tsk))
 219                 return;
 220
 221         atomic64_add(cputime, &cputimer->cputime_atomic.utime);
 222 }
 223
 224 /**
 225  * account_group_system_time - Maintain stime for a thread group.
 226  *
 227  * @tsk:        Pointer to task structure.
 228  * @cputime:    Time value by which to increment the stime field of the
 229  *              thread_group_cputime structure.
 230  *
 231  * If thread group time is being maintained, get the structure for the
 232  * running CPU and update the stime field there.
 233  */
 234 static inline void account_group_system_time(struct task_struct *tsk,
 235                                              cputime_t cputime)
 236 {
 237         struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
 238
 239         if (!cputimer_running(tsk))
 240                 return;
 241
 242         atomic64_add(cputime, &cputimer->cputime_atomic.stime);
 243 }
 244
 245 /**
 246  * account_group_exec_runtime - Maintain exec runtime for a thread group.
 247  *
 248  * @tsk:        Pointer to task structure.
 249  * @ns:         Time value by which to increment the sum_exec_runtime field
 250  *              of the thread_group_cputime structure.
 251  *
 252  * If thread group time is being maintained, get the structure for the
 253  * running CPU and update the sum_exec_runtime field there.
 254  */
 255 static inline void account_group_exec_runtime(struct task_struct *tsk,
 256                                               unsigned long long ns)
 257 {
 258         struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
 259
 260         if (!cputimer_running(tsk))
 261                 return;
 262
 263         atomic64_add(ns, &cputimer->cputime_atomic.sum_exec_runtime);
 264 }