diff options
Diffstat (limited to 'os/kernel/src/chschd.c')
| -rw-r--r-- | os/kernel/src/chschd.c | 111 |
1 files changed, 54 insertions, 57 deletions
diff --git a/os/kernel/src/chschd.c b/os/kernel/src/chschd.c index 5b4d18133..5bd016226 100644 --- a/os/kernel/src/chschd.c +++ b/os/kernel/src/chschd.c @@ -18,8 +18,9 @@ */ /** - * @file chschd.c - * @brief Scheduler code. + * @file chschd.c + * @brief Scheduler code. + * * @addtogroup scheduler * @{ */ @@ -27,14 +28,13 @@ #include "ch.h" /** - * @brief Ready list header. + * @brief Ready list header. */ ReadyList rlist; /** - * @brief Scheduler initialization. - * - * @note Internally invoked by the @p chSysInit(). + * @brief Scheduler initialization. + * @note Internally invoked by the @p chSysInit(), not an API. */ void scheduler_init(void) { @@ -49,12 +49,12 @@ void scheduler_init(void) { } /** - * @brief Inserts a thread in the Ready List. + * @brief Inserts a thread in the Ready List. + * @note The function does not reschedule, the @p chSchRescheduleS() should + * be called soon after. * - * @param[in] tp the Thread to be made ready - * @return The Thread pointer. - * @note The function does not reschedule, the @p chSchRescheduleS() should - * be called soon after. + * @param[in] tp the Thread to be made ready + * @return The Thread pointer. */ #if CH_OPTIMIZE_SPEED /* NOTE: it is inlined in this module only.*/ @@ -76,11 +76,11 @@ Thread *chSchReadyI(Thread *tp) { } /** - * @brief Puts the current thread to sleep into the specified state. + * @brief Puts the current thread to sleep into the specified state. * @details The thread goes into a sleeping state. The @ref thread_states are * described into @p threads.h. * - * @param[in] newstate the new thread state + * @param[in] newstate the new thread state */ void chSchGoSleepS(tstate_t newstate) { Thread *otp; @@ -121,24 +121,24 @@ static void wakeup(void *p) { } /** - * @brief Puts the current thread to sleep into the specified state with - * timeout specification. + * @brief Puts the current thread to sleep into the specified state with + * timeout specification. * @details The thread goes into a sleeping state, if it is not awakened * explicitly within the specified timeout then it is forcibly * awakened with a @p RDY_TIMEOUT low level message. The @ref * thread_states are described into @p threads.h. * - * @param[in] newstate the new thread state - * @param[in] time the number of ticks before the operation timeouts, the - * special values are handled as follow: - * - @a TIME_INFINITE the thread enters an infinite sleep - * state, this is equivalent to invoking @p chSchGoSleepS() - * but, of course, less efficient. - * - @a TIME_IMMEDIATE this value is accepted but interpreted - * as a normal time specification not as an immediate timeout - * specification. - * . - * @return The wakeup message. + * @param[in] newstate the new thread state + * @param[in] time the number of ticks before the operation timeouts, the + * special values are handled as follow: + * - @a TIME_INFINITE the thread enters an infinite sleep + * state, this is equivalent to invoking + * @p chSchGoSleepS() but, of course, less efficient. + * - @a TIME_IMMEDIATE this value is accepted but + * interpreted as a normal time specification not as an + * immediate timeout specification. + * . + * @return The wakeup message. * @retval RDY_TIMEOUT if a timeout occurs. */ msg_t chSchGoSleepTimeoutS(tstate_t newstate, systime_t time) { @@ -157,24 +157,25 @@ msg_t chSchGoSleepTimeoutS(tstate_t newstate, systime_t time) { } /** - * @brief Wakes up a thread. + * @brief Wakes up a thread. * @details The thread is inserted into the ready list or immediately made * running depending on its relative priority compared to the current * thread. + * @note It is equivalent to a @p chSchReadyI() followed by a + * @p chSchRescheduleS() but much more efficient. + * @note The function assumes that the current thread has the highest + * priority. * - * @param[in] ntp the Thread to be made ready - * @param[in] msg message to the awakened thread - * @note It is equivalent to a @p chSchReadyI() followed by a - * @p chSchRescheduleS() but much more efficient. - * @note The function assumes that the current thread has the highest priority + * @param[in] ntp the Thread to be made ready + * @param[in] msg message to the awakened thread */ void chSchWakeupS(Thread *ntp, msg_t msg) { ntp->p_u.rdymsg = msg; /* If the waken thread has a not-greater priority than the current - * one then it is just inserted in the ready list else it made - * running immediately and the invoking thread goes in the ready - * list instead.*/ + one then it is just inserted in the ready list else it made + running immediately and the invoking thread goes in the ready + list instead.*/ if (ntp->p_prio <= currp->p_prio) chSchReadyI(ntp); else { @@ -190,10 +191,9 @@ void chSchWakeupS(Thread *ntp, msg_t msg) { } /** - * @brief Switches to the first thread on the runnable queue. - * - * @note It is intended to be called if @p chSchRescRequiredI() evaluates to - * @p TRUE. + * @brief Switches to the first thread on the runnable queue. + * @note It is intended to be called if @p chSchRescRequiredI() evaluates + * to @p TRUE. */ void chSchDoRescheduleI(void) { @@ -209,7 +209,7 @@ void chSchDoRescheduleI(void) { } /** - * @brief Performs a reschedulation if a higher priority thread is runnable. + * @brief Performs a reschedulation if a higher priority thread is runnable. * @details If a thread with a higher priority than the current thread is in * the ready list then make the higher priority thread running. */ @@ -220,34 +220,33 @@ void chSchRescheduleS(void) { } /** - * @brief Evaluates if a reschedulation is required. + * @brief Evaluates if a reschedulation is required. * @details The decision is taken by comparing the relative priorities and * depending on the state of the round robin timeout counter. + * @note This function is meant to be used in the timer interrupt handler + * where @p chVTDoTickI() is invoked. * - * @retval TRUE if there is a thread that should go in running state. - * @retval FALSE if a reschedulation is not required. - * - * @note This function is meant to be used in the timer interrupt handler - * where @p chVTDoTickI() is invoked. + * @retval TRUE if there is a thread that should go in running state. + * @retval FALSE if a reschedulation is not required. */ bool_t chSchIsRescRequiredExI(void) { tprio_t p1 = firstprio(&rlist.r_queue); tprio_t p2 = currp->p_prio; #if CH_TIME_QUANTUM > 0 /* If the running thread has not reached its time quantum, reschedule only - * if the first thread on the ready queue has a higher priority. - * Otherwise, if the running thread has used up its time quantum, reschedule - * if the first thread on the ready queue has equal or higher priority.*/ + if the first thread on the ready queue has a higher priority. + Otherwise, if the running thread has used up its time quantum, reschedule + if the first thread on the ready queue has equal or higher priority.*/ return rlist.r_preempt ? p1 > p2 : p1 >= p2; #else - /* If the round robin feature is not enabled then performs a simpler - * comparison.*/ + /* If the round robin preemption feature is not enabled then performs a + simpler comparison.*/ return p1 > p2; #endif } /** - * @brief Yields the time slot. + * @brief Yields the time slot. * @details Yields the CPU control to the next thread in the ready list with * equal priority, if any. */ @@ -257,11 +256,9 @@ void chSchDoYieldS(void) { Thread *cp = (Thread *)&rlist.r_queue; Thread *otp = currp; - /* - * Note, the following insertion code works because we know that on the - * ready list there is at least one thread with priority equal or higher - * than the current one. - */ + /* Note, the following insertion code works because we know that on the + ready list there is at least one thread with priority equal or higher + than the current one.*/ otp->p_state = THD_STATE_READY; do { cp = cp->p_prev; |