Collaboration diagram for Scheduler:

Description

This module provides the default portable scheduler code, scheduler functions can be individually captured by the port layer in order to provide architecture optimized equivalents. When a function is captured its default code is not built into the OS image, the optimized version is included instead.

Data Structures
struct	ReadyList
	Ready list header. More...
Defines
#define	RDY_OK 0
	Default thread wakeup low level message.
#define	RDY_TIMEOUT -1
	Low level message sent to a thread awakened by a timeout.
#define	RDY_RESET -2
	Low level message sent to a thread awakened by a reset operation.
#define	NOPRIO 0
	Ready list header priority.
#define	IDLEPRIO 1
	Idle thread priority.
#define	LOWPRIO 2
	Lowest user priority.
#define	NORMALPRIO 64
	Normal user priority.
#define	HIGHPRIO 127
	Highest user priority.
#define	ABSPRIO 255
	Greatest possible priority.
#define	TIME_IMMEDIATE ((systime_t)-1)
	Zero time specification for some syscalls with a timeout specification.
#define	TIME_INFINITE ((systime_t)0)
	Infinite time specification for all the syscalls with a timeout specification.
#define	firstprio(rlp) ((rlp)->p_next->p_prio)
	Returns the priority of the first thread on the given ready list.
#define	currp rlist.r_current
	Current thread pointer access macro.
#define	setcurrp(tp) (currp = (tp))
	Current thread pointer change macro.
#define	chSchIsRescRequiredI() (firstprio(&rlist.r_queue) > currp->p_prio)
	Determines if the current thread must reschedule.
#define	chSchCanYieldS() (firstprio(&rlist.r_queue) >= currp->p_prio)
	Determines if yielding is possible.
#define	chSchDoYieldS()
	Yields the time slot.
Functions
void	scheduler_init (void)
	Scheduler initialization.
Thread *	chSchReadyI (Thread *tp)
	Inserts a thread in the Ready List.
void	chSchGoSleepS (tstate_t newstate)
	Puts the current thread to sleep into the specified state.
msg_t	chSchGoSleepTimeoutS (tstate_t newstate, systime_t time)
	Puts the current thread to sleep into the specified state with timeout specification.
void	chSchWakeupS (Thread *ntp, msg_t msg)
	Wakes up a thread.
void	chSchDoRescheduleI (void)
	Switches to the first thread on the runnable queue.
void	chSchRescheduleS (void)
	Performs a reschedule if a higher priority thread is runnable.
bool_t	chSchIsRescRequiredExI (void)
	Evaluates if a reschedule is required.
Variables
ReadyList	rlist
	Ready list header.

Define Documentation

#define RDY_OK 0

Default thread wakeup low level message.

Definition at line 39 of file chschd.h.

Referenced by canReceive(), canTransmit(), chCondSignal(), chEvtWaitAllTimeout(), chEvtWaitAnyTimeout(), chEvtWaitOneTimeout(), chIQGetTimeout(), chIQReadTimeout(), chMBFetchS(), chMBPostAheadS(), chMBPostS(), chMtxUnlock(), chOQPutTimeout(), chOQWriteTimeout(), chSemSignal(), chThdCreateFromHeap(), chThdCreateFromMemoryPool(), chThdCreateStatic(), chThdResume(), macWaitReceiveDescriptor(), and macWaitTransmitDescriptor().

#define RDY_TIMEOUT -1

Low level message sent to a thread awakened by a timeout.

Definition at line 41 of file chschd.h.

Referenced by adcWaitConversion(), chCondWaitTimeoutS(), macWaitReceiveDescriptor(), and macWaitTransmitDescriptor().

#define RDY_RESET -2

Low level message sent to a thread awakened by a reset operation.

Definition at line 43 of file chschd.h.

#define NOPRIO 0

Ready list header priority.

Definition at line 45 of file chschd.h.

#define IDLEPRIO 1

Idle thread priority.

Definition at line 46 of file chschd.h.

Referenced by chSysInit().

#define LOWPRIO 2

Lowest user priority.

Definition at line 47 of file chschd.h.

Referenced by chThdSetPriority().

#define NORMALPRIO 64

Normal user priority.

Definition at line 48 of file chschd.h.

Referenced by chSysInit().

#define HIGHPRIO 127

Highest user priority.

Definition at line 49 of file chschd.h.

Referenced by chThdCreateI(), and chThdSetPriority().

#define ABSPRIO 255

Greatest possible priority.

Definition at line 50 of file chschd.h.

#define TIME_IMMEDIATE ((systime_t)-1)

Zero time specification for some syscalls with a timeout specification.

Note:: Not all functions accept TIME_IMMEDIATE as timeout parameter, see the specific function documentation.

Definition at line 58 of file chschd.h.

Referenced by chEvtWaitAllTimeout(), chEvtWaitAnyTimeout(), chEvtWaitOneTimeout(), and chSemWaitTimeoutS().

#define TIME_INFINITE ((systime_t)0)

Infinite time specification for all the syscalls with a timeout specification.

Definition at line 64 of file chschd.h.

Referenced by chSchGoSleepTimeoutS(), chThdSleep(), chVTSetI(), macWaitReceiveDescriptor(), and macWaitTransmitDescriptor().

#define firstprio ( rlp ) ((rlp)->p_next->p_prio)

Returns the priority of the first thread on the given ready list.

Definition at line 69 of file chschd.h.

Referenced by chSchIsRescRequiredExI().

#define currp rlist.r_current

Current thread pointer access macro.

Note:: This macro is not meant to be used in the application code but only from within the kernel, use the chThdSelf() API instead.; It is forbidden to use this macro in order to change the pointer (currp = something), use setcurrp() instead.

Definition at line 111 of file chschd.h.

Referenced by chCondWaitTimeoutS(), chDbgTrace(), chEvtClear(), chEvtPend(), chMsgGet(), chMsgRelease(), chMsgWait(), chMtxTryLockS(), chSchDoRescheduleI(), chSchGoSleepS(), chSchGoSleepTimeoutS(), chSchIsRescRequiredExI(), chSchWakeupS(), chSemWaitS(), chSemWaitTimeoutS(), chSysInit(), chSysTimerHandlerI(), chThdSetPriority(), chThdWait(), and chibios_rt::BaseThread::IsPendingMessage().

#define setcurrp ( tp ) (currp = (tp))

Current thread pointer change macro.

Note:: This macro is not meant to be used in the application code but only from within the kernel.

Definition at line 123 of file chschd.h.

Referenced by chSchDoRescheduleI(), chSchGoSleepS(), chSchWakeupS(), and chSysInit().

#define chSchIsRescRequiredI ( ) (firstprio(&rlist.r_queue) > currp->p_prio)

Determines if the current thread must reschedule.

This function returns TRUE if there is a ready thread with higher priority.

Definition at line 164 of file chschd.h.

Referenced by chSchRescheduleS().

#define chSchCanYieldS ( ) (firstprio(&rlist.r_queue) >= currp->p_prio)

Determines if yielding is possible.

This function returns TRUE if there is a ready thread with equal or higher priority.

Definition at line 173 of file chschd.h.

#define chSchDoYieldS ( )

Value:

{                                                   \
  if (chSchCanYieldS())                                                     \
    chSchDoRescheduleI();                                                   \
}

Yields the time slot.

Yields the CPU control to the next thread in the ready list with equal or higher priority, if any.

Definition at line 182 of file chschd.h.

Referenced by chThdYield().

Function Documentation

void scheduler_init ( void )

Scheduler initialization.

Note:: Internally invoked by the chSysInit(), not an API.

Definition at line 53 of file chschd.c.

References queue_init, ReadyList::r_newer, ReadyList::r_older, ReadyList::r_prio, and ReadyList::r_queue.

Referenced by chSysInit().

Thread * chSchReadyI ( Thread * tp )

Inserts a thread in the Ready List.

Note:: The function does not reschedule, the chSchRescheduleS() should be called soon after.

Parameters:

[in] tp the Thread to be made ready

Returns:: The Thread pointer.

Definition at line 78 of file chschd.c.

References Thread::p_next, Thread::p_state, and ReadyList::r_queue.

Referenced by chCondBroadcastI(), chCondSignalI(), chEvtSignalI(), chMsgSend(), chMtxLockS(), chMtxUnlockAll(), chMtxUnlockS(), chSchDoRescheduleI(), chSchWakeupS(), chSemResetI(), chSemSignalI(), chSemSignalWait(), and chThdExit().

void chSchGoSleepS ( tstate_t newstate )

Puts the current thread to sleep into the specified state.

The thread goes into a sleeping state. The Threads States are described into threads.h.

Parameters:

[in] newstate the new thread state

Definition at line 103 of file chschd.c.

References chDbgTrace(), chSysSwitchI, currp, fifo_remove(), ReadyList::r_queue, and setcurrp.

Referenced by chCondWaitS(), chEvtWaitAll(), chEvtWaitAny(), chEvtWaitOne(), chMsgSend(), chMsgWait(), chMtxLockS(), chSchGoSleepTimeoutS(), chSemSignalWait(), chSemWaitS(), chThdExit(), and chThdWait().

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msg_t chSchGoSleepTimeoutS	(	tstate_t	newstate,
		systime_t	time
	)

Puts the current thread to sleep into the specified state with timeout specification.

The thread goes into a sleeping state, if it is not awakened explicitly within the specified timeout then it is forcibly awakened with a RDY_TIMEOUT low level message. The Threads States are described into threads.h.

Parameters:

[in] newstate the new thread state

[in]

time

the number of ticks before the operation timeouts, the special values are handled as follow:

TIME_INFINITE the thread enters an infinite sleep state, this is equivalent to invoking chSchGoSleepS() but, of course, less efficient.
TIME_IMMEDIATE this value is accepted but interpreted as a normal time specification not as an immediate timeout specification.

Returns:: The wakeup message.

Return values:

RDY_TIMEOUT

if a timeout occurs.

Definition at line 167 of file chschd.c.

References chSchGoSleepS(), chVTIsArmedI, chVTResetI(), chVTSetI(), currp, and TIME_INFINITE.

Referenced by chCondWaitTimeoutS(), chEvtWaitAllTimeout(), chEvtWaitAnyTimeout(), chEvtWaitOneTimeout(), and chSemWaitTimeoutS().

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void chSchWakeupS	(	Thread *	ntp,
		msg_t	msg
	)

Wakes up a thread.

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 chSchReadyI() followed by a chSchRescheduleS() but much more efficient.; The function assumes that the current thread has the highest priority.

Parameters: