Scheduler API definition. More...

Detailed Description

Scheduler API definition.

Author: Kaspar Schleiser kaspa.nosp@m.r@sc.nosp@m.hleis.nosp@m.er.d.nosp@m.e; Hauke Petersen hauke.nosp@m..pet.nosp@m.ersen.nosp@m.@fu-.nosp@m.berli.nosp@m.n.de

Definition in file sched.h.

#include <stddef.h>
#include <inttypes.h>
#include "kernel_defines.h"
#include "native_sched.h"
#include "clist.h"

Include dependency graph for sched.h:

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Macros
#define	MAXTHREADS 0
	The maximum number of threads to be scheduled.

#define	KERNEL_PID_UNDEF 0
	Canonical identifier for an invalid PID.

#define	KERNEL_PID_FIRST (KERNEL_PID_UNDEF + 1)
	The first valid PID (inclusive).

#define	KERNEL_PID_LAST (KERNEL_PID_FIRST + MAXTHREADS - 1)
	The last valid PID (inclusive).

#define	PRIkernel_pid PRIi16
	Macro for printing formatter.

#define	SCHED_TEST_STACK 1
	Enables detection of stack overflows and measures stack usage when != 0.

#define	SCHED_PRIO_LEVELS 16
	The number of thread priority levels.

Typedefs
typedef int16_t	kernel_pid_t
	Unique process identifier.

typedef struct _thread	thread_t
	forward declaration for thread_t, defined in thread.h

typedef void(*	sched_callback_t) (kernel_pid_t active, kernel_pid_t next)
	Scheduler run callback.

Functions
static int	pid_is_valid (kernel_pid_t pid)
	Determine if the given pid is valid.

thread_t *	sched_run (void)
	Triggers the scheduler to schedule the next thread.

void	sched_set_status (thread_t *process, thread_status_t status)
	Set the status of the specified process.

void	sched_switch (uint16_t other_prio)
	Yield if appropriate.

NORETURN void	cpu_switch_context_exit (void)
	Call context switching at thread exit.

NORETURN void	sched_task_exit (void)
	Removes thread from scheduler and set status to STATUS_STOPPED.

void	sched_change_priority (thread_t *thread, uint8_t priority)
	Change the priority of the given thread.

void	sched_arch_idle (void)
	Set CPU to idle mode (CPU dependent)

void	sched_register_cb (sched_callback_t callback)
	Register a callback that will be called on every scheduler run.

static void	sched_runq_advance (uint8_t prio)
	Advance a runqueue.

void	sched_runq_callback (uint8_t prio)
	Scheduler runqueue (change) callback.

static int	sched_runq_is_empty (uint8_t prio)
	Tell if the number of threads in a runqueue is 0.

static int	sched_runq_exactly_one (uint8_t prio)
	Tell if the number of threads in a runqueue is 1.

static int	sched_runq_more_than_one (uint8_t prio)
	Tell if the number of threads in a runqueue greater than 1.

Variables
volatile unsigned int	sched_context_switch_request
	Flag indicating whether a context switch is necessary after handling an interrupt.

volatile thread_t *	sched_threads [KERNEL_PID_LAST+1]
	Thread table.

volatile int	sched_num_threads
	Number of running (non-terminated) threads.

clist_node_t	sched_runqueues [SCHED_PRIO_LEVELS]
	List of runqueues per priority level.

Helpers to work with thread states
#define	STATUS_ON_RUNQUEUE STATUS_RUNNING
	to check if on run queue: `st >= STATUS_ON_RUNQUEUE`

#define	STATUS_NOT_FOUND ((thread_status_t)~0)
	Describes an illegal thread status.

Thread states supported by RIOT
Keep in sync with OpenOCD src/rtos/riot.c
enum	thread_status_t { STATUS_STOPPED , STATUS_ZOMBIE , STATUS_SLEEPING , STATUS_MUTEX_BLOCKED , STATUS_RECEIVE_BLOCKED , STATUS_SEND_BLOCKED , STATUS_REPLY_BLOCKED , STATUS_FLAG_BLOCKED_ANY , STATUS_FLAG_BLOCKED_ALL , STATUS_MBOX_BLOCKED , STATUS_COND_BLOCKED , STATUS_RUNNING , STATUS_PENDING , STATUS_NUMOF }

Macros