Scheduler structures and functions. More...

Macros
#define	__DEBUG_HEADER__ "[SCHED ]"
	Change header.

#define	__DEBUG_LEVEL__ LOGLEVEL_NOTICE
	Set log level.

#define	RETURN_PROCESS_ATTR_OR_EPERM(attr)
	Returns the attributes of the runnign process. More...

#define	FAIL_ON_INV_ID(id) if (id < 0) { return -EINVAL; }
	Checks the given ID.

#define	FAIL_ON_INV_ID_OR_PROC(id)
	Checks the ID, and if there is a running process. More...

#define	IF_PRIVILEGED_SET_ALL_AND_RETURN(attr)
	If the process is ROOT, set the attribute and return 0. More...

#define	IF_RESET_SET_AND_RETURN(attr)
	Checks the attributes, resets them, and returns 0. More...

#define	SET_IF_PRIVILEGED_OR_FAIL(attr)
	If the process is ROOT set the attribute, otherwise return failure. More...

Functions
void	enter_userspace (uintptr_t location, uintptr_t stack)
	Assembly function setting the kernel stack to jump into location in Ring 3 mode (USER mode). More...

void	scheduler_initialize (void)
	Initialize the scheduler.

uint32_t	scheduler_getpid (void)
	Returns a non-decreasing unique process id. More...

task_struct *	scheduler_get_current_process (void)
	Returns the pointer to the current active process. More...

time_t	scheduler_get_maximum_vruntime (void)
	Returns the maximum vruntime of all the processes in running state. More...

size_t	scheduler_get_active_processes (void)
	Returns the number of active processes. More...

task_struct *	scheduler_get_running_process (pid_t pid)
	Returns a pointer to the process with the given pid. More...

void	scheduler_enqueue_task (task_struct *process)
	Activate the given process. More...

void	scheduler_dequeue_task (task_struct *process)
	Removes the given process from the queue. More...

void	scheduler_run (pt_regs *f)
	The RR implementation of the scheduler. More...

void	scheduler_store_context (pt_regs f, task_struct process)
	Values from pt_regs to task_struct process. More...

void	scheduler_restore_context (task_struct process, pt_regs f)
	Values from task_struct process to pt_regs. More...

void	scheduler_enter_user_jmp (uintptr_t location, uintptr_t stack)
	Switch CPU to user mode and start running that given process. More...

static int	try_to_wake_up (task_struct *process, unsigned mode, int sync)
	Awakens a sleeping process. More...

int	default_wake_function (wait_queue_entry_t *wait, unsigned mode, int sync)
	The default wake function, a wrapper for try_to_wake_up. More...

wait_queue_entry_t *	sleep_on (wait_queue_head_t *wq)
	Sets the state of the current process to TASK_UNINTERRUPTIBLE and inserts it into the specified wait queue. More...

int	is_orphaned_pgrp (pid_t pgid)
	Returns 1 if the given group is orphaned, the session leader of the group is no longer alive. More...

pid_t	sys_getpid (void)
	Returns the process ID (PID) of the calling process. More...

pid_t	sys_getsid (pid_t pid)
	Return session id of the given process. If pid == 0 return the SID of the calling process If pid != 0 return the SID corresponding to the process having identifier == pid. More...

pid_t	sys_setsid (void)
	creates a new session if the calling process is not a process group leader. The calling process is the leader of the new session (i.e., its session ID is made the same as its process ID). The calling process also becomes the process group leader of a new process group in the session (i.e., its process group ID is made the same as its process ID). More...

pid_t	sys_getpgid (pid_t pid)
	returns the Process Group ID (PGID) of the process specified by pid. If pid is zero, the process ID of the calling process is used. More...

int	sys_setpgid (pid_t pid, pid_t pgid)
	Sets the Process Group ID (PGID) of the process specified by pid. If pid is zero, the process ID of the calling process is used. More...

uid_t	sys_getuid (void)
	Returns the real User ID (UID) of the calling process. More...

uid_t	sys_geteuid (void)
	Returns the effective User ID (UID) of the calling process. More...

gid_t	sys_getgid (void)
	returns the real group ID of the calling process. More...

gid_t	sys_getegid (void)
	returns the effective group ID of the calling process. More...

int	sys_setuid (uid_t uid)
	Tries to set the User ID (UID) of the calling process. More...

int	sys_setgid (gid_t gid)
	sets the group ID of the calling process. More...

int	sys_setreuid (uid_t ruid, uid_t euid)
	Set the real and effective User ID (UID) of the calling process. More...

int	sys_setregid (gid_t rgid, gid_t egid)
	sets the real and effective group ID of the calling process. More...

pid_t	sys_getppid (void)
	Returns the parent process ID (PPID) of the calling process. More...

int	sys_nice (int increment)
	Adds the increment to the priority value of the task. More...

pid_t	sys_waitpid (pid_t pid, int *status, int options)
	Suspends execution of the calling thread until a child specified by pid argument has changed state. More...

void	do_exit (int exit_code)
	Exit the current process with status. More...

void	sys_exit (int exit_code)

int	sys_sched_setparam (pid_t pid, const sched_param_t *param)
	Set new scheduling settings for the given process. More...

int	sys_sched_getparam (pid_t pid, sched_param_t *param)
	Gets the scheduling settings for the given process. More...

static int	__response_time_analysis (void)
	Performs the response time analysis for the current list of periodic processes. More...

static double	__compute_utilization_factor (void)
	Computes the total utilization factor. More...

int	sys_waitperiod (void)
	Puts the process on wait until its next period starts. More...

Variables
runqueue_t	runqueue
	The list of processes.

Detailed Description

Scheduler structures and functions.

Copyright: (c) 2014-2024 This file is distributed under the MIT License. See LICENSE.md for details.

Macro Definition Documentation

◆ FAIL_ON_INV_ID_OR_PROC

#define FAIL_ON_INV_ID_OR_PROC ( id )

Value:

FAIL_ON_INV_ID(id) \

if (!runqueue.curr) { return -EPERM; }

EPERM

#define EPERM

Operation not permitted.

Definition: errno.h:13

FAIL_ON_INV_ID

#define FAIL_ON_INV_ID(id)

Checks the given ID.

Definition: scheduler.c:403

runqueue

runqueue_t runqueue

The list of processes.

Definition: scheduler.c:31

runqueue_t::curr

task_struct * curr

The current running process.

Definition: scheduler.h:21

Checks the ID, and if there is a running process.

◆ IF_PRIVILEGED_SET_ALL_AND_RETURN

#define IF_PRIVILEGED_SET_ALL_AND_RETURN ( attr )

Value:

    if (runqueue.curr->uid == 0) {                           \
        runqueue.curr->r##attr = runqueue.curr->attr = attr; \
        return 0;                                            \
    }

If the process is ROOT, set the attribute and return 0.

◆ IF_RESET_SET_AND_RETURN

#define IF_RESET_SET_AND_RETURN ( attr )

Value:

    if (runqueue.curr->r##attr == attr) { \
        runqueue.curr->attr = attr;       \
        return 0;                         \
    }

Checks the attributes, resets them, and returns 0.

◆ RETURN_PROCESS_ATTR_OR_EPERM

#define RETURN_PROCESS_ATTR_OR_EPERM ( attr )

Value:

if (runqueue.curr) { return runqueue.curr->attr; } \

return -EPERM;

Returns the attributes of the runnign process.

◆ SET_IF_PRIVILEGED_OR_FAIL

#define SET_IF_PRIVILEGED_OR_FAIL ( attr )

Value:

    if (runqueue.curr->uid == 0) {      \
        runqueue.curr->attr = attr;     \
    } else {                            \
        return -EPERM;                  \
    }

If the process is ROOT set the attribute, otherwise return failure.

Function Documentation

◆ __compute_utilization_factor()

static double __compute_utilization_factor ( void )

inlinestatic

Computes the total utilization factor.

Returns: the utilization factor.

◆ __response_time_analysis()

static int __response_time_analysis ( void )

static

Performs the response time analysis for the current list of periodic processes.

Returns: 1 if scheduling periodic processes is feasible, 0 otherwise.

◆ default_wake_function()

int default_wake_function	(	wait_queue_entry_t *	wait,
		unsigned	mode,
		int	sync
	)

The default wake function, a wrapper for try_to_wake_up.

Parameters

wait	The pointer to the wait queue.
mode	The type of wait (TASK_INTERRUPTIBLE or TASK_UNINTERRUPTIBLE).
sync	Specifies if the wakeup should be synchronous.

Returns: 1 on success, 0 on failure.

◆ do_exit()

void do_exit ( int status )

Exit the current process with status.

Parameters

status The exit status of the current process

◆ enter_userspace()

void enter_userspace	(	uintptr_t	location,
		uintptr_t	stack
	)

Assembly function setting the kernel stack to jump into location in Ring 3 mode (USER mode).

Parameters

location	The location where to jump.
stack	The stack to use.

◆ is_orphaned_pgrp()

int is_orphaned_pgrp ( pid_t gid )

Returns 1 if the given group is orphaned, the session leader of the group is no longer alive.

Parameters

gid	ID of the group

Returns: 1 if the group is orphan, 0 otherwise.

◆ scheduler_dequeue_task()

void scheduler_dequeue_task ( task_struct * process )

Removes the given process from the queue.

Parameters

process Process that has to be activated.

◆ scheduler_enqueue_task()

void scheduler_enqueue_task ( task_struct * process )

Activate the given process.

Parameters

process Process that has to be activated.

◆ scheduler_enter_user_jmp()

void scheduler_enter_user_jmp	(	uintptr_t	location,
		uintptr_t	stack
	)

Switch CPU to user mode and start running that given process.

Parameters

location	The instruction pointer of the process we are starting.
stack	Address of the stack of that process.

◆ scheduler_get_active_processes()

size_t scheduler_get_active_processes ( void )

Returns the number of active processes.

Returns: Number of processes.

◆ scheduler_get_current_process()

task_struct* scheduler_get_current_process ( void )

Returns the pointer to the current active process.

Returns: Pointer to the current process.

◆ scheduler_get_maximum_vruntime()

time_t scheduler_get_maximum_vruntime ( void )

Returns the maximum vruntime of all the processes in running state.

Returns: A maximum vruntime value.

◆ scheduler_get_running_process()

task_struct* scheduler_get_running_process ( pid_t pid )

Returns a pointer to the process with the given pid.

Parameters

pid	The pid of the process we are looking for.

Returns: Pointer to the process, or NULL if we cannot find it.

◆ scheduler_getpid()

uint32_t scheduler_getpid ( void )

Returns a non-decreasing unique process id.

Returns: Process identifier (PID).

The current unused PID.

◆ scheduler_restore_context()

void scheduler_restore_context	(	task_struct *	process,
		pt_regs *	f
	)

Values from task_struct process to pt_regs.

Parameters

process	The process for which we are restoring the registers in CPU .
f	The set of registers we are restoring.

◆ scheduler_run()

void scheduler_run ( pt_regs * f )

The RR implementation of the scheduler.

Parameters

f	The context of the process.

◆ scheduler_store_context()

void scheduler_store_context	(	pt_regs *	f,
		task_struct *	process
	)

Values from pt_regs to task_struct process.

Parameters

f	The set of registers we are saving.
process	The process for which we are saving the CPU registers status.

◆ sleep_on()

wait_queue_entry_t* sleep_on ( wait_queue_head_t * wq )

Sets the state of the current process to TASK_UNINTERRUPTIBLE and inserts it into the specified wait queue.

Parameters

wq	Waitqueue where to sleep.

Returns: Pointer to the entry inside the wq representing the sleeping process.

◆ sys_exit()

void sys_exit ( int exit_code )

The exit() function causes normal process termination.

Parameters

exit_code The exit code.

◆ sys_getegid()

gid_t sys_getegid ( void )

returns the effective group ID of the calling process.

Returns: GID of the current process

◆ sys_geteuid()

uid_t sys_geteuid ( void )

Returns the effective User ID (UID) of the calling process.

Returns: The User ID.

◆ sys_getgid()

gid_t sys_getgid ( void )

returns the real group ID of the calling process.

Returns: GID of the current process

◆ sys_getpgid()

pid_t sys_getpgid ( pid_t pid )

returns the Process Group ID (PGID) of the process specified by pid. If pid is zero, the process ID of the calling process is used.

Parameters

pid	process of which we want to know the PGID.

Returns: the PGID of the specified process.

◆ sys_getpid()

pid_t sys_getpid ( void )

Returns the process ID (PID) of the calling process.

Returns: The process ID.

◆ sys_getppid()

pid_t sys_getppid ( void )

Returns the parent process ID (PPID) of the calling process.

Returns: The parent process ID.

◆ sys_getsid()

pid_t sys_getsid ( pid_t pid )

Return session id of the given process. If pid == 0 return the SID of the calling process If pid != 0 return the SID corresponding to the process having identifier == pid.

Parameters

pid	process identifier from wich we want the SID

Returns: On success return SID of the session Otherwise return -1 with errno set on: EPERM or ESRCH

◆ sys_getuid()

uid_t sys_getuid ( void )

Returns the real User ID (UID) of the calling process.

Returns: The User ID.

◆ sys_nice()

int sys_nice ( int increment )

Adds the increment to the priority value of the task.

Parameters

increment The modifier to apply to the nice value.

Returns: The new nice value.

◆ sys_sched_getparam()

int sys_sched_getparam	(	pid_t	pid,
		sched_param_t *	param
	)

Gets the scheduling settings for the given process.

Parameters

pid	ID of the process we are manipulating.
param	Where we store the parameters.

Returns: 1 on success, -1 on error.

◆ sys_sched_setparam()

int sys_sched_setparam	(	pid_t	pid,
		const sched_param_t *	param
	)

Set new scheduling settings for the given process.

Parameters

pid	ID of the process we are manipulating.
param	New parameters.

Returns: 1 on success, -1 on error.

◆ sys_setgid()

int sys_setgid ( gid_t gid )

sets the group ID of the calling process.

Parameters

gid group id

Returns: On success, zero is returned. Otherwise returns -1 with errno set to :EINVAL or EPERM.

◆ sys_setpgid()

int sys_setpgid	(	pid_t	pid,
		pid_t	pgid
	)

Sets the Process Group ID (PGID) of the process specified by pid. If pid is zero, the process ID of the calling process is used.

Parameters

pid	process of which we want to set the PGID.
pgid	the PGID we want to set.

Returns: returns zero. On error, -1 is returned, and errno is set appropriately.

◆ sys_setregid()

int sys_setregid	(	gid_t	rgid,
		gid_t	egid
	)

sets the real and effective group ID of the calling process.

Parameters

rgid	real group id
egid	effective group id

Returns: On success, zero is returned. Otherwise returns -1 with errno set to EPERM.

◆ sys_setreuid()

int sys_setreuid	(	uid_t	ruid,
		uid_t	euid
	)

Set the real and effective User ID (UID) of the calling process.

Parameters

ruid	the new real User ID.
euid	the new effective User ID.

Returns: On success, zero is returned. Otherwise returns -1 with errno set to EPERM.

◆ sys_setsid()

pid_t sys_setsid ( void )

creates a new session if the calling process is not a process group leader. The calling process is the leader of the new session (i.e., its session ID is made the same as its process ID). The calling process also becomes the process group leader of a new process group in the session (i.e., its process group ID is made the same as its process ID).

Returns: On success return SID of the session just created Otherwise return -1 with errno : EPERM

◆ sys_setuid()

int sys_setuid ( uid_t uid )

Tries to set the User ID (UID) of the calling process.

Parameters

uid	the new User ID.

Returns: On success, zero is returned. Otherwise returns -1 with errno set to :EINVAL or EPERM.

◆ sys_waitperiod()

int sys_waitperiod ( void )

Puts the process on wait until its next period starts.

Returns: 0 on success, a negative value on failure.

◆ sys_waitpid()

pid_t sys_waitpid	(	pid_t	pid,
		int *	status,
		int	options
	)

Suspends execution of the calling thread until a child specified by pid argument has changed state.

Parameters

pid	The pid to wait.
status	If not NULL, store status information here.
options	Determines the wait behaviour.

Returns: on success, returns the process ID of the terminated child; on error, -1 is returned.

◆ try_to_wake_up()

static int try_to_wake_up	(	task_struct *	process,
		unsigned	mode,
		int	sync
	)

inlinestatic

Awakens a sleeping process.

Parameters

process	The process that should be awakened
mode	The type of wait (TASK_INTERRUPTIBLE or TASK_UNINTERRUPTIBLE).
sync	Specifies if the wakeup should be synchronous.

Returns: 1 on success, 0 on failure.

Macros

Functions

Variables

Detailed Description

Macro Definition Documentation

◆ FAIL_ON_INV_ID_OR_PROC

◆ IF_PRIVILEGED_SET_ALL_AND_RETURN

◆ IF_RESET_SET_AND_RETURN

◆ RETURN_PROCESS_ATTR_OR_EPERM

◆ SET_IF_PRIVILEGED_OR_FAIL

Function Documentation

◆ __compute_utilization_factor()

◆ __response_time_analysis()

◆ default_wake_function()

◆ do_exit()

◆ enter_userspace()

◆ is_orphaned_pgrp()

◆ scheduler_dequeue_task()

◆ scheduler_enqueue_task()

◆ scheduler_enter_user_jmp()

◆ scheduler_get_active_processes()

◆ scheduler_get_current_process()

◆ scheduler_get_maximum_vruntime()

◆ scheduler_get_running_process()

◆ scheduler_getpid()

◆ scheduler_restore_context()

◆ scheduler_run()

◆ scheduler_store_context()

◆ sleep_on()

◆ sys_exit()

◆ sys_getegid()

◆ sys_geteuid()

◆ sys_getgid()

◆ sys_getpgid()

◆ sys_getpid()

◆ sys_getppid()

◆ sys_getsid()

◆ sys_getuid()

◆ sys_nice()

◆ sys_sched_getparam()

◆ sys_sched_setparam()

◆ sys_setgid()

◆ sys_setpgid()

◆ sys_setregid()

◆ sys_setreuid()

◆ sys_setsid()

◆ sys_setuid()

◆ sys_waitperiod()

◆ sys_waitpid()

◆ try_to_wake_up()