Priority ordered list of threads. More...

#include <os-lists.h>

Inheritance diagram for os::rtos::internal::waiting_threads_list:

Public Types
Types and constants
using	iterator = utils::double_list_iterator< thread, waiting_thread_node, &waiting_thread_node::thread_ >
	Iterator over the list threads.

Public Member Functions
Constructors & Destructor
	waiting_threads_list ()
	Construct a list of waiting threads.

	~waiting_threads_list ()
	Destruct the list.

Public Member Functions
void	link (waiting_thread_node &node)
	Add a new thread node to the list.

volatile waiting_thread_node *	head (void) const
	Get list head.

bool	resume_one (void)
	Wake-up one thread (the oldest with the highest priority)

void	resume_all (void)
	Wake-up all threads in the list.

iterator	begin () const
	Iterator begin.

iterator	end () const
	Iterator begin.

Public Member Functions
bool	uninitialized (void) const
	Check if the list is uninitialised.

void	clear (void)
	Clear the list.

bool	empty (void) const
	Check if the list is empty.

volatile static_double_list_links *	tail (void) const
	Get the list tail.

Protected Member Functions
Private Member Functions
void	insert_after (static_double_list_links &node, static_double_list_links *after)
	Insert a new node after existing node.

Protected Attributes
Private Member Variables
static_double_list_links	head_
	A list node used to point to head and tail.

Detailed Description

Priority ordered list of threads.

There are at least two strategies:

keep the list ordered by priorities and have the top node easily accessible the head
preserve the insertion order and perform a full list traversal to determine the top node.

The first strategy requires a partial list traverse with each insert, to find the place to insert the node, but makes retrieving the top priority node trivial, by a single access to the list head.

The second strategy might minimise the overall processing time, but always requires a full list traversal to determine the top priority node.

On the other hand, typical waiting lists contain only one element, and in this case there is no distinction. Mutex objects occasionally might have two entries (and rarely more). Condition variables might also have several waiting threads, the number is usually small. In these cases, the distinction between the two strategies is also minimal.

In the rare cases when the waiting list is large, the first strategy favours top node retrieval, possibly improving the response time, and is thus preferred.

Definition at line 549 of file os-lists.h.

Member Typedef Documentation

◆ iterator

using os::rtos::internal::waiting_threads_list::iterator = utils::double_list_iterator<thread, waiting_thread_node, &waiting_thread_node::thread_>

Iterator over the list threads.

Definition at line 561 of file os-lists.h.

Constructor & Destructor Documentation

◆ waiting_threads_list()

os::rtos::internal::waiting_threads_list::waiting_threads_list ( )

inline

Construct a list of waiting threads.

The initial list status is empty.

Definition at line 934 of file os-lists.h.

◆ ~waiting_threads_list()

os::rtos::internal::waiting_threads_list::~waiting_threads_list ( )

inline

Destruct the list.

Definition at line 940 of file os-lists.h.

Member Function Documentation

◆ begin()

waiting_threads_list::iterator os::rtos::internal::waiting_threads_list::begin ( ) const

inline

Iterator begin.

Returns: An iterator positioned at the first element.

Definition at line 952 of file os-lists.h.

◆ clear()

void os::utils::static_double_list::clear ( void )

inherited

Clear the list.

Parameters: None.

Returns: Nothing.

Initialise the mandatory node with links to itself.

Definition at line 116 of file lists.cpp.

◆ empty()

bool os::utils::static_double_list::empty ( void ) const

inlineinherited

Check if the list is empty.

Parameters: None.

Return values

true	The list has no nodes.
false	The list has at least one node.

Definition at line 1049 of file lists.h.

◆ end()

waiting_threads_list::iterator os::rtos::internal::waiting_threads_list::end ( ) const

inline

Iterator begin.

Returns: An iterator positioned after the last element.

Definition at line 960 of file os-lists.h.

◆ head()

volatile waiting_thread_node * os::rtos::internal::waiting_threads_list::head ( void ) const

inline

Get list head.

Parameters: None.

Returns: Casted pointer to head node.

Definition at line 946 of file os-lists.h.

◆ insert_after()

void os::utils::static_double_list::insert_after	(	static_double_list_links &	node,
		static_double_list_links *	after
	)

protectedinherited

Insert a new node after existing node.

Parameters

node	Reference to node to insert.
after	Reference to existing node.

Returns: Nothing.

Definition at line 123 of file lists.cpp.

◆ link()

void os::rtos::internal::waiting_threads_list::link ( waiting_thread_node & node )

Add a new thread node to the list.

Parameters

[in] node Reference to a list node.

Returns: Nothing.

Based on priority, the node is inserted

at the end of the list,
at the beginning of the list,
in the middle of the list, which requires a partial list traversal (done from the end).

To satisfy the circular double linked list requirements, an empty list still contains the head node with references to itself.

Definition at line 190 of file os-lists.cpp.

◆ resume_all()

void os::rtos::internal::waiting_threads_list::resume_all ( void )

Wake-up all threads in the list.

Parameters: None.

Returns: Nothing.

Definition at line 284 of file os-lists.cpp.

◆ resume_one()

bool os::rtos::internal::waiting_threads_list::resume_one ( void )

Wake-up one thread (the oldest with the highest priority)

Parameters: None.

Return values

true	The list may have further entries.
false	The list is empty.

Atomically get the top thread from the list, remove the node and wake-up the thread.

Definition at line 247 of file os-lists.cpp.

◆ tail()

volatile static_double_list_links * os::utils::static_double_list::tail ( void ) const

inlineinherited

Get the list tail.

Parameters: None.

Returns: Pointer to tail node.

Definition at line 1062 of file lists.h.

◆ uninitialized()

bool os::utils::static_double_list::uninitialized ( void ) const

inlineinherited

Check if the list is uninitialised.

Parameters: None.

Return values

true	The list was not initialised.
false	The list was initialised.

Definition at line 1042 of file lists.h.

Member Data Documentation

◆ head_

static_double_list_links os::utils::static_double_list::head_

protectedinherited

A list node used to point to head and tail.

To simplify processing, the list always has a node.

Definition at line 498 of file lists.h.

The documentation for this class was generated from the following files:

Public Types

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Member Typedef Documentation

◆ iterator

Constructor & Destructor Documentation

◆ waiting_threads_list()

◆ ~waiting_threads_list()

Member Function Documentation

◆ begin()

◆ clear()

◆ empty()

◆ end()

◆ head()

◆ insert_after()

◆ link()

◆ resume_all()

◆ resume_one()

◆ tail()

◆ uninitialized()

Member Data Documentation

◆ head_