os::rtos::internal::ready_threads_list Class Reference

Priority ordered list of threads waiting too run. More...

#include <os-lists.h>

Inheritance diagram for os::rtos::internal::ready_threads_list:

Public Member Functions
Constructors & Destructor
	ready_threads_list ()
	Construct a list of waiting threads.
	~ready_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.
thread *	unlink_head (void)
	Remove the top node from the list.
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

Definition at line 458 of file os-lists.h.

Constructor & Destructor Documentation

ready_threads_list()

os::rtos::internal::ready_threads_list::ready_threads_list ( )

inline

The initial list status is empty.

Definition at line 895 of file os-lists.h.

      {
      }

~ready_threads_list()

os::rtos::internal::ready_threads_list::~ready_threads_list ( )

inline

Definition at line 899 of file os-lists.h.

      {
      }

Member Function Documentation

clear()

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

inherited

Parameters

None.

Returns

Nothing.

Initialise the mandatory node with links to itself.

Definition at line 108 of file lists.cpp.

    {
#pragma GCC diagnostic push
#if defined(__clang__)
#elif defined(__GNUC__)
#pragma GCC diagnostic ignored "-Wuseless-cast"
#endif
      head_.next (const_cast<static_double_list_links*> (&head_));
      head_.prev (const_cast<static_double_list_links*> (&head_));
#pragma GCC diagnostic pop
    }

References os::utils::static_double_list::head_, os::utils::static_double_list_links::next(), and os::utils::static_double_list_links::prev().

Referenced by os::utils::double_list::double_list(), link(), and os::rtos::internal::terminated_threads_list::link().

empty()

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

inlineinherited

Parameters

None.

Return values

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

Definition at line 1001 of file lists.h.

    {
      // If it points to itself, it is empty.
      return (head_.next () == &head_) || (head_.next () == nullptr);
    }

References os::utils::static_double_list::head_, and os::utils::static_double_list_links::next().

Referenced by os::utils::double_list::~double_list(), os::rtos::internal::clock_timestamps_list::check_timestamp(), os::rtos::internal::clock_timestamps_list::link(), link(), os::rtos::internal::waiting_threads_list::link(), os::rtos::internal::waiting_threads_list::resume_one(), and unlink_head().

head()

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

inline

Parameters

None.

Returns

Casted pointer to head node.

Definition at line 904 of file os-lists.h.

      {
        return static_cast<volatile waiting_thread_node*> (
            static_double_list::head ());
      }

Referenced by link(), and unlink_head().

insert_after()

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

protectedinherited

Parameters

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

Returns

Nothing.

Definition at line 121 of file lists.cpp.

    {
#if defined(OS_TRACE_UTILS_LISTS)
      trace::printf ("%s() n=%p after %p\n", __func__, &node, after);
#endif
 
      // Unlinked nodes must have both pointers null.
      // If not, most probably the node was already linked.
      // Or the memory is corrupted.
      assert (node.prev () == nullptr);
      assert (node.next () == nullptr);
 
      // The `after` node must be linked. Only the `next` pointer is
      // tested, since only it is used.
      assert (after->next () != nullptr);
 
      // Make the new node point to its neighbours.
      node.prev (after);
      node.next (after->next ());
 
      // Make the neighbours point to the node. The order is important.
      after->next ()->prev (&node);
      after->next (&node);
    }

References os::utils::static_double_list_links::next(), os::utils::static_double_list_links::prev(), and os::trace::printf().

Referenced by os::rtos::internal::thread_children_list::link(), os::rtos::internal::clock_timestamps_list::link(), link(), os::rtos::internal::waiting_threads_list::link(), and os::rtos::internal::terminated_threads_list::link().

link()

void os::rtos::internal::ready_threads_list::link

(

waiting_thread_node &

node

)

Parameters

[in]

node

Reference to a list node.

Returns

Nothing.

Definition at line 47 of file os-lists.cpp.

      {
        if (head_.prev () == nullptr)
          {
            // If this is the first time, initialise the list to empty.
            clear ();
          }
 
        thread::priority_t prio = node.thread_->priority ();
 
        waiting_thread_node* after = static_cast<waiting_thread_node*> (
            const_cast<utils::static_double_list_links*> (tail ()));
 
        if (empty ())
          {
            // Insert at the end of the list.
#if defined(OS_TRACE_RTOS_LISTS)
            trace::printf ("ready %s() empty +%u\n", __func__, prio);
#endif
          }
        else if (prio <= after->thread_->priority ())
          {
            // Insert at the end of the list.
#if defined(OS_TRACE_RTOS_LISTS)
            trace::printf ("ready %s() back %u +%u \n", __func__,
                           after->thread_->priority (), prio);
#endif
          }
        else if (prio > head ()->thread_->priority ())
          {
#pragma GCC diagnostic push
#if defined(__clang__)
#elif defined(__GNUC__)
#pragma GCC diagnostic ignored "-Wuseless-cast"
#endif
            // Insert at the beginning of the list.
            after = static_cast<waiting_thread_node*> (
                const_cast<utils::static_double_list_links*> (&head_));
#pragma GCC diagnostic pop
 
#if defined(OS_TRACE_RTOS_LISTS)
            trace::printf ("ready %s() front +%u %u \n", __func__, prio,
                           head ()->thread_->priority ());
#endif
          }
        else
          {
#pragma GCC diagnostic push
#if defined(__clang__)
#elif defined(__GNUC__)
#pragma GCC diagnostic ignored "-Wuseless-cast"
#endif
            // Insert in the middle of the list.
            // The loop is guaranteed to terminate, and not hit the head.
            // The weight is relatively small, priority() is not heavy.
            while (prio > after->thread_->priority ())
              {
                after = static_cast<waiting_thread_node*> (
                    const_cast<utils::static_double_list_links*> (
                        after->prev ()));
              }
#pragma GCC diagnostic pop
 
#if defined(OS_TRACE_RTOS_LISTS)
            trace::printf ("ready %s() middle %u +%u \n", __func__,
                           after->thread_->priority (), prio);
#endif
          }
 
        insert_after (node, after);
 
        node.thread_->state_ = thread::state::ready;
      }

References os::utils::static_double_list::clear(), os::utils::static_double_list::empty(), head(), os::utils::static_double_list::head_, os::utils::static_double_list::insert_after(), os::utils::static_double_list_links::prev(), os::trace::printf(), os::rtos::thread::priority(), os::rtos::thread::state::ready, os::utils::static_double_list::tail(), and os::rtos::internal::waiting_thread_node::thread_.

tail()

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

inlineinherited

Parameters

None.

Returns

Pointer to tail node.

Definition at line 1014 of file lists.h.

    {
      return (head_.prev ());
    }

References os::utils::static_double_list::head_, and os::utils::static_double_list_links::prev().

Referenced by os::rtos::internal::thread_children_list::link(), os::rtos::internal::clock_timestamps_list::link(), link(), os::rtos::internal::waiting_threads_list::link(), and os::rtos::internal::terminated_threads_list::link().

uninitialized()

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

inlineinherited

Parameters

None.

Return values

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

Definition at line 994 of file lists.h.

    {
      // If it points to nowhere, it is not yet initialised.
      return (head_.prev () == nullptr);
    }

References os::utils::static_double_list::head_, and os::utils::static_double_list_links::prev().

unlink_head()

thread * os::rtos::internal::ready_threads_list::unlink_head

(

void

)

Parameters

None.

Returns

Pointer to thread.

Must be called in a critical section.

Definition at line 126 of file os-lists.cpp.

      {
        assert (!empty ());
 
        thread* th = head ()->thread_;
 
#if defined(OS_TRACE_RTOS_LISTS)
        trace::printf ("ready %s() %p %s\n", __func__, th, th->name ());
#endif
 
        const_cast<waiting_thread_node*> (head ())->unlink ();
 
        assert (th != nullptr);
 
        // Unlinking is immediately followed by a context switch,
        // so in order to guarantee that the thread is marked as
        // running, it is saver to do it here.
 
        th->state_ = thread::state::running;
        return th;
      }

References os::utils::static_double_list::empty(), head(), os::rtos::internal::object_named::name(), os::trace::printf(), os::rtos::thread::state::running, os::rtos::internal::waiting_thread_node::thread_, and unlink().

Member Data Documentation

head_

static_double_list_links os::utils::static_double_list::head_

protectedinherited

To simplify processing, the list always has a node.

Definition at line 473 of file lists.h.

Referenced by os::rtos::internal::waiting_threads_list::begin(), os::rtos::internal::clock_timestamps_list::check_timestamp(), os::utils::static_double_list::clear(), os::utils::static_double_list::empty(), os::rtos::internal::waiting_threads_list::end(), os::utils::static_double_list::head(), os::rtos::internal::clock_timestamps_list::link(), link(), os::rtos::internal::waiting_threads_list::link(), os::rtos::internal::terminated_threads_list::link(), os::utils::static_double_list::tail(), and os::utils::static_double_list::uninitialized().

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

• os-lists.h
• os-lists.cpp