From f4377b4479efdefc37f0e84c88568318eb89a9d2 Mon Sep 17 00:00:00 2001 From: Sebastian Huber Date: Tue, 26 Jul 2022 11:40:21 +0200 Subject: c-user: Document new rtems_task_delete() behaviour Update #4679. --- c-user/task/directives.rst | 25 ++++++++++++++++++++----- 1 file changed, 20 insertions(+), 5 deletions(-) (limited to 'c-user') diff --git a/c-user/task/directives.rst b/c-user/task/directives.rst index 64b591d..b78aaa9 100644 --- a/c-user/task/directives.rst +++ b/c-user/task/directives.rst @@ -805,14 +805,26 @@ specified by ``id``. :c:macro:`RTEMS_CALLED_FROM_ISR` The directive was called from within interrupt context. +:c:macro:`RTEMS_INCORRECT_STATE` + The task termination procedure was started, however, waiting for the + terminating task would have resulted in a deadlock. + :c:macro:`RTEMS_ILLEGAL_ON_REMOTE_OBJECT` The task resided on a remote node. .. rubric:: NOTES: -RTEMS stops the execution of the task and reclaims the stack memory, any -allocated delay or timeout timers, the TCB, and, if the task is -:c:macro:`RTEMS_FLOATING_POINT`, its floating point context area. RTEMS +The task deletion is done in several steps. Firstly, the task is marked as +terminating. While the task life of the terminating task is protected, it +executes normally until it disables the task life protection or it deletes +itself. A terminating task will eventually stop its normal execution and start +its termination procedure. The procedure executes in the context of the +terminating task. The task termination procedure involves the destruction of +POSIX key values and running the task termination user extensions. Once +complete the execution of the task is stopped and task-specific resources are +reclaimed by the system, such as the stack memory, any allocated delay or +timeout timers, the :term:`TCB`, and, if the task is +:c:macro:`RTEMS_FLOATING_POINT`, its floating point context area. RTEMS explicitly does not reclaim the following resources: region segments, partition buffers, semaphores, timers, or rate monotonic periods. @@ -824,10 +836,13 @@ resources before deletion. A task can be directed to release its resources and delete itself by restarting it with a special argument or by sending it a message, an event, or a signal. -Deletion of the current task (:c:macro:`RTEMS_SELF`) will force RTEMS to select +Deletion of the calling task (:c:macro:`RTEMS_SELF`) will force RTEMS to select another task to execute. -The :term:`TCB` for the deleted task is reclaimed by RTEMS. +When a task deletes another task, the calling task waits until the task +termination procedure of the task being deleted has completed. The terminating +task inherits the :term:`eligible priorities ` of the +calling task. When a global task is deleted, the task identifier must be transmitted to every node in the system for deletion from the local copy of the global object table. -- cgit v1.2.3