[PATCH] Added APA terms

[Richi Dubey]

---
 c-user/glossary.rst | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/c-user/glossary.rst b/c-user/glossary.rst
index 86350a8..589d41b 100644
--- a/c-user/glossary.rst
+++ b/c-user/glossary.rst
@@ -1,6 +1,6 @@
 .. SPDX-License-Identifier: CC-BY-SA-4.0
 
-.. Copyright (C) 2017, 2019 embedded brains GmbH (http://www.embedded-brains.de)
+.. Copyright (C) 2017, 2020 embedded brains GmbH (http://www.embedded-brains.de)
 .. Copyright (C) 1988, 1998 On-Line Applications Research Corporation (OAR)
 
 Glossary
@@ -16,6 +16,10 @@ Glossary
         A term used to describe an object which has been created by an
         application.
 
+    APA
+        Arbitrary Processor Affinity.
+        In this model, a thread is allowed to have an arbitrary affinity to the processor set, rather than a global mapping from one thread to all processors or one thread to one processor. It has two variants, :term:`Weak APA` and :term:`Strong APA`
+
     aperiodic task
         A task which must execute only at irregular intervals and has only a soft
         deadline.
@@ -777,6 +781,9 @@ Glossary
         :term:`return value` to indicate a successful operation or error
         conditions.
 
+    Strong APA
+        Strong APA is a specialization of :term:`APA`. In this model, on the arrival of a :term:`thread`, every thread reachable from the newly arrived thread is checked to see if an existing thread can be shifted (or deallocated its processor) and the newly arrived thread take its place if the newly arrived thread has a higher priority. Similar analysis is done when a thread finishes its execution (Here, the terms task and thread have interchangeable definitions). :cite:`Cerqueira:2014:LPA`
+
     suspend
         A term used to describe a task that is not competing for the CPU because it
         has had a ``rtems_task_suspend`` directive.
@@ -905,6 +912,10 @@ Glossary
         Message queues, regions, and semaphores have a wait queue associated with
         them.
 
+    Weak APA
+        Weak APA is a specialization of :term:`APA`. This refers to Linux's pull push implementation of APA model. On the arrival of a thread, the thread is scheduled when a processor in its affinity set is idle or a processor is executing a thread which is at a lower priority.
+        :cite:`Cerqueira:2014:LPA`
+
     YAML
         This term is an acronym for `YAML Ain't Markup Language <https://yaml.org/>`_.
 
-- 
2.17.1