Adaptive Partitioning - Memory #

Aka APM

What is it?#

It's a flexible, per memory class partitioning mechanism that allows for the independent specification of both memory resource guarantees (reservations) and restrictions for each process in a running system.

Memory Partitioning is part of an overall resource partitioning strategy. See Adaptive Partitioning.

Table of Contents#

1. QNX Designer's Documentation
   • Overview
   • What do you mean by a memory class?

1. Hacking
   • Where to find the source code - coming soon
   • How to build APM - coming soon
2. Links to user documention:
   • Memory Partitioning - Design and Architecture Overview
   • Adaptive Partitioning User's Guide
   • Installation Notes - coming soon
   • Release Notes - coming soon
   • AP Command Reference - coming soon
   • Library reference for posix_spawn() - coming soon
   • APM chapter from the QNX System Architecture guide - coming soon

Overview#

What do you mean by a memory class?#

In the context of memory partitioning, a memory class refers specifically to an independently partition-able segment of non-overlapping memory. The segments are established at startup and refer to the syspage asinfo entries (visible with pidin syspage=asinfo). The system architect is free to ascribe any attributes or purpose to the memory segments as memory partitioning does not impose any such attributes. Once defined in startup, as subsequently added to the partitioning name space, each of these segments is referred to as a class (or type if you prefer) for the purpose of partitioning and allocation/deallocation.

How do I allocate memory of a different class?#

We (currently) rely on the POSIX typed memory interfaces for this.

How can I use this?#