Chapter 3. Understanding user process models

This chapter explains several memory models available on AIX and how these models affect the heap and shared memory usage in your applications by providing the following sections:

• Section 3.1, “User process models on AIX” on page 106

• Section 3.2, “The 32-bit user process model” on page 109

• Section 3.3, “The 64-bit user process model” on page 130

• Section 3.4, “Introduction to shared memory” on page 140

• Section 3.5, “Shared memory segments allocation order” on page 149

• Section 3.6, “Large page support” on page 157

For further information about the topics explained in this chapter, please refer to the following sections in AIX 5L Version 5.2 General Programming Concepts: Writing and Debugging Programs:

• “Shared Libraries and Shared Memory”

• “System Memory Allocation Using the malloc Subsystem”