Windows® Internals, Sixth Edition, Part 2

Kernel-Mode Heaps (System Memory Pools)

At system initialization, the memory manager creates two dynamically sized memory pools, or heaps, that most kernel-mode components use to allocate system memory:

• Nonpaged pool Consists of ranges of system virtual addresses that are guaranteed to reside in physical memory at all times and thus can be accessed at any time without incurring a page fault; therefore, they can be accessed from any IRQL. One of the reasons nonpaged pool is required is because of the rule described in Chapter 2 in Part 1: page faults can’t be satisfied at DPC/dispatch level or above. Therefore, any code and data that might execute or be accessed at or above DPC/dispatch level must be in nonpageable memory.

• Paged pool A region of ...