The kernel and device drivers use nonpaged pool to store data that might be accessed when the system can’t handle page faults. The heap manager satisfies subsequent allocations using memory from the free region, which begins just past the 512-byte region that is allocated. Because the minimum virtual memory allocation size is a multiple of the system page size (4KB on x86 and 圆4), these subsidiary memory managers carve up larger allocations into smaller ones so that memory isn’t wasted.įor example, if an application wants a 512-byte buffer to store some data, a heap manager takes one of the regions it has allocated and notes that the first 512-bytes are in use, returning a pointer to that memory and putting the remaining memory on a list it uses to track free heap regions. The kernel’s pool manager operates similarly to the C-runtime and Windows heap managers that execute within user-mode processes. The pool manager operates in kernel mode, using regions of the system’s virtual address space (described in the Pushing the Limits post on virtual memory) for the memory it sub-allocates. Paged and nonpaged pools serve as the memory resources that the operating system and device drivers use to store their data structures. Pushing the Limits of Windows: USER and GDI Objects – Part 2

Pushing the Limits of Windows: USER and GDI Objects – Part 1 Pushing the Limits of Windows: Processes and Threads Pushing the Limits of Windows: Paged and Nonpaged Pool Pushing the Limits of Windows: Virtual Memory Pushing the Limits of Windows: Physical Memory While they can stand on their own, they assume that you read them in order. Here’s the index of the entire Pushing the Limits series.

This time I’m going to describe two fundamental kernel resources, paged pool and nonpaged pool, that are based on those, and that are directly responsible for many other system resource limits including the maximum number of processes, synchronization objects, and handles. In previous Pushing the Limits posts, I described the two most basic system resources, First published on TechNet on Mar 10, 2009

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