HP-UX 11i Internals

Kernel Memory Allocation

In Chapter 3, “The Kernel: Basic Organization,” we talked about how the kernel manages virtual and physical memory. Memory is divided into pages of 4 KB each. The kernel's page allocator handles allocating pages of memory to processes that need them. However, the kernel itself needs dynamic memory too, and it uses a different process. The memory allocations for the kernel are frequently for small areas of memory—the size of a proc structure or the size of a network buffer, for example. It would be impractical to just call the page allocator and request a page each time we need a small piece of memory. That's where the kernel memory allocator comes in. It handles requests for memory from the kernel, getting pages from ...