MEMORYALLOCATORS(9) BSD Kernel Developer's Manual MEMORYALLOCATORS(9)NAMEmemoryallocators — introduction to kernel memory allocators
DESCRIPTION
The NetBSD kernel provides several memory allocators, each with different
characteristics and purpose. This document summarizes the main differ‐
ences between them.
The Kmem Allocator
The kmem allocator is modelled after an interface of similar name imple‐
mented in Solaris. This is main general purpose allocator in the kernel.
It is implemented on-top of the vmem(9) resource allocator (beyond the
scope of this document), meaning it will be using pool_cache(9) inter‐
nally to speed-up common (small) sized allocations.
It requires no setup, but cannot be used from interrupt context.
See kmem(9) for more details.
The Pool Allocator
The pool(9) allocator is a fixed-size memory allocator. It requires set‐
up (to initialize a memory pool) and is interrupt-safe.
See pool(9) for more details.
The Pool Cache Allocator
The pool cache allocator works on-top of the pool(9) allocator, also
allowing fixed-size allocation only, requires setup, and is interrupt-
safe.
The pool cache allocator is expected to be faster than other allocators,
including the “normal” pool allocator.
In the future this allocator is expected to have a per-CPU cache.
See pool_cache(9) for more details.
The UVM Kernel Memory Allocator
This is a low-level memory allocator interface. It allows variable-sized
allocations in multiples of PAGE_SIZE, and can be used to allocate both
wired and pageable kernel memory.
See uvm(9) for more details.
SEE ALSOintro(9), kmem(9), pool(9), pool_cache(9), uvm(9), vmem(9)AUTHORS
Elad Efrat ⟨elad@NetBSD.org⟩
YAMAMOTO Takashi ⟨yamt@NetBSD.org⟩
BSD August 3, 2009 BSD
