Chapter 12 Kernel Memory Allocation Introduction Resource Map

Chapter 12 Kernel Memory Allocation Introduction Resource Map Introduction • page level allocator – paging system • supports virtual memory system – kernel memory allocator • provides odd sized buffers of memory to various kernel subsystems • kernel frequently needs chunks of memory of various sizes usually for short periods of time 2. Explore kernel memory allocation methods: resource maps, buddy systems, slab allocators, and more. learn efficient memory management in operating systems.

Chapter 12 Kernel Memory Allocation Introduction Resource Map Introduction • page level allocator • paging system • supports virtual memory system • kernel memory allocator • provides odd sized buffers of memory to various kernel subsystems • kernel frequently needs chunks of memory of various sizes usually for short periods of time. Kernel memory allocator (kma)• functional requirements– page level allocator pre allocates part of main memory to kma, which must use this memory pool efficiently. Since the kernel runs critical tasks and needs memory frequently, allocation must be fast, efficient, and minimize fragmentation. common strategies include the buddy system (general purpose block allocation) and the slab system (object based allocation). Two kinds of memory allocation in the kernel: add pages to the virtual address space of the kernel, or to the virtual address space of a specific user process allocate a chunk of memory for use by the kernel (e.g. for a process control block, for use by a system call, etc.).

Chapter 12 Kernel Memory Allocation Introduction Resource Map Since the kernel runs critical tasks and needs memory frequently, allocation must be fast, efficient, and minimize fragmentation. common strategies include the buddy system (general purpose block allocation) and the slab system (object based allocation). Two kinds of memory allocation in the kernel: add pages to the virtual address space of the kernel, or to the virtual address space of a specific user process allocate a chunk of memory for use by the kernel (e.g. for a process control block, for use by a system call, etc.). An allocation scheme that combines free buffer coalescing with a power of two allocator memory is split into blocks of pages where each block is a power of two number of pages. Introduction page level allocator paging system supports virtual memory system kernel memory allocator provides odd sized buffers of memory to various kernel subsystems kernel frequently needs chunks of memory of various sizes usually for short periods of time introduction (cont) users of the kernel memory allocator pathname translation routine. Allocating kernel memory treated differently from user memory often allocated from a free memory pool kernel requests memory for structures of varying sizes some kernel memory needs to be contiguous i.e. for device i o. The document discusses unix memory management and various kernel memory allocation techniques. it describes how unix uses demand paged virtual memory with pages as the basic unit of memory management.

Chapter 12 Kernel Memory Allocation Introduction Resource Map An allocation scheme that combines free buffer coalescing with a power of two allocator memory is split into blocks of pages where each block is a power of two number of pages. Introduction page level allocator paging system supports virtual memory system kernel memory allocator provides odd sized buffers of memory to various kernel subsystems kernel frequently needs chunks of memory of various sizes usually for short periods of time introduction (cont) users of the kernel memory allocator pathname translation routine. Allocating kernel memory treated differently from user memory often allocated from a free memory pool kernel requests memory for structures of varying sizes some kernel memory needs to be contiguous i.e. for device i o. The document discusses unix memory management and various kernel memory allocation techniques. it describes how unix uses demand paged virtual memory with pages as the basic unit of memory management.