CMA

OPPO Kernel Craftsman

Mar 10, 2023 · Fundamentals

CMA (Contiguous Memory Allocator) Technical Principle Analysis and Source Code Interpretation

Linux’s Contiguous Memory Allocator (CMA) reserves and manages large physical memory blocks for devices by integrating with the Buddy system, using structures like struct cma, bitmap allocation, and APIs such as cma_init_reserved_mem and cma_alloc, while handling page migration, LRU and per‑CPU PCP caches to ensure efficient allocation and release.