Linux mmap remains a foundational tool for engineers building high-performance systems, from databases to game engines. It allows file or device contents to be mapped directly into a process address space, avoiding explicit read/write syscalls and enabling zero-copy patterns. However, mmap is not a universal win: page fault costs, TLB pressure, and unpredictable latency under memory pressure can degrade performance. For large sequential reads, traditional read() with buffering often outperforms mmap. Modern alternatives like io_uring offer asynchronous I/O with lower overhead for certain workloads. This signal highlights the ongoing relevance of mmap in production systems and the need for careful benchmarking before adoption. Engineers should evaluate access patterns, file sizes, and concurrency models to decide between mmap, read/write, and io_uring.
A practical look at Linux mmap for high-performance I/O, shared memory, and file-backed mappings, with trade-offs and modern alternatives.