Linux

A deep dive into Linux Page Cache — how VFS, inode, and address_space organize cached file content, how Buffered I/O and mmap create and release cache pages, the four mmap mapping types, and the tools to observe cache hit rates.

Zero-copy techniques in Linux — starting from the traditional read/write path (4 context switches, 2 DMA + 2 CPU copies) and walking through Direct I/O, mmap, sendfile, DMA gather, splice, and COW.

How Linux organizes physical memory — comparing FLATMEM, DISCONTIGMEM, and SPARSEMEM, and how each model implements pfn_to_page / page_to_pfn.