Linux Kernel Journey

Sep 12, 2024 · Fundamentals

Understanding Linux Memory Allocation: Fast Path vs. Slow Path in the Source Code

This article dissects the Linux kernel's page allocation mechanisms, explaining how alloc_pages() follows a fast‑path using low watermarks and falls back to a slow‑path that triggers kswapd, direct reclaim, and compaction, while also detailing the corresponding page‑freeing functions and their internal data structures.