Modernizing Linux swapping: introducing the swap table
3 days ago
- #Linux
- #Kernel Development
- #Memory Management
- The kernel's swap subsystem is critical for memory management and system performance.
- Kairui Song proposed simplifying and optimizing the swap code, with initial changes merged in Linux 6.18.
- Swap files handle anonymous memory when RAM is reclaimed, storing data in slower storage.
- Swap entries use a struct `swp_entry_t` to identify slots in swap files.
- Prior to 6.18, swap management involved complex structures like `swapper_spaces` and XArrays.
- The 6.18 update introduced a swap table (`swap_cluster_info`) to replace XArrays, improving scalability.
- The new swap table reduces memory usage and contention, leading to performance gains of 5-20%.
- Future updates aim to further simplify and enhance the swap subsystem.