Expand description
Kernel Same-page Merging (KSM)
Scans anonymous user-space pages for identical content and merges duplicates via Copy-on-Write (COW) mappings. Reduces memory consumption for workloads with many similar processes (e.g. KDE Plasma applets, browser tabs, containerized services).
Design:
- Unstable tree: pages seen once, awaiting confirmation across multiple scan cycles before promotion.
- Stable tree: pages confirmed identical, merged via COW.
- FNV-1a hash: fast 32-bit content hash for candidate filtering (integer-only, no floating point).
- Full comparison: byte-for-byte equality check on hash match before merging.
Pages are identified by frame number (FrameNumber). The scanner
does not touch kernel pages, device-mapped pages, or already-merged
pages.
Structs§
- KsmScanner
- Kernel Same-page Merging scanner.
- KsmStats
- Statistics reported by the KSM scanner.