Module layout 

2026-09-25: On-disk layout of the high-speed-swap KV tier: one pre-allocated file per layer, layer_{:05}.kv under HighSpeedSwapConfig::dir (--high-speed-swap-dir).

Owner: storage, high-speed swap. Invariants:

• A Layout holds one open file per layer of spec, each at least spec.bytes_per_layer() long; create and open return an error otherwise.

On Linux the files are opened O_DIRECT. Space is reserved with posix_fallocate on unix and set_len on Windows.

Structs

Layout