//! metop: Linux memory analysis TUI.
//!
//! Two-tier sampling, driven by measured costs:
//! tier 1 (every tick): /proc/<pid>/statm, ~15-30 ms for the whole system
//! tier 2 (budgeted): /proc/<pid>/smaps_rollup, 1.5 ms avg, up to 19 ms
//! detail (on demand): /proc/<pid>/smaps, 30-40 ms