Struct AdmissionFilter 

pub struct AdmissionFilter {
    pub ghost_mask: usize,
    pub ghost_set: Arc<[AtomicU16]>,
}

Ghost Set — direct-mapped fingerprint array.

Records the 16-bit fingerprint of evicted items so that previously-hot items bypass TLS probation on re-insertion.

Task 5 — Capacity Align

Ghost Set size is always equal to the Arena’s capacity (already a power of two). When the user sets a small capacity (e.g. 2000 items rounded to 2048), the Ghost Set is also 2048 × 2 bytes = 4 KB — not the previous bloated capacity.next_power_of_two() of a larger default.

Fields

ghost_mask: usize

ghost_set: Arc<[AtomicU16]>

Implementations

impl AdmissionFilter

pub fn new(capacity: usize) -> Self

capacity must be a power of two (enforced by Config). Ghost Set is exactly capacity entries (2 bytes each).

pub fn record_death(&self, hash: u64)

Called by Daemon on eviction: record this item’s 16-bit fingerprint.

pub fn check_ghost(&self, hash: u64) -> bool

Called by Worker on insert: true if the fingerprint matches a previously evicted item → bypass TLS probation.

pub fn clear(&self)