houseme 9bf102f965 fix(cache): reserve admitted bytes in the memory gate to bound burst overshoot (#4718) ...

The fill gate compared each request against a snapshot refreshed at most every
5 s, with no accounting for what it had already let through. A burst arriving
while the snapshot still read high therefore all passed the same check-then-act
test and over-allocated far past the real headroom before the next refresh — a
gap the burst stress test could expose but not close.

Track admitted bytes since the last refresh in the shared snapshot cell and
subtract them from available memory in `allows_fill`, reserving the request's
size on each admission. Cumulative admission is now bounded to the real budget
even though every fill reads the same stale snapshot; the refresh resets the
counter because the fresh reading already reflects those allocations. The
`min_free_memory_percent == 0` opt-out still short-circuits first, and the
already-low-memory path is unchanged.

New test `moka_backend_gate_reservation_bounds_burst_under_stale_snapshot`:
20 concurrent 40 KiB fills against a 500 KiB stale-high snapshot (300 KiB
budget) admit only a bounded handful, not the whole storm. Passed 10/10 runs;
mutation-verified — dropping the reservation admits all 20 and fails the test.

Refs: backlog#1107

Co-authored-by: heihutu <heihutu@gmail.com>

2026-07-11 05:36:20 +00:00

..

benches

test(object-data-cache): add concurrency stress tests and GET benchmarks (#4711)

2026-07-11 02:30:19 +00:00

src

fix(cache): reserve admitted bytes in the memory gate to bound burst overshoot (#4718)

2026-07-11 05:36:20 +00:00

Cargo.toml

test(object-data-cache): add concurrency stress tests and GET benchmarks (#4711)

2026-07-11 02:30:19 +00:00