Module concurrent_gate 

Concurrent restart throttle gates for preventing restart storm.

This module implements instance-global and group-level concurrent restart limits to prevent resource contention during mass failure scenarios.

Permit-based design

GatePermit is an RAII guard returned by SupervisorInstanceGate::try_acquire. The gate slot is released automatically when the GatePermit is dropped, eliminating the “mismatched acquire/release” bug class where a single acquire was followed by multiple releases (e.g. OneForAll restart scope).

Structs

CombinedThrottleGate

Combined throttle gate that enforces both instance and group limits.

GatePermit

RAII guard that represents one acquired concurrent restart slot.

GroupLevelGate

Group-level concurrent restart gate for optional per-group throttling.

SupervisorInstanceGate

Instance-global concurrent restart gate counter.