> [!NOTE] ![[assets/wl_lwlock_notifyqueuetail.png|256]] > > | | | > | :--- | :--- | > | **Wait Category** | LWLock | > | **Mechanism** | `NotifyQueueTailLock` | > | **Operations** | [[Operations/Other/FunctionScan]] | > | **Resources** | [[Resources/RAM|Memory]], [[Resources/CPU|CPU]] | > > Synchronization stall in the **IPC Cleanup Layer**. In the `LISTEN/NOTIFY` system, messages are stored in a circular buffer.