Struct NodePool 

struct NodePool {
    head: AtomicU64,
}

A lock-free LIFO mailbox (stack) for kernel-internal IPC.

Messages are pushed atomically to the head of an intrusive linked list and popped from the head. This is not a FIFO queue : message order is reversed on reception.

Use case

Use for notification-style IPC between trusted kernel components where low latency (~10 cycles) matters more than message ordering. For FIFO-guaranteed IPC, use LockFreeRing. Lock-free LIFO pool of reusable MailboxMessage nodes.

Used by IntrusiveMailbox to avoid heap allocation in IRQ context. Nodes are recycled: after pop(), the node is returned to the pool instead of freed; on push(), the pool is checked first before allocating a fresh node.

ABA protection: the head pointer is tagged with a monotonic generation counter to prevent the ABA problem on concurrent pop/push cycles.

Fields

head: AtomicU64

Implementations

impl NodePool

const fn new() -> Self

fn preallocate(&self, count: usize)

Pre-allocate count nodes into the pool.

fn try_pop_raw(&self) -> Option<*mut MailboxMessage>

Try to pop a node from the pool (lock-free, ABA-safe).

fn push_raw(&self, ptr: *mut MailboxMessage)

Push a raw node pointer back into the pool (lock-free, ABA-safe).

Trait Implementations

impl Debug for NodePool

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.