Struct FramePool 

pub struct FramePool { /* private fields */ }

MTU-sized buffer pool for the virtio-net hot path.

Pins I-NET-4 (30-networking.md § 7): frame allocation goes through a pool of pre-allocated BytesMut buffers rather than vec![0u8; mtu] per-call. The pool is sized to MTU × 256 per direction (the 71 § 5 bench-harness gating value); bursts beyond the pool allocate fresh and are dropped on release rather than returned, so memory pressure spikes are bounded.

The pool is Send + Sync; per-backend instances share their RX/TX pools across the device thread and the host-side I/O thread without contention (a parking_lot::Mutex<Vec<BytesMut>> is the boot-time-cheap, hot-path- uncontended shape — RX or TX rarely interleave).

Implementations

impl FramePool

pub fn new(mtu: usize, pool_capacity: usize) -> Self

Build a pool with pool_capacity slots, each mtu bytes wide. Slots are allocated lazily on first acquire.

pub fn acquire(&self) -> BytesMut

Acquire a buffer of at least mtu capacity. The buffer is empty (len() == 0) on return; the caller fills it via BytesMut::extend_from_slice or unsafe { set_len(_) } after a read writes into the spare capacity.

pub fn release(&self, buf: BytesMut)

Return a buffer to the pool. Buffers beyond pool_capacity are dropped, bounding memory pressure under burst.

pub const fn capacity(&self) -> usize

Pool capacity (slots).

pub const fn mtu(&self) -> usize

Configured MTU (per-buffer minimum capacity).

pub fn free_count(&self) -> usize

Number of buffers currently in the free list (test/diagnostic).

Trait Implementations

impl Debug for FramePool

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

Formats the value using the given formatter.