Struct PinnedBufferAllocator 

pub struct PinnedBufferAllocator { /* private fields */ }

A specialized buffer allocator that pins memory in coarse chunks (e.g. 1 MiB) for DMA.

The first chunk (chunk 0) is pinned at initialization and remains pinned for the lifetime of the allocator to eliminate pinning latency on requests. Additional chunks are pinned dynamically on demand when buffers spill over into them, and unpinned when all buffers within those chunks are dropped.

This allocator relies on BufferAllocator’s lowest-offset-first allocation strategy so that allocations pack into the permanently pinned first chunk before spilling over into dynamically pinned chunks.

Implementations

impl PinnedBufferAllocator

pub fn new( block_size: usize, source: BufferSource, bti: Bti, contiguity: u64, ) -> Self

Creates a new PinnedBufferAllocator with default chunk size (1 MiB).

contiguity specifies the minimum physical address contiguity (in bytes) required by the hardware/BTI, which determines the granularity of entries in paddrs.

pub fn with_chunk_size( block_size: usize, source: BufferSource, bti: Bti, contiguity: u64, chunk_size: usize, ) -> Self

Creates a new PinnedBufferAllocator with a custom chunk_size.

contiguity specifies the minimum physical address contiguity (in bytes) required by the hardware/BTI, which determines the granularity of entries in paddrs.

pub fn block_size(&self) -> usize

pub fn chunk_size(&self) -> usize

pub fn contiguity(&self) -> u64

pub fn buffer_source(&self) -> &BufferSource

pub fn vmo(&self) -> Option<Arc<Vmo>>

Returns the underlying VMO for DMA operations.

pub fn is_trusted(&self) -> bool

pub fn clean_transfer_buffer(&self)

Decommits unallocated pages in the buffer so the kernel can reclaim memory.

pub fn paddrs(&self, range: &Range<usize>) -> Option<(&[zx_paddr_t], u64)>

Returns a slice of physical addresses covering range and the contiguity granularity (in bytes) represented by each address in the slice.

pub fn try_allocate_buffer( &self, size: usize, ) -> Result<PinnedBuffer<'_>, EventListener>

pub fn allocate_buffer_sync(&self, size: usize) -> PinnedBuffer<'_>

pub fn allocate_buffer(&self, size: usize) -> PinnedBufferFuture<'_>

pub fn try_allocate_buffer_owned( self: &Arc<Self>, size: usize, ) -> Result<OwnedBuffer, EventListener>

pub fn allocate_buffer_sync_owned(self: &Arc<Self>, size: usize) -> OwnedBuffer

Trait Implementations

impl BufferAllocator for PinnedBufferAllocator

fn free_buffer(&self, range: Range<usize>)

Frees or reclaims the specified memory range.

fn identifier(&self) -> usize

Returns an identifier for this allocator based on its memory address.

fn is_trusted(&self) -> bool

Returns true if buffers produced by this allocator are trusted (unshared).

fn vmo(&self) -> Option<Arc<Vmo>>

Returns the underlying VMO if backed by a VMO and untrusted.

fn paddrs(&self, range: &Range<usize>) -> Option<(&[zx_paddr_t], u64)>

Returns the physical addresses for range if pinned, along with the contiguity.

impl Debug for PinnedBufferAllocator

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

Formats the value using the given formatter.

impl Drop for PinnedBufferAllocator

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.

impl Send for PinnedBufferAllocator

impl Sync for PinnedBufferAllocator

impl<'a> TryAllocateBuffer<'a> for PinnedBufferAllocator

type Buffer = BufferImpl<'a, &'a PinnedBufferAllocator, PinnedBufferAllocator>

fn try_allocate_buffer( &'a self, size: usize, ) -> Result<PinnedBuffer<'a>, EventListener>

Attempts to allocate a buffer of size bytes. Returns an EventListener to wait on if memory is temporarily unavailable.

fn allocate_buffer_sync(&'a self, size: usize) -> Self::Buffer

Allocates a buffer synchronously, blocking the current thread until memory is available.