Struct LayerPager 

pub struct LayerPager { /* private fields */ }

LRU weight pager — evicts cold tensors to free RAM, loads from source on demand.

Pinned tensors

Tensors whose TensorId is in the pinned set are never evicted. If pinned tensors alone exceed the budget, eviction will exhaust all non-pinned candidates and then stop (no error); the budget acts as a best-effort target.

Acquiring tensors

Call acquire to get an Arc<ResidentTensor> for a tensor by ID. The result shares ownership with the pager’s resident map, so the bytes stay alive as long as either the pager or the caller holds a reference — eviction only removes the pager’s entry, not the data itself.

Implementations

impl LayerPager

pub fn new( source: Arc<dyn PagerSource>, tensor_map: HashMap<TensorId, TensorEntry>, budget_bytes: u64, pinned: HashSet<TensorId>, ) -> Self

Create a new pager.

Parameters

• source — backing weight store (file or mmap).
• tensor_map — map from TensorId to file offset + size.
• budget_bytes — maximum resident bytes (use u64::MAX for unlimited).
• pinned — set of tensor IDs that are never evicted.

pub fn acquire( &self, id: &TensorId, ) -> Result<Arc<ResidentTensor>, RuntimeError>

Acquire a tensor, loading it from the source if not currently resident.

The LRU order is updated on every successful acquire. If the tensor must be loaded, the pager first evicts non-pinned tensors until the budget allows the new allocation, then reads the bytes from source.

Errors

• RuntimeError::TensorNotFound — id is not in the tensor map.
• RuntimeError::LockPoisoned — an internal lock was poisoned.
• RuntimeError::OffloadEof / RuntimeError::Io — source read failed.

pub fn resident_bytes(&self) -> u64

Return the number of bytes currently resident in RAM.

pub fn resident_count(&self) -> usize

Return the number of tensors currently resident in RAM.

pub fn budget_bytes(&self) -> u64

Return the configured RAM budget in bytes.

pub fn is_resident(&self, id: &TensorId) -> bool

Check whether a tensor is currently resident.

pub fn is_pinned(&self, id: &TensorId) -> bool

Check whether a tensor is pinned (will never be evicted).