Struct TierManager 

pub struct TierManager<const MAX_REGIONS: usize> { /* private fields */ }

Manages tier placement for a fixed set of memory regions.

MAX_REGIONS is the compile-time upper bound on tracked regions. This avoids heap allocation and is suitable for no_std environments.

Implementations

impl<const MAX_REGIONS: usize> TierManager<MAX_REGIONS>

pub const fn new() -> Self

Create a new TierManager with default DC-1 thresholds.

pub const fn with_thresholds(thresholds: TierThresholds) -> Self

Create a new TierManager with custom thresholds.

pub const fn count(&self) -> usize

Return the number of tracked regions.

pub const fn current_epoch(&self) -> u32

Return the current epoch.

pub fn advance_epoch(&mut self)

Advance the epoch counter. Call this once per scheduler epoch.

pub fn register( &mut self, region_id: OwnedRegionId, initial_tier: Tier, ) -> RvmResult<()>

Register a new region in the tier manager at the given initial tier.

Errors

Returns RvmError::ResourceLimitExceeded if the manager is at capacity. Returns RvmError::MemoryOverlap if the region is already registered.

pub fn unregister(&mut self, region_id: OwnedRegionId) -> RvmResult<()>

Unregister a region from the tier manager.

Errors

Returns RvmError::PartitionNotFound if the region is not tracked.

pub fn record_access(&mut self, region_id: OwnedRegionId) -> RvmResult<()>

Record an access to the given region, updating its recency score.

Errors

Returns RvmError::PartitionNotFound if the region is not tracked.

pub fn update_cut_value( &mut self, region_id: OwnedRegionId, cut_value: u16, ) -> RvmResult<()>

Update the cut value for a region (from the coherence engine).

Errors

Returns RvmError::PartitionNotFound if the region is not tracked.

pub fn promote( &mut self, region_id: OwnedRegionId, target_tier: Tier, ) -> RvmResult<Tier>

Promote a region to a higher (lower-numbered) tier.

Returns the previous tier on success.

Errors

Returns RvmError::PartitionNotFound if the region is not tracked. Returns RvmError::InvalidTierTransition if the target tier is not higher than the current tier, or if promoting from Cold. Returns RvmError::CoherenceBelowThreshold if the residency score does not meet the promotion threshold.

pub fn demote( &mut self, region_id: OwnedRegionId, target_tier: Tier, ) -> RvmResult<Tier>

Demote a region to a lower (higher-numbered) tier.

Returns the previous tier on success.

Errors

Returns RvmError::PartitionNotFound if the region is not tracked. Returns RvmError::InvalidTierTransition if the target tier is not lower than the current tier.

pub fn get(&self, region_id: OwnedRegionId) -> Option<&RegionTierState>

Return the current tier state for a region, if tracked.

pub fn decay_recency(&mut self, decay_amount: u16)

Decay recency scores for all tracked regions by the given amount (in basis points). Call this once per epoch to age out stale regions.

pub fn find_demotion_candidates( &self, out: &mut [(OwnedRegionId, Tier)], ) -> usize

Identify regions that should be demoted based on current thresholds.

Returns (region_id, recommended_target_tier) pairs. Caller is responsible for acting on recommendations (e.g., triggering compression for Dormant demotion).

out is a caller-provided buffer; returns the number of entries written.

Trait Implementations

impl<const MAX_REGIONS: usize> Default for TierManager<MAX_REGIONS>

fn default() -> Self

Returns the “default value” for a type.