Struct StorageIOScheduler 

pub struct StorageIOScheduler { /* private fields */ }

I/O request scheduler with deadline-aware, priority-based ordering.

Ordering rules

1. Requests whose deadline_tick is at or before the current tick are dispatched first (earliest deadline first).
2. Among non-deadline-urgent requests, higher IOPriority wins.
3. Ties within the same priority level are broken by enqueue order (FIFO).

Implementations

impl StorageIOScheduler

pub fn new(config: SchedulerConfig) -> Self

Create a new scheduler with the given configuration.

pub fn submit( &mut self, block_cid: &str, direction: IODirection, priority: IOPriority, size_bytes: u64, deadline_tick: Option<u64>, ) -> Result<u64, String>

Submit a new I/O request.

Returns the unique request ID on success, or an error if the pending queue is at capacity.

pub fn next_request(&mut self) -> Option<IORequest>

Pop and return the highest-priority pending request.

Ordering:

• Deadline-urgent requests (deadline ≤ current tick) come first, ordered by earliest deadline, then FIFO.
• Non-urgent requests follow, ordered by priority desc then FIFO.

pub fn complete( &mut self, request_id: u64, direction: IODirection, size_bytes: u64, )

Record the completion of a previously dispatched request.

Updates internal counters for reads, writes, and bytes scheduled.

pub fn cancel(&mut self, request_id: u64) -> bool

Cancel a pending request by ID.

Returns true if the request was found and removed.

pub fn pending_count(&self) -> usize

Number of requests currently pending dispatch.

pub fn pending_reads(&self) -> usize

Number of pending read requests.

pub fn pending_writes(&self) -> usize

Number of pending write requests.

pub fn tick(&mut self)

Advance the internal clock by one tick.

pub fn current_tick(&self) -> u64

Return the current tick value.

pub fn expired_requests(&self) -> Vec<&IORequest>

References to pending requests whose deadline has passed.

pub fn drain_expired(&mut self) -> Vec<IORequest>

Remove and return all pending requests whose deadline has passed.

pub fn stats(&self) -> IOSchedulerStats

Snapshot of current scheduler statistics.

pub fn config(&self) -> &SchedulerConfig

Borrow the scheduler configuration.