recv_match(pred) scans the queue front-to-back, removes and returns the
first match (rest preserved in arrival order), and parks/re-scans on every
send when nothing matches — a selective receiver may park on a non-empty
queue. Returns Err only once the channel is closed with no queued match.
try_recv_match is the non-blocking variant, mirroring try_recv.
Sender::drop now wakes the parked receiver on the last-sender drop
regardless of queue emptiness, so a selective receiver parked on a
non-empty no-match queue observes closure instead of sleeping forever.
No-op for plain recv (which only ever parks on an empty queue).
Add `Config::alloc_interval()` and `Config::timeslice_cycles()` so
callers can tune preemption sensitivity at runtime. The values flow
through `RuntimeInner` and are written into per-scheduler-thread locals
via a new `configure_preempt()` call at thread startup, keeping the hot
path free of cross-thread coherency traffic.
Fix unused-variable warnings in channel.rs by inlining `current_pid()`
directly into `te!` macro arguments — since the no-op macro arm never
evaluates its argument, no binding is needed at the call site.
Clean up a handful of dead imports exposed by the refactor.
Hand-rolled context switching on mmap'd stacks with guard pages,
allocator-driven RDTSC preemption, unbounded MPSC channels, supervision
via per-slot Signal mailboxes, root supervisor as sentinel PID.
Lib + tests + benches clean check/clippy. All 29 tests pass.
Bench: smarm 3.4% over serial baseline, within 160us of tokio
current-thread on prime-counting fan-out.
smarm-dev