fix(core): pre-allocate trackedRefs in pass encoders (ML OOM fix)#196
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BeginComputePass, BeginRenderPass, and CreateCommandEncoder now pre-allocate trackedRefs with capacity 64. Previously Phase 2 tracking (v0.28.8) used bare append() from nil — O(log N) reallocations with abandoned backing arrays. For 10K dispatches × 4 buffers, each encoder did 17 doublings (1→2→4→...→65536). Pre-allocation eliminates all intermediate arrays. Investigation confirmed all transfer points already nil the source: - ComputePassEncoder.End() → p.trackedRefs = nil - CommandEncoder.Finish() → e.trackedRefs = nil - postSubmit() → cb.trackedRefs = nil - DestroyQueue.Triage() → zeros TrackedSubmission struct Rust uses mem::take() (swap with empty) at transfer, Vec capacity is reused via EncoderInFlight ownership chain. Our pre-alloc achieves the same effect — single allocation per pass, no intermediate arrays.
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Summary
trackedRefswith capacity 64 inBeginComputePass,BeginRenderPass,CreateCommandEncoderappend()starting at nilInvestigation
All transfer points already nil the source correctly:
ComputePassEncoder.End()→p.trackedRefs = nil✅CommandEncoder.Finish()→e.trackedRefs = nil✅postSubmit()→cb.trackedRefs = nil✅DestroyQueue.Triage()→ zerosTrackedSubmissionstruct ✅Rust uses
mem::take()(swap with empty Vec) — Vec capacity reused viaEncoderInFlightownership. Our pre-alloc achieves same effect.Test plan