Cold-path constructor sites (2):
- portfolio_states init: htod_f32 → upload_f32_via_pinned
- rng_states init: memcpy_htod → upload_u32_via_pinned
Warm per-collect sites (2):
- episode_starts_buf: memcpy_htod → upload_i32_via_pinned
- barrier_config: htod_f32 → upload_f32_via_pinned
Warm per-epoch reset (2 sites + persistent staging refactor):
The Vec<f32>/Vec<u32> host staging fields (portfolio_init_staging,
rng_seed_staging) replaced with persistent MappedF32Buffer /
MappedU32Buffer allocated once at construction. Resets fill via
host_slice_mut() (zero-allocation, zero-HtoD); a single async DtoD
seeds the persistent device-resident portfolio_states / rng_states
(which the kernel mutates each step and must remain in VRAM).
Adds host_slice_mut() accessor on MappedF32Buffer and MappedU32Buffer
to support structured per-element writes against the mapped pages.
Audit row appended (Fix 11) in docs/dqn-gpu-hot-path-audit.md.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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