forked from unom/punktfunk
Shared::mappings only ever grew: clear_cache reset sent_keys and told the worker to drop its fd cache, but nothing closed the host-side CUDA IPC mappings for the previous pool generation. A session that renegotiates repeatedly (mode changes, HDR toggles, client reconnects) accumulated a pool's worth of stale mappings each time, each pinning a host VA reservation to peer memory the worker had already freed. Mappings now carry a refcount and a retired flag. clear_cache closes every unreferenced mapping immediately and marks the rest retired; a retired mapping closes when its last in-flight DeviceBuffer releases. The worker's half of the contract: ClearCache also forgets its VA→id map, so anything delivered after the boundary gets a fresh id WITH its descriptor — without that, a same-shape renegotiation (worker keeps its pool) would re-deliver an old id whose host mapping was just closed, and the host would misread it as a desync. Ids never repeat (next_id only counts up), so fresh ids cannot collide with the graveyard. (R6 from design/pf-zerocopy-sweep-handoff.md.) Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>