fix(cuda.bindings): Make param_packer.feed() free-threading-safe via import-time init#2417
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fix(cuda.bindings): Make param_packer.feed() free-threading-safe via import-time init#2417clin1234 wants to merge 3 commits into
clin1234 wants to merge 3 commits into
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Restructure param_packer.h so the ctypes type pointers and the feeder table are built once in a new init_param_packer(), called at module import (from utils.pxi) while single-threaded. feed() becomes a read-only lookup on a never-mutated std::map, so concurrent kernel launches from multiple host threads no longer race the map or the ctypes lazy-init -- races that were live in the cp315t (Py_MOD_GIL_NOT_USED) wheels. init_param_packer is declared 'except +' so a failed 'import ctypes' surfaces as a Python exception at import instead of std::terminate across the Cython boundary, and feed() is now non-throwing. The ctypes module strong ref is kept deliberately (it keeps the borrowed type pointers valid). Harden resource_handles.cpp: make mr_dealloc_cb std::atomic with acquire/release ordering, and document the verified single-init of initialize_deferred_cleanup() and the mutation-only lazy path for GraphBox::slot_table (both already safe; no behavior change).
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July 24, 2026 16:01
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Description
Restructure param_packer.h so the ctypes type pointers and the feeder table are built once in a new init_param_packer(), called at module import (from utils.pxi) while single-threaded. feed() becomes a read-only lookup on a never-mutated std::map, so concurrent kernel launches from multiple host threads no longer race the map or the ctypes lazy-init -- races that were live in the cp315t (Py_MOD_GIL_NOT_USED) wheels. init_param_packer is declared 'except +' so a failed 'import ctypes' surfaces as a Python exception at import instead of std::terminate across the Cython boundary, and feed() is now non-throwing. The ctypes module strong ref is kept deliberately (it keeps the borrowed type pointers valid).
Harden resource_handles.cpp: make mr_dealloc_cb std::atomic with acquire/release ordering, and document the verified single-init of initialize_deferred_cleanup() and the mutation-only lazy path for GraphBox::slot_table (both already safe; no behavior change).
closes #2416