Report host_numa virtual memory as host-accessible - #2503
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Andy-Jost merged 1 commit intoAug 7, 2026
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`VirtualMemoryResource.__init__` classifies "host", "host_numa" and "host_numa_current" all as host-located (it clears `self.device` for each), but `is_host_accessible` compared with `== "host"`. A resource configured with `location_type="host_numa"` or `"host_numa_current"` therefore reported `is_host_accessible is False` *and* `is_device_accessible is False` -- an impossible answer that propagates to `Buffer.is_host_accessible`, which forwards to the memory resource. Share a single `_HOST_LOCATION_TYPES` set between the constructor and the property so the two classifications cannot drift again.
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/ok to test 5da1f5e |
Andy-Jost
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Aug 7, 2026
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A
VirtualMemoryResourceconfigured withlocation_type="host_numa"or"host_numa_current"reportsis_host_accessible is Falseandis_device_accessible is False— it claims the memory is reachable from nowhere.__init__classifies host-located resources with a substring test:but
is_host_accessibleused exact equality:Both were introduced in cec0efb (#2016) and disagreed from the start. The answer propagates to
Buffer.is_host_accessible, which forwards straight to the memory resource, so anything choosing CPU vs GPU from a buffer — DLPack/StridedMemoryViewdevice selection, copy validation — sees the wrong answer.host_numa_currentis a working configuration today: the driver ignoreslocation.idfor that type, so the resource allocates fine and only the reported accessibility is wrong.The fix gives both sites a shared
_HOST_LOCATION_TYPESfrozenset so they cannot drift again.VirtualMemoryLocationTypeis aStrEnum, so membership behaves identically for raw strings and enum members.is_device_accessibleis deliberately left alone.On verification, plainly: I have no GPU and no
cuda.bindingsbuild here, so nothing undercuda_core/tests/can even import and I did not run the new test. What I did run is the old and new expressions plus__init__'s classifier extracted against a verbatim copy of the enum — that reproduces both NUMA types returning False on both properties before the change, and agreement with__init__for all four members after. The regression test is GPU-gated by construction and will fail onmainfor the two NUMA parameters.NOTE: developed with the assistance of an AI coding agent. The new test carries
@pytest.mark.agent_authoredper AGENTS.md. I reviewed and verified the change before submitting.