Don't presume pointers are mutually exclusive for device/host. #6128
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robertmaynard
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Here is the results of looking at the cudaPointerGetAttributes of different allocation types. As we can see things like cudaMallocManaged allow the same pointer to be both host and device. ``` cudaPointerGetAttributes attributes integer is_dev_ptr -> 0 is_host_ptr -> 0 cudaPointerGetAttributes attributes std::vector<int> data is_dev_ptr -> 0 is_host_ptr -> 0 cudaPointerGetAttributes attributes malloc ptr is_dev_ptr -> 0 is_host_ptr -> 0 cudaPointerGetAttributes attributes cudaMalloc ptr is_dev_ptr -> 1 is_host_ptr -> 0 cudaPointerGetAttributes attributes cudaMallocManaged cudaMemAttachGlobal ptr is_dev_ptr -> 1 is_host_ptr -> 1 cudaPointerGetAttributes attributes cudaMallocManaged cudaMemAttachHost ptr is_dev_ptr -> 1 is_host_ptr -> 1 cudaPointerGetAttributes attributes cudaMallocHost ptr is_dev_ptr -> 1 is_host_ptr -> 1 ```
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Currently running some more manual validation checks |
robertmaynard
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5 - DO NOT MERGE
wphicks
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Nov 5, 2024
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/merge |
divyegala
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Nov 6, 2024
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A pointer can be usable on the device and host at the same time. We can't invert
is_dev_ptr()to check that something is a host pointer.Here is the results of looking at the cudaPointerGetAttributes of different allocation types. As we can see things like cudaMallocManaged and cudaMallocHost allow the same pointer to be both host and device.