[XPU] Register KV offload mmap region as pinned host memory - #51956
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[XPU] Register KV offload mmap region as pinned host memory#51956chaojun-zhang wants to merge 2 commits into
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Adds vllm/v1/kv_offload/cpu/host_register.py, a platform-dispatching host_register/host_unregister helper for CPU KV-cache offload. On CUDA/ROCm it wraps the existing cudaHostRegister/cudaHostUnregister calls (moved out of gpu_worker.py/shared_offload_region.py verbatim); on XPU it calls the new torch.ops._C.xpu_host_register/ xpu_host_unregister custom ops (see vllm-project/vllm-xpu-kernels#519) so the shared mmap KV-offload region can be pinned for direct DMA on Intel GPUs as well, instead of falling back to unpinned/pageable transfers. CPUOffloadingSpec._uses_shared_region now also returns True for XPU so the shared-mmap replicated-layout path (and therefore host registration) is used on that platform too. Signed-off-by: Chaojun Zhang <chaojun.zhang@intel.com>
Mirror the CUDA branch's logger.warning on cudaHostRegister/ cudaHostUnregister failure by also warning when the XPU xpu_host_register/xpu_host_unregister ops report failure, instead of silently swallowing it. Signed-off-by: Chaojun Zhang <chaojun.zhang@intel.com>
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Summary
Extends the CPU KV-cache offloading path's mmap host registration to Intel XPU, and factors the CUDA/ROCm
cudaHostRegister/cudaHostUnregistercalls out into a small platform-dispatching helper module.Dependency
vllm-project/vllm-xpu-kernels#519 (
xpu_host_register/xpu_host_unregisterops).