From 9e636236ca99ae14f4a5481fa4b6181ef95d9dbc Mon Sep 17 00:00:00 2001
From: Ajit Mistry <mail@a-mistry.com>
Date: Fri, 6 Sep 2024 21:23:56 +0000
Subject: [PATCH] .

---
 cpp/include/cuvs/core/c_api.h | 16 ++++++++++++++++
 cpp/src/core/c_api.cpp        | 16 ++++++++++++++++
 cpp/test/core/c_api.c         |  9 +++++++++
 3 files changed, 41 insertions(+)

diff --git a/cpp/include/cuvs/core/c_api.h b/cpp/include/cuvs/core/c_api.h
index 4db7fd12c..47d40db2f 100644
--- a/cpp/include/cuvs/core/c_api.h
+++ b/cpp/include/cuvs/core/c_api.h
@@ -148,6 +148,22 @@ cuvsError_t cuvsRMMPoolMemoryResourceEnable(int initial_pool_size_percent,
  */
 cuvsError_t cuvsRMMMemoryResourceReset();
 
+/**
+ * @brief Allocates pinned memory on the host using RMM
+ * @param[out] ptr Pointer to allocated host memory
+ * @param[in] bytes Size in bytes to allocate
+ * @return cuvsError_t
+ */
+cuvsError_t cuvsRMMHostAlloc(void** ptr, size_t bytes);
+
+/**
+ * @brief Deallocates pinned memory on the host using RMM
+ * @param[in] ptr Pointer to allocated host memory to free
+ * @param[in] bytes Size in bytes to deallocate
+ * @return cuvsError_t
+ */
+cuvsError_t cuvsRMMHostFree(void* ptr, size_t bytes);
+
 /** @} */
 
 #ifdef __cplusplus
diff --git a/cpp/src/core/c_api.cpp b/cpp/src/core/c_api.cpp
index a75e5a1dd..d2b3262a1 100644
--- a/cpp/src/core/c_api.cpp
+++ b/cpp/src/core/c_api.cpp
@@ -23,6 +23,7 @@
 #include <rmm/cuda_stream_view.hpp>
 #include <rmm/mr/device/per_device_resource.hpp>
 #include <rmm/mr/device/pool_memory_resource.hpp>
+#include <rmm/mr/host/pinned_memory_resource.hpp>
 #include <thread>
 
 extern "C" cuvsError_t cuvsResourcesCreate(cuvsResources_t* res)
@@ -111,6 +112,21 @@ extern "C" cuvsError_t cuvsRMMMemoryResourceReset()
   });
 }
 
+thread_local std::unique_ptr<rmm::mr::pinned_memory_resource> pinned_mr;
+
+extern "C" cuvsError_t cuvsRMMHostAlloc(void** ptr, size_t bytes)
+{
+  return cuvs::core::translate_exceptions([=] {
+    if (pinned_mr == nullptr) { pinned_mr = std::make_unique<rmm::mr::pinned_memory_resource>(); }
+    *ptr = pinned_mr->allocate(bytes);
+  });
+}
+
+extern "C" cuvsError_t cuvsRMMHostFree(void* ptr, size_t bytes)
+{
+  return cuvs::core::translate_exceptions([=] { pinned_mr->deallocate(ptr, bytes); });
+}
+
 thread_local std::string last_error_text = "";
 
 extern "C" const char* cuvsGetLastErrorText()
diff --git a/cpp/test/core/c_api.c b/cpp/test/core/c_api.c
index 27973c2dd..f83e1d49d 100644
--- a/cpp/test/core/c_api.c
+++ b/cpp/test/core/c_api.c
@@ -58,6 +58,15 @@ int main()
   cuvsError_t reset_error = cuvsRMMMemoryResourceReset();
   if (reset_error == CUVS_ERROR) { exit(EXIT_FAILURE); }
 
+  // Alloc memory on host (pinned)
+  void* ptr3;
+  cuvsError_t alloc_error_pinned = cuvsRMMHostAlloc(&ptr3, 1024);
+  if (alloc_error_pinned == CUVS_ERROR) { exit(EXIT_FAILURE); }
+
+  // Free memory
+  cuvsError_t free_error_pinned = cuvsRMMHostFree(ptr3, 1024);
+  if (free_error_pinned == CUVS_ERROR) { exit(EXIT_FAILURE); }
+
   // Destroy resources
   cuvsError_t destroy_error = cuvsResourcesDestroy(res);
   if (destroy_error == CUVS_ERROR) { exit(EXIT_FAILURE); }