Fix host view for mnnvl

cpp/include/wholememory/wholememory.h

@@ -387,6 +387,12 @@ wholememory_error_code_t wholememory_store_to_file(wholememory_handle_t wholemem
                                                    size_t file_entry_size,
                                                    const char* local_file_name);
 
+/**
+ * @param comm : WholeMemory Comm
+ * @return : bool
+ */
+bool wholememory_is_intranode_communicator(wholememory_comm_t comm);
+
 bool wholememory_is_build_with_nvshmem();
 #ifdef WITH_NVSHMEM_SUPPORT
 wholememory_error_code_t wholememory_get_nvshmem_reference(

cpp/src/wholememory/memory_handle.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019-2023, NVIDIA CORPORATION.
+ * Copyright (c) 2019-2024, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -99,6 +99,12 @@ class wholememory_impl {
     if (local_ptr != nullptr) *local_ptr = local_partition_memory_pointer_;
     if (local_size != nullptr) *local_size = rank_partition_strategy_.local_mem_size;
     if (local_offset != nullptr) *local_offset = rank_partition_strategy_.local_mem_offset;
+    if (location_ == WHOLEMEMORY_ML_HOST && (type_ == WHOLEMEMORY_MT_CONTINUOUS) &&
+        (!(comm_->is_intranode()))) {
+      WHOLEMEMORY_WARN(
+        " Multi-node continuous type wholememory can only be accessed by GPU threads but not CPU "
+        "threads, regardless of whether the location of wholememory is host.");
+    }
   }
   virtual bool get_rank_memory(void** rank_memory_ptr,
                                size_t* rank_memory_size,

cpp/src/wholememory/wholememory.cpp

@@ -261,6 +261,11 @@ wholememory_error_code_t wholememory_load_from_hdfs_file(wholememory_handle_t wh
   return WHOLEMEMORY_NOT_IMPLEMENTED;
 }
 
+bool wholememory_is_intranode_communicator(wholememory_comm_t comm)
+{
+  return wholememory::is_intranode_communicator(comm);
+}
+
 bool wholememory_is_build_with_nvshmem()
 {
 #ifdef WITH_NVSHMEM_SUPPORT

python/pylibwholegraph/pylibwholegraph/binding/wholememory_binding.pyx

@@ -184,7 +184,7 @@ cdef extern from "wholememory/wholememory.h":
 
     cdef wholememory_distributed_backend_t wholememory_communicator_get_distributed_backend(
                                                                             wholememory_comm_t comm)
-
+    cdef bool wholememory_is_intranode_communicator(wholememory_comm_t comm)
 
 cpdef enum WholeMemoryErrorCode:
     Success = WHOLEMEMORY_SUCCESS
@@ -1113,6 +1113,10 @@ cdef class PyWholeMemoryFlattenDlpack:
         cdef wholememory_comm_t comm
         cdef int world_rank
         cdef int world_size
+        if self.device_type == MlHost and mem_type == MtContinuous:
+            check_wholememory_error_code(wholememory_get_communicator(&comm, handle.wholememory_handle))
+            if wholememory_is_intranode_communicator(comm) == False :
+                raise ValueError('Multi-node continuous type wholememory does not support host_view. Only supports host_view=false regardless of whether location is host or not.')
         global_size = wholememory_get_total_size(handle.wholememory_handle)
         if global_size % elt_size != 0:
             raise ValueError('global_size=%d not multiple of elt_size=%d' % (global_size, elt_size))