Add devdax memory provider

Signed-off-by: Lukasz Dorau <[email protected]>

Author: ldorau

CMakeLists.txt

@@ -419,6 +419,9 @@ endif()
 
 if(NOT UMF_DISABLE_HWLOC)
     add_optional_symbol(umfOsMemoryProviderOps)
+    if(LINUX)
+        add_optional_symbol(umfDevDaxMemoryProviderOps)
+    endif()
 endif()
 
 add_subdirectory(src)

README.md

@@ -172,6 +172,22 @@ Additionally, required for tests:
 5) Required packages:
    - liblevel-zero-dev (Linux) or level-zero-sdk (Windows)
 
+#### DevDax memory provider (Linux only)
+
+A memory provider that provides memory from a device DAX (a character device file /dev/daxX.Y).
+It can be used when large memory mappings are needed.
+
+The DevDax memory provider does not support the free operation
+(`umfMemoryProviderFree()` always returns `UMF_RESULT_ERROR_NOT_SUPPORTED`),
+so it should be used with a pool manager that will take over
+the managing of the provided memory - for example the jemalloc pool
+with the `disable_provider_free` parameter set to true.
+
+##### Requirements
+
+1) Linux OS
+2) A character device file /dev/daxX.Y created in the OS.
+
 ### Memory pool managers
 
 #### Proxy pool (part of libumf)

include/umf/providers/provider_devdax_memory.h

@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2024 Intel Corporation
+ *
+ * Under the Apache License v2.0 with LLVM Exceptions. See LICENSE.TXT.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+*/
+
+#ifndef UMF_DEVDAX_MEMORY_PROVIDER_H
+#define UMF_DEVDAX_MEMORY_PROVIDER_H
+
+#include <umf/providers/provider_os_memory.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/// @cond
+#define UMF_DEVDAX_RESULTS_START_FROM 2000
+/// @endcond
+
+/// @brief Memory provider settings struct
+typedef struct umf_devdax_memory_provider_params_t {
+    /// path of the device DAX
+    char *path;
+    /// size of the device DAX in bytes
+    size_t size;
+    /// combination of 'umf_mem_protection_flags_t' flags
+    unsigned protection;
+} umf_devdax_memory_provider_params_t;
+
+/// @brief Devdax Memory Provider operation results
+typedef enum umf_devdax_memory_provider_native_error {
+    UMF_DEVDAX_RESULT_SUCCESS = UMF_DEVDAX_RESULTS_START_FROM, ///< Success
+    UMF_DEVDAX_RESULT_ERROR_ALLOC_FAILED,        ///< Memory allocation failed
+    UMF_DEVDAX_RESULT_ERROR_ADDRESS_NOT_ALIGNED, ///< Allocated address is not aligned
+    UMF_DEVDAX_RESULT_ERROR_FREE_FAILED,         ///< Memory deallocation failed
+    UMF_DEVDAX_RESULT_ERROR_PURGE_FORCE_FAILED, ///< Force purging failed
+} umf_devdax_memory_provider_native_error_t;
+
+umf_memory_provider_ops_t *umfDevDaxMemoryProviderOps(void);
+
+/// @brief Create default params for the devdax memory provider
+static inline umf_devdax_memory_provider_params_t
+umfDevDaxMemoryProviderParamsDefault(char *path, size_t size) {
+    umf_devdax_memory_provider_params_t params = {
+        path, /* path of the device DAX */
+        size, /* size of the device DAX in bytes */
+        UMF_PROTECTION_READ | UMF_PROTECTION_WRITE, /* protection */
+    };
+
+    return params;
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* UMF_DEVDAX_MEMORY_PROVIDER_H */

scripts/docs_config/api.rst

@@ -96,6 +96,14 @@ A memory provider that provides memory from L0 device.
 .. doxygenfile:: provider_level_zero.h
     :sections: define enum typedef func var
 
+DevDax Memory Provider
+------------------------------------------
+
+A memory provider that provides memory from a device DAX (a character device file /dev/daxX.Y).
+
+.. doxygenfile:: provider_devdax_memory.h
+    :sections: define enum typedef func var
+
 Memspace
 ==========================================
 

src/CMakeLists.txt

@@ -101,6 +101,7 @@ set(UMF_SOURCES_MACOSX libumf_linux.c)
 set(UMF_SOURCES_WINDOWS libumf_windows.c)
 
 set(UMF_SOURCES_COMMON_LINUX_MACOSX
+    provider/provider_devdax_memory.c
     provider/provider_os_memory.c
     provider/provider_os_memory_posix.c
     memtargets/memtarget_numa.c