add MKLMemory object, backed with mkl_malloc memory

exposes Python buffer protocol

Author: ndgrigorian

meson.build

@@ -43,7 +43,7 @@ py.extension_module(
     subdir: 'mkl'
 )
 
-# Cython extension
+# Cython extensions
 py.extension_module(
     '_py_mkl_service',
     sources: ['mkl/_py_mkl_service.pyx'],
@@ -54,6 +54,17 @@ py.extension_module(
     subdir: 'mkl'
 )
 
+py.extension_module(
+    '_mkl_memory',
+    sources: ['mkl/_mkl_memory.pyx'],
+    dependencies: [mkl_dep],
+    c_args: c_args,
+    install_rpath: rpath,
+    install: true,
+    subdir: 'mkl'
+)
+
+
 # Python sources
 py.install_sources(
     [

mkl/__init__.py

@@ -57,6 +57,7 @@ def __exit__(self, *args):
 del RTLD_for_MKL
 del sys
 
+from ._mkl_memory import MKLMemory
 from ._py_mkl_service import *
 from ._version import __version__
 

mkl/_mkl_memory.pyx

@@ -0,0 +1,104 @@
+# Copyright (c) 2018, Intel Corporation
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+#     * Redistributions of source code must retain the above copyright notice,
+#       this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above copyright
+#       notice, this list of conditions and the following disclaimer in the
+#       documentation and/or other materials provided with the distribution.
+#     * Neither the name of Intel Corporation nor the names of its contributors
+#       may be used to endorse or promote products derived from this software
+#       without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+# distutils: language = c
+# cython: language_level=3
+
+import numbers
+
+from cpython cimport Py_buffer
+from libc.string cimport memcpy
+
+from mkl._mkl_service cimport mkl_malloc, mkl_free
+
+
+cdef class MKLMemory:
+    cdef void *_memory_ptr
+    cdef Py_ssize_t nbytes
+
+    cdef _cinit_empty(self):
+        self._memory_ptr = NULL
+        self.nbytes = 0
+
+    cdef _cinit_alloc(self, Py_ssize_t nbytes, Py_ssize_t alignment):
+        self._cinit_empty()
+
+        if (nbytes > 0):
+            with nogil:
+                p = mkl_malloc(nbytes, alignment)
+
+            if (p):
+                self._memory_ptr = p
+                self.nbytes = nbytes
+            else:
+                raise MemoryError(
+                    "MKL memory allocation failed."
+                )
+        else:
+            raise ValueError(
+                "Number of bytes of request allocation must be positive."
+            )
+
+    cdef _cinit_other(self, object other, Py_ssize_t alignment):
+        cdef MKLMemory other_mem
+        if isinstance(other, MKLMemory):
+            other_mem = <MKLMemory> other
+        else:
+            raise ValueError(
+                f"Argument {other} is not of type MKLMemory."
+            )
+        self._cinit_alloc(other_mem.nbytes, alignment)
+        with nogil:
+            memcpy(self._memory_ptr, other_mem._memory_ptr, self.nbytes)
+
+    def __cinit__(self, other, *, Py_ssize_t alignment=64):
+        if isinstance(other, numbers.Integral):
+            self._cinit_alloc(other, alignment)
+        else:
+            self._cinit_other(other, alignment)
+
+    def __dealloc__(self):
+        if not (self._memory_ptr is NULL):
+            mkl_free(self._memory_ptr)
+        self._cinit_empty()
+
+    cdef void *get_data_ptr(self):
+        return self._memory_ptr
+
+    def __getbuffer__(self, Py_buffer *buffer, int flags):
+        buffer.buf = <void *>self._memory_ptr
+        buffer.format = "B"                     # byte
+        buffer.internal = NULL                  # see References
+        buffer.itemsize = 1
+        buffer.len = self.nbytes
+        buffer.ndim = 1
+        buffer.obj = self
+        buffer.readonly = 0
+        buffer.shape = &self.nbytes
+        buffer.strides = &buffer.itemsize
+        buffer.suboffsets = NULL                # for pointer arrays only
+
+    def __releasebuffer__(self, Py_buffer *buffer):
+        pass

mkl/_mkl_service.pxd

@@ -151,6 +151,8 @@ cdef extern from "mkl.h":
     MKL_INT64 mkl_mem_stat(int* buf)
     MKL_INT64 mkl_peak_mem_usage(int mode)
     int mkl_set_memory_limit(int mem_type, size_t limit)
+    void *mkl_malloc(size_t size, int alignment) nogil
+    void mkl_free(void *ptr) nogil
 
     # Conditional Numerical Reproducibility
     int mkl_cbwr_set(int settings)