Cycles: Always use guarded allocator of vectors

We don't have vectors re-allocation happening multiple times from inside
a loop anymore, so we can safely switch to a memory guarded allocator for
vectors and keep track on the memory usage at various stages of rendering.

Additionally, when building from inside Blender repository, Cycles will
use Blender's guarded allocator, so actual memory usage will be displayed
in the Space Info header.

There are couple of tricky aspects of the patch:

- TaskScheduler::exit() now explicitly frees memory used by `threads`.
  This is needed because `threads` is a static member which destructor
  isn't getting called on Blender's exit which caused memory leak print
  to happen.

  This shouldn't give any measurable speed issues, reallocation of that
  vector is only one of fewzillion other allocations happening during
  synchronization.

- Use regular guarded malloc (not aligned one). No idea why it was
  made to be aligned in the first place. Perhaps some corner case tests
  or so. Vector was never expected to be aligned anyway. Let's see if
  we'll have actual bugs with this.

Reviewers: dingto, lukasstockner97, juicyfruit, brecht

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D1774

intern/cycles/blender/blender_python.cpp

@@ -39,6 +39,10 @@ CCL_NAMESPACE_BEGIN
 
 namespace {
 
+/* Device list stored static (used by compute_device_list()). */
+static ccl::vector<CCLDeviceInfo> device_list;
+static ccl::DeviceType device_type = DEVICE_NONE;
+
 /* Flag describing whether debug flags were synchronized from scene. */
 bool debug_flags_set = false;
 
@@ -172,6 +176,16 @@ static PyObject *init_func(PyObject * /*self*/, PyObject *args)
 	Py_RETURN_NONE;
 }
 
+
+static PyObject *exit_func(PyObject * /*self*/, PyObject * /*args*/)
+{
+	ShaderManager::free_memory();
+	TaskScheduler::free_memory();
+	Device::free_memory();
+	device_list.free_memory();
+	Py_RETURN_NONE;
+}
+
 static PyObject *create_func(PyObject * /*self*/, PyObject *args)
 {
 	PyObject *pyengine, *pyuserpref, *pydata, *pyscene, *pyregion, *pyv3d, *pyrv3d;
@@ -616,6 +630,7 @@ static PyObject *debug_flags_reset_func(PyObject * /*self*/, PyObject * /*args*/
 
 static PyMethodDef methods[] = {
 	{"init", init_func, METH_VARARGS, ""},
+	{"exit", exit_func, METH_VARARGS, ""},
 	{"create", create_func, METH_VARARGS, ""},
 	{"free", free_func, METH_O, ""},
 	{"render", render_func, METH_O, ""},
@@ -648,10 +663,6 @@ static struct PyModuleDef module = {
 
 static CCLDeviceInfo *compute_device_list(DeviceType type)
 {
-	/* device list stored static */
-	static ccl::vector<CCLDeviceInfo> device_list;
-	static ccl::DeviceType device_type = DEVICE_NONE;
-
 	/* create device list if it's not already done */
 	if(type != device_type) {
 		ccl::vector<DeviceInfo>& devices = ccl::Device::available_devices();