Fix lifetime management for sycl event

numba_dpex/core/datamodel/models.py

@@ -172,8 +172,8 @@ class SyclEventModel(StructModel):
     def __init__(self, dmm, fe_type):
         members = [
             (
-                "parent",
-                types.CPointer(types.int8),
+                "meminfo",
+                types.MemInfoPointer(types.pyobject),
             ),
             (
                 "event_ref",

numba_dpex/core/runtime/_dpexrt_python.c

@@ -24,6 +24,8 @@
 #include "_queuestruct.h"
 #include "_usmarraystruct.h"
 
+#include "numba/core/runtime/nrt_external.h"
+
 // forward declarations
 static struct PyUSMArrayObject *PyUSMNdArray_ARRAYOBJ(PyObject *obj);
 static npy_intp product_of_shape(npy_intp *shape, npy_intp ndim);
@@ -64,9 +66,12 @@ DPEXRT_sycl_usm_ndarray_to_python_acqref(usmarystruct_t *arystruct,
                                          PyArray_Descr *descr);
 static int DPEXRT_sycl_queue_from_python(PyObject *obj,
                                          queuestruct_t *queue_struct);
-static int DPEXRT_sycl_event_from_python(PyObject *obj,
+static int DPEXRT_sycl_event_from_python(NRT_api_functions *nrt,
+                                         PyObject *obj,
                                          eventstruct_t *event_struct);
 static PyObject *DPEXRT_sycl_queue_to_python(queuestruct_t *queuestruct);
+static PyObject *DPEXRT_sycl_event_to_python(NRT_api_functions *nrt,
+                                             eventstruct_t *eventstruct);
 
 /** An NRT_external_malloc_func implementation using DPCTLmalloc_device.
  *
@@ -1306,7 +1311,8 @@ static PyObject *DPEXRT_sycl_queue_to_python(queuestruct_t *queuestruct)
  *                          represent a dpctl.SyclEvent inside Numba.
  * @return   {return}       Return code indicating success (0) or failure (-1).
  */
-static int DPEXRT_sycl_event_from_python(PyObject *obj,
+static int DPEXRT_sycl_event_from_python(NRT_api_functions *nrt,
+                                         PyObject *obj,
                                          eventstruct_t *event_struct)
 {
     struct PySyclEventObject *event_obj = NULL;
@@ -1328,7 +1334,13 @@ static int DPEXRT_sycl_event_from_python(PyObject *obj,
         goto error;
     }
 
-    event_struct->parent = obj;
+    // We are doing incref here to ensure python does not release the object
+    // while NRT references it. Coresponding decref is called by NRT in
+    // NRT_MemInfo_pyobject_dtor once there is no reference to this object by
+    // the code managed by NRT.
+    Py_INCREF(event_obj);
+    event_struct->meminfo =
+        nrt->manage_memory(event_obj, NRT_MemInfo_pyobject_dtor);
     event_struct->event_ref = event_ref;
 
     return 0;
@@ -1355,12 +1367,13 @@ static int DPEXRT_sycl_event_from_python(PyObject *obj,
  * @return   {return}       A PyObject created from the eventstruct->parent, if
  *                          the PyObject could not be created return NULL.
  */
-static PyObject *DPEXRT_sycl_event_to_python(eventstruct_t *eventstruct)
+static PyObject *DPEXRT_sycl_event_to_python(NRT_api_functions *nrt,
+                                             eventstruct_t *eventstruct)
 {
     PyObject *orig_event = NULL;
     PyGILState_STATE gstate;
 
-    orig_event = eventstruct->parent;
+    orig_event = nrt->get_data(eventstruct->meminfo);
     // FIXME: Better error checking is needed to enforce the boxing of the event
     // object. For now, only the minimal is done as the returning of SyclEvent
     // from a dpjit function should not be a used often and the dpctl C API for
@@ -1375,9 +1388,13 @@ static PyObject *DPEXRT_sycl_event_to_python(eventstruct_t *eventstruct)
     DPEXRT_DEBUG(
         drt_debug_print("DPEXRT-DEBUG: In DPEXRT_sycl_event_to_python.\n"););
 
+    // TODO: is there any way to release meminfo without calling dtor so we dont
+    //  call incref, decref one after another.
     // We need to increase reference count because we are returning new
     // reference to the same event.
     Py_INCREF(orig_event);
+    // We need to release meminfo since we are taking ownership back.
+    nrt->release(eventstruct->meminfo);
 
     return orig_event;
 }

numba_dpex/core/runtime/_eventstruct.h

@@ -11,10 +11,10 @@
 
 #pragma once
 
-#include <Python.h>
+#include "numba/core/runtime/nrt_external.h"
 
 typedef struct
 {
-    PyObject *parent;
+    NRT_MemInfo *meminfo;
     void *event_ref;
 } eventstruct_t;

numba_dpex/core/runtime/_nrt_helper.c

@@ -134,3 +134,15 @@ void NRT_MemInfo_destroy(NRT_MemInfo *mi)
         TheMSys.stats.mi_free++;
     }
 }
+
+void NRT_MemInfo_pyobject_dtor(void *data)
+{
+    PyGILState_STATE gstate;
+    PyObject *ownerobj = data;
+
+    gstate = PyGILState_Ensure(); /* ensure the GIL */
+    Py_DECREF(data);              /* release the python object */
+    PyGILState_Release(gstate);   /* release the GIL */
+
+    DPEXRT_DEBUG(drt_debug_print("DPEXRT-DEBUG: pyobject destructor\n"););
+}

numba_dpex/core/runtime/_nrt_helper.h

@@ -19,5 +19,6 @@ size_t NRT_MemInfo_refcount(NRT_MemInfo *mi);
 void NRT_Free(void *ptr);
 void NRT_dealloc(NRT_MemInfo *mi);
 void NRT_MemInfo_destroy(NRT_MemInfo *mi);
+void NRT_MemInfo_pyobject_dtor(void *data);
 
 #endif /* _NRT_HELPER_H_ */

numba_dpex/core/runtime/context.py

@@ -4,6 +4,7 @@
 
 import functools
 
+import numba.core.unsafe.nrt
 from llvmlite import ir as llvmir
 from numba.core import cgutils, types
 
@@ -206,26 +207,32 @@ def queuestruct_to_python(self, pyapi, val):
     def eventstruct_from_python(self, pyapi, obj, ptr):
         """Calls the c function DPEXRT_sycl_event_from_python"""
         fnty = llvmir.FunctionType(
-            llvmir.IntType(32), [pyapi.pyobj, pyapi.voidptr]
+            llvmir.IntType(32), [pyapi.voidptr, pyapi.pyobj, pyapi.voidptr]
         )
+        nrt_api = self._context.nrt.get_nrt_api(pyapi.builder)
 
         fn = pyapi._get_function(fnty, "DPEXRT_sycl_event_from_python")
         fn.args[0].add_attribute("nocapture")
         fn.args[1].add_attribute("nocapture")
+        fn.args[2].add_attribute("nocapture")
 
-        self.error = pyapi.builder.call(fn, (obj, ptr))
+        self.error = pyapi.builder.call(fn, (nrt_api, obj, ptr))
         return self.error
 
     def eventstruct_to_python(self, pyapi, val):
         """Calls the c function DPEXRT_sycl_event_to_python"""
 
-        fnty = llvmir.FunctionType(pyapi.pyobj, [pyapi.voidptr])
+        fnty = llvmir.FunctionType(pyapi.pyobj, [pyapi.voidptr, pyapi.voidptr])
+        nrt_api = self._context.nrt.get_nrt_api(pyapi.builder)
 
         fn = pyapi._get_function(fnty, "DPEXRT_sycl_event_to_python")
         fn.args[0].add_attribute("nocapture")
+        fn.args[1].add_attribute("nocapture")
+
         qptr = cgutils.alloca_once_value(pyapi.builder, val)
         ptr = pyapi.builder.bitcast(qptr, pyapi.voidptr)
-        self.error = pyapi.builder.call(fn, [ptr])
+
+        self.error = pyapi.builder.call(fn, [nrt_api, ptr])
 
         return self.error
 

numba_dpex/dpctl_iface/libsyclinterface_bindings.py

@@ -71,7 +71,7 @@ def dpctl_event_wait(builder: llvmir.IRBuilder, *args):
     mod = builder.module
     fn = _build_dpctl_function(
         llvm_module=mod,
-        return_ty=cgutils.voidptr_t,
+        return_ty=llvmir.VoidType(),
         arg_list=[cgutils.voidptr_t],
         func_name="DPCTLEvent_Wait",
     )
@@ -85,7 +85,7 @@ def dpctl_event_delete(builder: llvmir.IRBuilder, *args):
     mod = builder.module
     fn = _build_dpctl_function(
         llvm_module=mod,
-        return_ty=cgutils.voidptr_t,
+        return_ty=llvmir.VoidType(),
         arg_list=[cgutils.voidptr_t],
         func_name="DPCTLEvent_Delete",
     )
@@ -99,7 +99,7 @@ def dpctl_queue_delete(builder: llvmir.IRBuilder, *args):
     mod = builder.module
     fn = _build_dpctl_function(
         llvm_module=mod,
-        return_ty=cgutils.voidptr_t,
+        return_ty=llvmir.VoidType(),
         arg_list=[cgutils.voidptr_t],
         func_name="DPCTLQueue_Delete",
     )