[SYCL][L0] Fix memory leak in event pool.

sycl/plugins/level_zero/pi_level_zero.cpp

@@ -437,6 +437,26 @@ pi_result _pi_context::initialize() {
   return PI_SUCCESS;
 }
 
+pi_result _pi_context::finalize() {
+  // This function is called when pi_context is deallocated, piContextRelase.
+  // There could be some memory that may have not been deallocated.
+  // For example, zeEventPool could be still alive.
+  std::lock_guard<std::mutex> NumEventsLiveInEventPoolGuard(
+      NumEventsLiveInEventPoolMutex, std::adopt_lock);
+  if (ZeEventPool && NumEventsLiveInEventPool[ZeEventPool])
+    zeEventPoolDestroy(ZeEventPool);
+
+  // Destroy the command list used for initializations
+  ZE_CALL(zeCommandListDestroy(ZeCommandListInit));
+
+  // Destruction of some members of pi_context uses L0 context
+  // and therefore it must be valid at that point.
+  // Technically it should be placed to the destructor of pi_context
+  // but this makes API error handling more complex.
+  ZE_CALL(zeContextDestroy(ZeContext));
+  return PI_SUCCESS;
+}
+
 pi_result
 _pi_queue::resetCommandListFenceEntry(ze_command_list_handle_t ZeCommandList,
                                       bool MakeAvailable) {
@@ -1810,16 +1830,10 @@ pi_result piContextRelease(pi_context Context) {
 
   assert(Context);
   if (--(Context->RefCount) == 0) {
-    auto ZeContext = Context->ZeContext;
-    // Destroy the command list used for initializations
-    ZE_CALL(zeCommandListDestroy(Context->ZeCommandListInit));
+    // Clean up any live memory associated with Context
+    pi_result Result = Context->finalize();
     delete Context;
-
-    // Destruction of some members of pi_context uses L0 context
-    // and therefore it must be valid at that point.
-    // Technically it should be placed to the destructor of pi_context
-    // but this makes API error handling more complex.
-    ZE_CALL(zeContextDestroy(ZeContext));
+    return Result;
   }
   return PI_SUCCESS;
 }

sycl/plugins/level_zero/pi_level_zero.hpp

@@ -216,6 +216,9 @@ struct _pi_context : _pi_object {
   // Initialize the PI context.
   pi_result initialize();
 
+  // Finalize the PI context
+  pi_result finalize();
+
   // A L0 context handle is primarily used during creation and management of
   // resources that may be used by multiple devices.
   ze_context_handle_t ZeContext;