!2367 enlarge memory to support bert large pretraining with 96 bs

Merge pull request !2367 from yoonlee666/edit-example

model_zoo/bert/run_pretrain.py

@@ -81,7 +81,7 @@ def run_pretrain():
     args_opt = parser.parse_args()
     context.set_context(mode=context.GRAPH_MODE, device_target=args_opt.device_target, device_id=args_opt.device_id)
     context.set_context(reserve_class_name_in_scope=False)
-
+    context.set_context(variable_memory_max_size="30GB")
     ckpt_save_dir = args_opt.save_checkpoint_path
     if args_opt.distribute == "true":
         if args_opt.device_target == 'Ascend':