Don't use persistable for fetched variables

BERT/run_squad.py

@@ -144,9 +144,6 @@ def create_model(pyreader_name, bert_config, is_training=False):
     batch_ones = fluid.layers.fill_constant_batch_size_like(
         input=start_logits, dtype='int64', shape=[1], value=1)
     num_seqs = fluid.layers.reduce_sum(input=batch_ones)
-    num_seqs.persistable = True
-    start_logits.persistable = True
-    end_logits.persistable = True
 
     if is_training:
 
@@ -161,7 +158,6 @@ def create_model(pyreader_name, bert_config, is_training=False):
         total_loss = (start_loss + end_loss) / 2.0
         if args.use_fp16 and args.loss_scaling > 1.0:
             total_loss = total_loss * args.loss_scaling
-        total_loss.persistable = True
 
         return pyreader, total_loss, num_seqs
     else:
@@ -282,7 +278,7 @@ def train(args):
                     use_fp16=args.use_fp16,
                     loss_scaling=args.loss_scaling)
 
-                fluid.memory_optimize(train_program)
+                fluid.memory_optimize(train_program, skip_opt_set=[loss.name, num_seqs.name])
 
         if args.verbose:
             if args.in_tokens:
@@ -304,7 +300,7 @@ def train(args):
                     bert_config=bert_config,
                     is_training=False)
 
-                fluid.memory_optimize(test_prog)
+                fluid.memory_optimize(test_prog, skip_opt_set=[unique_ids.name, start_logits.name, end_logits.name, num_seqs.name])
 
         test_prog = test_prog.clone(for_test=True)