Make shared decorated readers' creater be only in main_program

paddle/fluid/operators/reader/create_double_buffer_reader_op.cc

@@ -109,7 +109,9 @@ class CreateDoubleBufferReaderOp : public framework::OperatorBase {
 
     auto place_str = Attr<std::string>("place");
     platform::Place place;
-    if (place_str == "CPU") {
+    if (place_str == "AUTO") {
+      place = dev_place;
+    } else if (place_str == "CPU") {
       place = platform::CPUPlace();
     } else {
       std::istringstream sin(place_str);
@@ -140,8 +142,9 @@ class CreateDoubleBufferReaderOpMaker : public DecoratedReaderMakerBase {
       enum_range.insert(string::Sprintf("CUDA:%d", i));
     }
     enum_range.insert("CPU");
-    AddAttr<std::string>("place", "The double buffer place, default is CPU")
-        .SetDefault("CPU")
+    enum_range.insert("AUTO");
+    AddAttr<std::string>("place", "The double buffer place")
+        .SetDefault("AUTO")
         .InEnum({enum_range});
   }
 };

python/paddle/fluid/layers/io.py

@@ -440,7 +440,7 @@ def open_files(filenames,
     return monkey_patch_reader_methods(main_prog_reader)
 
 
-def __create_decorated_reader__(op_type, reader, attrs={}):
+def __create_unshared_decorated_reader__(op_type, reader, attrs={}):
     var_name = unique_name(op_type)
     startup_blk = default_startup_program().current_block()
     startup_var = startup_blk.create_var(name=var_name)
@@ -456,26 +456,40 @@ def __create_decorated_reader__(op_type, reader, attrs={}):
     return monkey_patch_reader_methods(main_prog_var)
 
 
+def __create_shared_decorated_reader__(op_type, reader, attrs={}):
+    new_reader_name = unique_name(op_type)
+    main_blk = default_main_program().current_block()
+    new_reader = main_blk.create_var(name=new_reader_name)
+    main_blk.append_op(
+        type=op_type,
+        inputs={'UnderlyingReader': reader},
+        outputs={'Out': [new_reader]},
+        attrs=attrs)
+    new_reader.persistable = True
+    new_reader.stop_gradient = True
+    return monkey_patch_reader_methods(new_reader)
+
+
 def shuffle(reader, buffer_size):
-    return __create_decorated_reader__('create_shuffle_reader', reader,
-                                       {'buffer_size': int(buffer_size)})
+    return __create_unshared_decorated_reader__(
+        'create_shuffle_reader', reader, {'buffer_size': int(buffer_size)})
 
 
 def double_buffer(reader, place=None):
     attrs = dict()
     if place is not None:
         attrs['place'] = str(place).upper()
-    return __create_decorated_reader__('create_double_buffer_reader', reader,
-                                       attrs)
+    return __create_unshared_decorated_reader__('create_double_buffer_reader',
+                                                reader, attrs)
 
 
 def multi_pass(reader, pass_num):
-    return __create_decorated_reader__('create_multi_pass_reader', reader,
-                                       {'pass_num': int(pass_num)})
+    return __create_shared_decorated_reader__(
+        'create_multi_pass_reader', reader, {'pass_num': int(pass_num)})
 
 
 def for_parallel(reader):
-    return __create_decorated_reader__('create_threaded_reader', reader)
+    return __create_shared_decorated_reader__('create_threaded_reader', reader)
 
 
 def read_file(file_obj):