[Dy2St]Fix abnormal growth of memory in train mode and no_grad for Dy2St (#47398)

Fix abnormal growth of memory in train mode and no_grad for Dy2St

paddle/fluid/eager/to_static/run_program_op_node.h

@@ -403,7 +403,7 @@ inline void RunProgramAPI(
       VLOG(3) << paddle::framework::GenScopeTreeDebugInfo(
           out_scope_vec->front());
 
-      if (is_test) {
+      if (is_test || !egr::Controller::Instance().HasGrad()) {
         VLOG(4) << "is test, set this scope can reused";
         global_inner_scope->SetCanReuesd(true);
         details::GcScope(global_inner_scope);
@@ -481,7 +481,7 @@ inline void RunProgramAPI(
     // Debug info: scope info when run end
     VLOG(3) << paddle::framework::GenScopeTreeDebugInfo(out_scope_vec->front());
     // Step 5. Drop all children scopes while testing.
-    if (is_test) {
+    if (is_test || !egr::Controller::Instance().HasGrad()) {
       out_scope_vec->front()->DropKids();
     }
     VLOG(2) << "The number of sub scopes after forward: "

python/paddle/fluid/dygraph/io.py

@@ -1058,8 +1058,6 @@ def _run_dygraph(instance, input, program_holder):
             continue
         persistable_var._set_grad_type(grad_var.type())
 
-    drop_scope_if_no_grad(instance, tmp_scope_vec)
-
     # 3. prepare output, keep same form with inputs
     outs = output_vars
     if len(output_vars) == 1:
@@ -1067,17 +1065,6 @@ def _run_dygraph(instance, input, program_holder):
     return outs
 
 
-def drop_scope_if_no_grad(instance, scope_vec):
-    tracer = framework._dygraph_tracer()
-    scope = (
-        scope_vec.value().get_scope()
-        if isinstance(scope_vec, (core.VarBase))
-        else scope_vec[0]
-    )
-    if (not instance._is_test) and (not tracer._has_grad):
-        scope.drop_kids()
-
-
 def _run_static_graph(input, program_holder, trace_program):
     main_program = framework.default_main_program()
     param_var_names = _get_persistable_var_names(trace_program)