diff --git a/mmdet/core/__init__.py b/mmdet/core/__init__.py
index 81ee7311bcd5e7c534e55902ddc799a4e83225b3..20e124bd21f6c99e660a08e6821cfcdbc7dcfb5a 100644
--- a/mmdet/core/__init__.py
+++ b/mmdet/core/__init__.py
@@ -1,4 +1,4 @@
-from .rpn_ops import *  # noqa: F401, F403
+from .anchor import *  # noqa: F401, F403
 from .bbox_ops import *  # noqa: F401, F403
 from .mask_ops import *  # noqa: F401, F403
 from .losses import *  # noqa: F401, F403
diff --git a/mmdet/core/rpn_ops/__init__.py b/mmdet/core/anchor/__init__.py
similarity index 100%
rename from mmdet/core/rpn_ops/__init__.py
rename to mmdet/core/anchor/__init__.py
diff --git a/mmdet/core/rpn_ops/anchor_generator.py b/mmdet/core/anchor/anchor_generator.py
similarity index 100%
rename from mmdet/core/rpn_ops/anchor_generator.py
rename to mmdet/core/anchor/anchor_generator.py
diff --git a/mmdet/core/rpn_ops/anchor_target.py b/mmdet/core/anchor/anchor_target.py
similarity index 100%
rename from mmdet/core/rpn_ops/anchor_target.py
rename to mmdet/core/anchor/anchor_target.py
diff --git a/mmdet/core/utils/__init__.py b/mmdet/core/utils/__init__.py
index e04da6a9a5c82c02c924ecd7c763aaf8b1c02d4e..9e67c7f47c9d56aa5804716da99506254ce3ae76 100644
--- a/mmdet/core/utils/__init__.py
+++ b/mmdet/core/utils/__init__.py
@@ -1,9 +1,8 @@
 from .dist_utils import (init_dist, reduce_grads, DistOptimizerHook,
                          DistSamplerSeedHook)
-from .hooks import EmptyCacheHook
 from .misc import tensor2imgs, unmap, multi_apply
 
 __all__ = [
     'init_dist', 'reduce_grads', 'DistOptimizerHook', 'DistSamplerSeedHook',
-    'EmptyCacheHook', 'tensor2imgs', 'unmap', 'multi_apply'
+    'tensor2imgs', 'unmap', 'multi_apply'
 ]
diff --git a/mmdet/core/utils/hooks.py b/mmdet/core/utils/hooks.py
deleted file mode 100644
index 7186ad75ccce950c13ae65e6c94dfea106e6cd03..0000000000000000000000000000000000000000
--- a/mmdet/core/utils/hooks.py
+++ /dev/null
@@ -1,11 +0,0 @@
-import torch
-from mmcv.runner import Hook
-
-
-class EmptyCacheHook(Hook):
-
-    def before_epoch(self, runner):
-        torch.cuda.empty_cache()
-
-    def after_epoch(self, runner):
-        torch.cuda.empty_cache()