[polish] add update directory in gemini; rename AgChunk to ChunkV2 (#1432)

colossalai/gemini/update/__init__.py

+from .chunkv2 import ChunkV2

colossalai/gemini/ag_chunk.py → colossalai/gemini/update/chunkv2.py

@@ -8,7 +8,7 @@ from colossalai.gemini.chunk import TensorState, STATE_TRANS, TensorInfo, ChunkF
     free_storage, alloc_storage
 
 
-class AgChunk:
+class ChunkV2:
     def __init__(self,
                  chunk_size: int,
                  process_group: ColoProcessGroup,

tests/test_gemini/chunk/test_agchunk.py → tests/test_gemini/update/test_chunkv2.py

@@ -9,7 +9,7 @@ from colossalai.utils import free_port, get_current_device
 from colossalai.tensor import ProcessGroup as ColoProcessGroup
 from colossalai.tensor import ColoParameter
 from colossalai.gemini import TensorState
-from colossalai.gemini.ag_chunk import AgChunk
+from colossalai.gemini.update import ChunkV2
 
 
 def dist_sum(x):
@@ -38,7 +38,7 @@ def check_euqal(param, param_cp):
 def exam_chunk_basic(init_device, keep_gathered, pin_memory):
     world_size = torch.distributed.get_world_size()
     pg = ColoProcessGroup()
-    my_chunk = AgChunk(
+    my_chunk = ChunkV2(
         chunk_size=1024,
         process_group=pg,
         dtype=torch.float32,