[model] fix kv cache (#7564)

src/llamafactory/model/model_utils/kv_cache.py

@@ -0,0 +1,44 @@
+# Copyright 2025 the LlamaFactory team.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from typing import TYPE_CHECKING
+
+from ...extras import logging
+
+
+logger = logging.get_logger(__name__)
+
+
+if TYPE_CHECKING:
+    from transformers import PretrainedConfig
+
+    from ...hparams import ModelArguments
+
+
+def configure_kv_cache(config: "PretrainedConfig", model_args: "ModelArguments", is_trainable: bool) -> None:
+    if not is_trainable:
+        setattr(config, "use_cache", model_args.use_cache)
+        if hasattr(config, "text_config"):
+            setattr(config.text_config, "use_cache", model_args.use_cache)
+
+        if model_args.use_cache:
+            logger.info_rank0("KV cache is enabled for faster generation.")
+        else:
+            logger.info_rank0("KV cache is disabled.")
+    else:
+        setattr(config, "use_cache", False)
+        if hasattr(config, "text_config"):
+            setattr(config.text_config, "use_cache", False)
+
+        logger.info_rank0("KV cache is disabled during training.")