Sync from v0.13

vllm/v1/kv_offload/spec.py

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+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+from abc import ABC, abstractmethod
+from collections.abc import Iterator
+from typing import TYPE_CHECKING
+
+import torch
+
+from vllm.attention.backends.abstract import AttentionBackend
+from vllm.logger import init_logger
+from vllm.v1.kv_offload.abstract import LoadStoreSpec, OffloadingManager
+from vllm.v1.kv_offload.worker.worker import OffloadingHandler
+
+if TYPE_CHECKING:
+    from vllm.config import VllmConfig
+
+logger = init_logger(__name__)
+
+
+class OffloadingSpec(ABC):
+    """Spec for an offloading connector"""
+
+    def __init__(self, vllm_config: "VllmConfig"):
+        logger.warning(
+            "Initializing OffloadingSpec. This API is experimental and "
+            "subject to change in the future as we iterate the design."
+        )
+        self.vllm_config = vllm_config
+
+        kv_transfer_config = vllm_config.kv_transfer_config
+        assert kv_transfer_config is not None
+        self.extra_config = kv_transfer_config.kv_connector_extra_config
+
+        self.gpu_block_size = vllm_config.cache_config.block_size
+        self.offloaded_block_size = int(
+            self.extra_config.get("block_size", self.gpu_block_size)
+        )
+
+        assert self.offloaded_block_size % self.gpu_block_size == 0
+
+    @abstractmethod
+    def get_manager(self) -> OffloadingManager:
+        """
+        Get an OffloadingManager that will be used
+        by the scheduler-side offloading connector to track
+        offloaded blocks and manage evictions.
+        """
+        pass
+
+    @abstractmethod
+    def get_handlers(
+        self,
+        kv_caches: dict[str, torch.Tensor],
+        attn_backends: dict[str, type[AttentionBackend]],
+    ) -> Iterator[tuple[type[LoadStoreSpec], type[LoadStoreSpec], OffloadingHandler]]:
+        """
+        Get offloading handlers along with their respective src and dst types.
+
+        Args:
+            kv_caches: A dictionary of layer_name -> gpu_kv_cache tensor.
+            attn_backends: A dictionary of layer_name -> AttentionBackend.
+
+        Yields:
+            Tuples of (src_type, dst_type, offloading_handler).
+        """
+        pass