[V1] Add BlockTable class (#11693)

Signed-off-by: Woosuk Kwon <woosuk.kwon@berkeley.edu>

vllm/v1/worker/block_table.py

@@ -0,0 +1,78 @@
+from typing import List
+
+import numpy as np
+import torch
+
+from vllm.logger import init_logger
+
+logger = init_logger(__name__)
+
+
+class BlockTable:
+
+    def __init__(
+        self,
+        max_num_reqs: int,
+        max_model_len: int,
+        max_num_blocks_per_req: int,
+        pin_memory: bool,
+        device: torch.device,
+    ):
+        self.max_num_reqs = max_num_reqs
+        self.max_model_len = max_model_len
+        self.max_num_blocks_per_req = max_num_blocks_per_req
+        self.pin_memory = pin_memory
+        self.device = device
+
+        self.block_table = torch.zeros(
+            (max_num_reqs, max_num_blocks_per_req),
+            device=self.device,
+            dtype=torch.int32,
+        )
+        self.block_table_cpu = torch.zeros(
+            (max_num_reqs, max_num_blocks_per_req),
+            device="cpu",
+            dtype=torch.int32,
+            pin_memory=pin_memory,
+        )
+        self.block_table_np = self.block_table_cpu.numpy()
+        self.num_blocks_per_row = np.zeros(max_num_reqs, dtype=np.int32)
+
+    def append_row(
+        self,
+        row_idx: int,
+        start: int,
+        block_ids: List[int],
+    ) -> None:
+        num_blocks = len(block_ids)
+        self.block_table_np[row_idx, start:start + num_blocks] = block_ids
+        self.num_blocks_per_row[row_idx] = start + num_blocks
+
+    def add_row(self, row_idx: int, block_ids: List[int]) -> None:
+        self.append_row(row_idx, 0, block_ids)
+
+    def move_row(self, src: int, tgt: int) -> None:
+        num_blocks = self.num_blocks_per_row[src]
+        self.block_table_np[tgt, :num_blocks] = self.block_table_np[
+            src, :num_blocks]
+        self.num_blocks_per_row[tgt] = num_blocks
+
+    def commit(self, num_reqs: int) -> None:
+        self.block_table[:num_reqs].copy_(self.block_table_cpu[:num_reqs],
+                                          non_blocking=True)
+
+    def clear(self) -> None:
+        self.block_table.fill_(0)
+        self.block_table_cpu.fill_(0)
+
+    def get_device_tensor(self) -> torch.Tensor:
+        """Ruturns the device tensor of the block table."""
+        return self.block_table
+
+    def get_cpu_tensor(self) -> torch.Tensor:
+        """Returns the CPU tensor of the block table."""
+        return self.block_table_cpu
+
+    def get_numpy_array(self) -> np.ndarray:
+        """Returns the numpy array of the block table."""
+        return self.block_table_np