[v1] Move block pool operations to a separate class (#13973)

Signed-off-by: Chen Zhang <zhangch99@outlook.com>
Co-authored-by: Cody Yu <hao.yu.cody@gmail.com>

tests/v1/core/test_prefix_caching.py

@@ -1,12 +1,16 @@
 # SPDX-License-Identifier: Apache-2.0
 """Compare the with and without prefix caching."""
+from typing import List
+
 import pytest
 
 from vllm.multimodal.inputs import MultiModalKwargs, PlaceholderRange
 from vllm.sampling_params import SamplingParams
 from vllm.utils import cdiv
+from vllm.v1.core.block_pool import BlockPool
 from vllm.v1.core.kv_cache_manager import KVCacheManager, Request
-from vllm.v1.core.kv_cache_utils import KVCacheBlock, hash_block_tokens
+from vllm.v1.core.kv_cache_utils import (BlockHashType, KVCacheBlock,
+                                         hash_block_tokens)
 
 
 def make_request(request_id,
@@ -62,14 +66,14 @@ def test_prefill():
     for block_id in (0, 1, 2):
         block_tokens = tuple(all_token_ids[block_id * 16:(block_id + 1) * 16])
         block_hash = hash_block_tokens(parent_block_hash, block_tokens)
-        assert manager.block_pool[block_id].block_hash == block_hash
-        assert manager.block_pool[block_id].ref_cnt == 1
+        assert manager.block_pool.blocks[block_id].block_hash == block_hash
+        assert manager.block_pool.blocks[block_id].ref_cnt == 1
         parent_block_hash = block_hash.hash_value
 
     # Check partial/preallocated block metadata
     for block_id in (3, 4):
-        assert manager.block_pool[block_id].block_hash is None
-        assert manager.block_pool[block_id].ref_cnt == 1
+        assert manager.block_pool.blocks[block_id].block_hash is None
+        assert manager.block_pool.blocks[block_id].ref_cnt == 1
 
     # Cache hit in the common prefix when the original block is still in use.
     # Incomplete 1 block (5 tokens)
@@ -86,20 +90,21 @@ def test_prefill():
         assert block.ref_cnt == 2
 
     # At this point, we should have 3 free blocks left.
-    assert manager.free_block_queue.num_free_blocks == 3
+    assert manager.block_pool.free_block_queue.num_free_blocks == 3
 
     manager.free(req0)
     manager.free(req1)
 
     # All blocks should be available.
-    assert manager.free_block_queue.num_free_blocks == 10
+    assert manager.block_pool.free_block_queue.num_free_blocks == 10
     # The order should be
     # [unallocated (7, 8, 9)]
     # [unique_req0 (4, 3)]
     # [unique_req1 (6, 5)]
     # [common (2, 1, 0)]
     assert [
-        b.block_id for b in manager.free_block_queue.get_all_free_blocks()
+        b.block_id
+        for b in manager.block_pool.free_block_queue.get_all_free_blocks()
     ] == [7, 8, 9, 4, 3, 6, 5, 2, 1, 0]
 
     # Cache hit in the common prefix when the original block is already free.
@@ -116,12 +121,14 @@ def test_prefill():
 
     # Although we only have 5 free blocks, we have 8 blocks in
     # the free block queue due to lazy removal.
-    assert manager.free_block_queue.num_free_blocks == 5
+    assert manager.block_pool.free_block_queue.num_free_blocks == 5
     assert all([
-        b.ref_cnt == 0 for b in manager.free_block_queue.get_all_free_blocks()
+        b.ref_cnt == 0
+        for b in manager.block_pool.free_block_queue.get_all_free_blocks()
     ])
-    assert len([b
-                for b in manager.free_block_queue.get_all_free_blocks()]) == 5
+    assert len([
+        b for b in manager.block_pool.free_block_queue.get_all_free_blocks()
+    ]) == 5
 
     manager.free(req2)
 
@@ -133,9 +140,9 @@ def test_prefill():
     blocks = manager.allocate_slots(req3, 16 * 9, computed_blocks)
     # This block ID order also checks the eviction order.
     assert [b.block_id for b in blocks] == [9, 4, 3, 6, 5, 8, 7, 2, 1, 0]
-    assert manager.free_block_queue.num_free_blocks == 0
-    assert manager.free_block_queue.free_list_head is None
-    assert manager.free_block_queue.free_list_tail is None
+    assert manager.block_pool.free_block_queue.num_free_blocks == 0
+    assert manager.block_pool.free_block_queue.free_list_head is None
+    assert manager.block_pool.free_block_queue.free_list_tail is None
 
 
 def test_decode():
@@ -219,13 +226,14 @@ def test_evict():
     assert len(blocks) == 3  # 3 full blocks
     last_token_id += 3 * 16
 
-    assert manager.free_block_queue.num_free_blocks == 0
+    assert manager.block_pool.free_block_queue.num_free_blocks == 0
 
     manager.free(req0)
     manager.free(req1)
-    assert manager.free_block_queue.num_free_blocks == 10
+    assert manager.block_pool.free_block_queue.num_free_blocks == 10
     assert [
-        b.block_id for b in manager.free_block_queue.get_all_free_blocks()
+        b.block_id
+        for b in manager.block_pool.free_block_queue.get_all_free_blocks()
     ] == [6, 5, 4, 3, 2, 1, 0, 9, 8, 7]
 
     # Touch the first 2 blocks.
@@ -235,7 +243,7 @@ def test_evict():
     assert num_computed_tokens == 2 * 16
     blocks = manager.allocate_slots(req2, 3, computed_blocks)
     assert [b.block_id for b in blocks] == [6, 5]
-    assert manager.free_block_queue.num_free_blocks == 6
+    assert manager.block_pool.free_block_queue.num_free_blocks == 6
 
 
 def test_hash_block_correct_reuse():
@@ -274,7 +282,7 @@ def test_hash_block_correct_reuse():
     blocks = manager.allocate_slots(req, num_tokens - 1, computed_blocks)
     assert len(blocks) == 1
 
-    assert manager.block_pool[blocks[0].block_id].block_hash is None
+    assert manager.block_pool.blocks[blocks[0].block_id].block_hash is None
 
 
 def test_computed_blocks_not_evicted():
@@ -413,13 +421,9 @@ def test_cache_blocks():
     function of KVCacheManager.
     """
     block_size = 4
-    manager = KVCacheManager(
-        block_size=block_size,
+    block_pool = BlockPool(
         num_gpu_blocks=5,
-        max_model_len=8192,
-        sliding_window=None,
         enable_caching=True,
-        num_preallocate_tokens=0,
     )
     # Req:
     #  Block 0: [0, 1, 2, 3]
@@ -430,26 +434,31 @@ def test_cache_blocks():
 
     # Test that blocks are cached correctly for 2 full blocks from the start.
     blocks = [KVCacheBlock(block_id=i) for i in range(2)]
+    block_hashes: List[BlockHashType] = []
 
-    manager._cache_full_blocks(
+    block_pool.cache_full_blocks(
         request=req,
-        blk_start_idx=0,
-        full_blocks=blocks,
-        prev_block=None,
+        blocks=blocks,
+        block_hashes=block_hashes,
+        num_cached_blocks=0,
+        num_full_blocks=2,
+        block_size=block_size,
     )
 
-    assert len(manager.cached_block_hash_to_block) == 2
+    assert len(block_pool.cached_block_hash_to_block) == 2
     assert all([block.block_hash is not None for block in blocks])
 
     # Test that blocks that don't start from the beginning are cached correctly.
-    blocks = [KVCacheBlock(block_id=2)]
-    manager._cache_full_blocks(
+    blocks += [KVCacheBlock(block_id=2)]
+    block_pool.cache_full_blocks(
         request=req,
-        blk_start_idx=2,
-        full_blocks=blocks,
-        prev_block=None,
+        blocks=blocks,
+        block_hashes=block_hashes,
+        num_cached_blocks=2,
+        num_full_blocks=3,
+        block_size=block_size,
     )
-    assert len(manager.cached_block_hash_to_block) == 3
+    assert len(block_pool.cached_block_hash_to_block) == 3
     assert blocks[0].block_hash is not None
 
 
@@ -580,7 +589,7 @@ def test_prefill_not_enough_free_blocks_with_computed_blocks():
     # Req3 is Req2 + 3 new blocks, so the first 6 blocks are computed,
     # but it cannot be allocated due to insufficient free blocks (2).
     # In this case, the ref_cnt of the computed blocks should not be changed.
-    assert manager.free_block_queue.num_free_blocks == 5
+    assert manager.block_pool.free_block_queue.num_free_blocks == 5
     req3 = make_request("3", common_token_ids * 3)
     computed_blocks, num_computed_tokens = manager.get_computed_blocks(req3)
     assert computed_blocks == block_part1
@@ -621,12 +630,12 @@ def test_reset_prefix_cache():
 
     # Failed to reset prefix cache because some blocks are not freed yet.
     assert not manager.reset_prefix_cache()
-    assert manager.cached_block_hash_to_block
+    assert manager.block_pool.cached_block_hash_to_block
 
     # Free the blocks.
     manager.free(req0)
     manager.free(req1)
 
     assert manager.reset_prefix_cache()
-    assert not manager.cached_block_hash_to_block
-    assert all([blk.block_hash is None for blk in manager.block_pool])
+    assert not manager.block_pool.cached_block_hash_to_block
+    assert all([blk.block_hash is None for blk in manager.block_pool.blocks])