exclude null block

Signed-off-by: Chen Zhang <[email protected]>

Author: heheda12345

vllm/v1/core/block_pool.py

@@ -251,7 +251,7 @@ def reset_prefix_cache(self) -> bool:
         if num_used_blocks != 1:  # The null block is always marked as used
             logger.warning(
                 "Failed to reset prefix cache because some "
-                "blocks (%d) are not freed yet", num_used_blocks)
+                "blocks (%d) are not freed yet", num_used_blocks - 1)
             return False
 
         # Remove all hashes so that no new blocks will hit.