From 71baf85ae11be24d4ea32d30cb5b8dfb0912a6cc Mon Sep 17 00:00:00 2001
From: Ning Xie <andy.xning@gmail.com>
Date: Sat, 21 Jun 2025 02:18:11 +0800
Subject: [PATCH] [Kernel] mark TorchSDPABackend swap_blocks
 NotImplementedError (#19749)

---
 vllm/attention/backends/torch_sdpa.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/vllm/attention/backends/torch_sdpa.py b/vllm/attention/backends/torch_sdpa.py
index 3e1336a5a..af5fe81dc 100644
--- a/vllm/attention/backends/torch_sdpa.py
+++ b/vllm/attention/backends/torch_sdpa.py
@@ -65,7 +65,7 @@ class TorchSDPABackend(AttentionBackend):
         dst_kv_cache: torch.Tensor,
         src_to_dst: torch.Tensor,
     ) -> None:
-        PagedAttention.swap_blocks(src_kv_cache, dst_kv_cache, src_to_dst)
+        raise NotImplementedError("Swap is not supported in TorchSDPABackend.")
 
     @staticmethod
     def copy_blocks(