HiCache, fixing hash value indexing (sgl-project#8636)

Author: xiezhq-hermann

python/sglang/srt/mem_cache/hiradix_cache.py

@@ -436,7 +436,7 @@ def check_prefetch_progress(self, req_id: str):
             last_host_node,
             fetched_token_ids,
             written_indices,
-            hash_value[:min_completed_tokens],
+            hash_value[: min_completed_tokens // self.page_size],
         )
         if len(written_indices):
             self.cache_controller.mem_pool_host.update_prefetch(written_indices)
@@ -529,7 +529,7 @@ def _insert_helper_host(self, node: TreeNode, key: List, host_value, hash_value)
             prefix_len = self.key_match_fn(node.key, key)
             key = key[prefix_len:]
             host_value = host_value[prefix_len:]
-            hash_value = hash_value[prefix_len:]
+            hash_value = hash_value[prefix_len // self.page_size :]
             matched_length += prefix_len
 
             if prefix_len < len(node.key):