Cleanup unused resources after DeepEP operation (sgl-project#4996)

Author: fzyzcjy

python/sglang/srt/layers/moe/ep_moe/token_dispatcher.py

@@ -184,11 +184,6 @@ def dispatch_b(
                 (num_experts + 1,), device=hidden_states.device, dtype=torch.int64
             )
 
-        # TODO
-        # masked_m = torch.empty(
-        #     (self.num_local_experts,), device=hidden_states.device, dtype=torch.int64
-        # )
-        # expected_m = 0
         masked_m = expected_m = None
 
         return (
@@ -327,6 +322,8 @@ def combine_a(
     def combine_b(self, output, previous_event):
         hidden_states, event = self._combine_core(output, previous_event)
         event.current_stream_wait() if self.async_finish else ()
+        self.handle = None
+        self.src2dst = None
         return hidden_states
 
     def _combine_core(self, x: torch.Tensor, previous_event):
@@ -402,13 +399,6 @@ def dispatch_b(
     ):
         hook() if self.return_recv_hook else event.current_stream_wait()
 
-        # TODO
-        # reorder_topk_ids = torch.empty(
-        #     (0,), device=hidden_states.device, dtype=torch.int64
-        # )
-        # seg_indptr = torch.zeros(
-        #     (num_experts + 1,), device=hidden_states.device, dtype=torch.int64
-        # )
         reorder_topk_ids = seg_indptr = None
 
         return (
@@ -508,6 +498,7 @@ def _combine_core(
                 return_recv_hook=self.return_recv_hook,
             )
         )
+        self.handle = None
         return combined_hidden_states, event, hook