Revert "Try to remove wrong logic about max total token in spec decoding" (#14259)

python/sglang/srt/model_executor/model_runner.py

@@ -1697,8 +1697,25 @@ class ModelRunner:
 
         if self.spec_algorithm.is_eagle() or self.spec_algorithm.is_standalone():
             if self.is_draft_worker:
+                self.max_total_num_tokens = self.server_args.draft_runner_cache_size
                 max_num_reqs = self.server_args.max_num_reqs
             else:
+                # We are sharing the `token_to_kv_pool`, and both verify and draft tokens
+                # can be concurrently allocated, so we should give a headroom for it.
+                self.server_args.draft_runner_cache_size = (
+                    self.max_total_num_tokens
+                    # draft
+                    + max_num_reqs
+                    * self.server_args.speculative_num_steps
+                    * self.server_args.speculative_eagle_topk
+                    # verify
+                    + max_num_reqs * self.server_args.speculative_num_draft_tokens
+                    # buffer
+                    + 100
+                )
+                # Target worker and draft worker shares the same indices for the
+                # token_to_kv_pool, so we should make sure to match max_total_num_tokens.
+                self.max_total_num_tokens = self.server_args.draft_runner_cache_size
                 self.server_args.max_num_reqs = max_num_reqs
 
         if max_total_tokens is not None: