Refactor Req.fill_ids into full_untruncated_fill_ids + fill_len with equivalence (#26637)

python/sglang/bench_one_batch.py

@@ -371,9 +371,10 @@ def prepare_inputs_for_correctness_test(bench_args, tokenizer, custom_prompts):
             origin_input_ids=array("q", tmp_input_ids),
             sampling_params=sampling_params,
         )
-        req.fill_ids = req.origin_input_ids
+        req.full_untruncated_fill_ids = req.origin_input_ids
+        req.fill_len = len(req.full_untruncated_fill_ids)
         req.logprob_start_len = -1
-        req.set_extend_input_len(len(req.fill_ids) - len(req.prefix_indices))
+        req.set_extend_input_len(req.fill_len - len(req.prefix_indices))
         reqs.append(req)
 
     return input_ids, reqs
@@ -384,14 +385,15 @@ def prepare_extend_inputs_for_correctness_test(
 ):
     for i in range(len(reqs)):
         req: Req = reqs[i]
-        req.fill_ids.extend(input_ids[i][bench_args.cut_len :])
+        req.full_untruncated_fill_ids += input_ids[i][bench_args.cut_len :]
+        req.fill_len = len(req.full_untruncated_fill_ids)
         if model_runner is not None:
             # Use req.req_pool_idx instead of i to handle slot 0 padding correctly
             req.prefix_indices = model_runner.req_to_token_pool.req_to_token[
                 req.req_pool_idx, : bench_args.cut_len
             ].to(req.prefix_indices.dtype)
             req.logprob_start_len = -1
-            req.set_extend_input_len(len(req.fill_ids) - len(req.prefix_indices))
+            req.set_extend_input_len(req.fill_len - len(req.prefix_indices))
     return reqs
 
 
@@ -416,9 +418,10 @@ def prepare_synthetic_inputs_for_latency_test(
             origin_input_ids=array("q", input_ids[i]),
             sampling_params=sampling_params,
         )
-        req.fill_ids = req.origin_input_ids
+        req.full_untruncated_fill_ids = req.origin_input_ids
+        req.fill_len = len(req.full_untruncated_fill_ids)
         req.logprob_start_len = -1
-        req.set_extend_input_len(len(req.fill_ids) - len(req.prefix_indices))
+        req.set_extend_input_len(req.fill_len - len(req.prefix_indices))
         reqs.append(req)
 
     return reqs
@@ -557,7 +560,7 @@ class _MlxBenchRunner:
         req_ids = [str(req.rid) for req in reqs]
         results = []
         for rid, req in zip(req_ids, reqs):
-            token_ids = [int(t) for t in req.fill_ids]
+            token_ids = [int(t) for t in req.get_fill_ids()]
             next_token = self.mlx_runner.prefill(
                 req_id=rid,
                 new_token_ids=token_ids,

python/sglang/srt/disaggregation/decode.py

@@ -1048,9 +1048,7 @@ class DecodePreallocQueue(DecodeHiCachePreallocMixin):
 
     @property
     def num_tokens_pre_allocated(self):
-        return sum(
+        return sum(decode_req.req.fill_len for decode_req in self.transfer_queue.queue)
-            len(decode_req.req.fill_ids) for decode_req in self.transfer_queue.queue
-        )
 
     def _need_space_for_single_req(
         self, retractable_tokens: Optional[int] = None
@@ -1380,10 +1378,11 @@ class DecodePreallocQueue(DecodeHiCachePreallocMixin):
             kv_loc,
         )
 
-        # Truncate fill_ids to kv_committed_len so cache_unfinished_req only
+        # Truncate fill_len to kv_committed_len so cache_unfinished_req only
         # inserts committed KV into the radix tree. The last output token
-        # hasn't had KV committed yet (fill_ids is 1 ahead).
+        # hasn't had KV committed yet (output_ids is 1 ahead).
-        req.fill_ids = (req.origin_input_ids + req.output_ids)[: req.kv_committed_len]
+        req.full_untruncated_fill_ids = req.origin_input_ids + req.output_ids
+        req.fill_len = req.kv_committed_len
         # Set prefix_indices so downstream consumers (init_next_round_input,
         # prepare_for_extend) see the correct prefix length. In the agg path
         # this is done inside init_next_round_input, but decode-disagg needs
@@ -1391,7 +1390,7 @@ class DecodePreallocQueue(DecodeHiCachePreallocMixin):
         req.prefix_indices = (
             prefix_indices if prefix_len > 0 else torch.empty((0,), dtype=torch.int64)
         )
-        req.set_extend_input_len(len(req.fill_ids) - total_prefix_len)
+        req.set_extend_input_len(req.fill_len - total_prefix_len)
 
         # Return the transfer destination indices:
         if self.scheduler.enable_hisparse:
@@ -1839,13 +1838,12 @@ class SchedulerDisaggregationDecodeMixin:
                 else:
                     tree_cache = self.tree_cache
                 req.init_next_round_input(tree_cache)
-                # Truncate fill_ids to kv_committed_len so cache_unfinished_req
+                # Truncate fill_len to kv_committed_len so cache_unfinished_req
-                # only sees committed KV (fill_ids includes one uncommitted token).
+                # only sees committed KV (full array includes one uncommitted
+                # token because init_next_round_input rebuilt it as full).
                 if req.kv_committed_len is not None:
-                    req.fill_ids = req.fill_ids[: req.kv_committed_len]
+                    req.fill_len = req.kv_committed_len
-                    req.set_extend_input_len(
+                    req.set_extend_input_len(req.fill_len - len(req.prefix_indices))
-                        len(req.fill_ids) - len(req.prefix_indices)
-                    )
             else:
                 waiting_queue.append(req)
 

python/sglang/srt/disaggregation/decode_schedule_batch_mixin.py

@@ -29,7 +29,7 @@ class ScheduleBatchDisaggregationDecodeMixin:
 
         self.forward_mode = ForwardMode.PREBUILT
         reqs = self.reqs
-        input_ids = [r.fill_ids[len(r.prefix_indices) :] for r in reqs]
+        input_ids = [r.get_fill_ids()[len(r.prefix_indices) :] for r in reqs]
         extend_num_tokens = sum(len(ids) for ids in input_ids)
         seq_lens = []
         pre_lens = []

python/sglang/srt/disaggregation/prefill.py

@@ -870,7 +870,7 @@ class SchedulerDisaggregationPrefillMixin:
             elif self.enable_overlap:
                 # Delay KV transfer to process_batch_result_disagg_prefill when overlap is enabled to ensure results are resolved
                 self.chunked_req.tmp_end_idx = min(
-                    len(self.chunked_req.fill_ids),
+                    self.chunked_req.fill_len,
                     len(self.chunked_req.origin_input_ids),
                 )
             else:
@@ -906,7 +906,7 @@ class SchedulerDisaggregationPrefillMixin:
         end_idx = (
             end_idx
             if end_idx is not None
-            else min(len(req.fill_ids), len(req.origin_input_ids))
+            else min(req.fill_len, len(req.origin_input_ids))
         )
 
         if not last_chunk:
@@ -937,7 +937,7 @@ class SchedulerDisaggregationPrefillMixin:
             # length here avoids emitting an extra state page when the sampled
             # token crosses a page boundary, which mismatched src/dst lengths in
             # group_concurrent_contiguous.
-            seq_len = min(len(req.fill_ids), len(req.origin_input_ids))
+            seq_len = min(req.fill_len, len(req.origin_input_ids))
 
             def _mamba_payload():
                 return [

python/sglang/srt/dllm/mixin/req.py

@@ -42,11 +42,11 @@ class ReqDllmMixin:
         prefix_length = len(self.prefix_indices)
         min_required_length = prefix_length + self.dllm_config.block_size
 
-        if len(self.fill_ids) < min_required_length:
+        if self.fill_len < min_required_length:
             # still incoming stage
             return
 
-        input_block = self.fill_ids[prefix_length:min_required_length]
+        input_block = self.get_fill_ids()[prefix_length:min_required_length]
         is_prefill_phase = self.dllm_config.mask_id not in input_block
 
         if is_prefill_phase:
@@ -57,14 +57,15 @@ class ReqDllmMixin:
     def _init_fill_ids_for_dllm(self: Req):
         self.dllm_block_offset = (
             0
-            if not self.fill_ids
+            if self.fill_len == 0
             else self.dllm_block_offset + self.dllm_config.block_size
         )
-        self.fill_ids = (
+        self.full_untruncated_fill_ids = (
             self.origin_input_ids
             + self.output_ids
             + array("q", [self.dllm_config.mask_id] * self.dllm_config.block_size)
         )
+        self.fill_len = len(self.full_untruncated_fill_ids)
 
     def _update_block_offset_for_dllm(self):
         prefix_len = len(self.prefix_indices)

python/sglang/srt/dllm/mixin/scheduler.py

@@ -80,7 +80,9 @@ class SchedulerDllmMixin:
                 if new_tokens == 0:
                     continue
 
-                req.fill_ids[-new_tokens:] = array("q", next_token_ids)
+                req.full_untruncated_fill_ids[
+                    req.fill_len - new_tokens : req.fill_len
+                ] = array("q", next_token_ids)
                 self.metrics_reporter.num_generated_tokens += new_tokens
 
                 req.output_ids.extend(next_token_ids)

python/sglang/srt/hardware_backend/mlx/tp_worker.py

@@ -185,7 +185,7 @@ class MlxTpModelWorker(TpModelWorker):
                 else:
                     # New prefill
                     prefix_slot_ids = req.prefix_indices.tolist()
-                    full_token_ids = list(req.fill_ids)
+                    full_token_ids = list(req.get_fill_ids())
                     next_token = self._mlx_runner.prefill(
                         req_id=req.rid,
                         new_token_ids=req_token_ids,
@@ -330,7 +330,7 @@ class MlxTpModelWorker(TpModelWorker):
             else:
                 # New prefill
                 prefix_slot_ids = req.prefix_indices.tolist()
-                full_token_ids = list(req.fill_ids)
+                full_token_ids = list(req.get_fill_ids())
                 pending_prefills.append(
                     self._mlx_runner.prefill_start(
                         req_id=req.rid,

python/sglang/srt/managers/hisparse_coordinator.py

@@ -207,7 +207,7 @@ class HiSparseCoordinator:
         req.hisparse_staging = True
 
         full_kv_indices = self.req_to_token_pool.req_to_token[
-            req.req_pool_idx, : len(req.fill_ids)
+            req.req_pool_idx, : req.fill_len
         ].to(dtype=torch.int64, copy=True)
         device_indices = (
             self.mem_pool_device.translate_loc_from_full_to_hisparse_device(
@@ -298,7 +298,7 @@ class HiSparseCoordinator:
 
     def alloc_device_buffer(self, req: Req) -> None:
         if self.is_dsv4_hisparse:
-            allocated_len = len(req.fill_ids)
+            allocated_len = req.fill_len
             alloc_size = self.padded_buffer_size
         else:
             allocated_len = req.kv_allocated_len
@@ -707,7 +707,7 @@ class HiSparseCoordinator:
         # Wait for any in-flight staging DMA to complete before freeing
         self.write_staging_stream.synchronize()
 
-        prefill_len = len(req.fill_ids)
+        prefill_len = req.fill_len
         allocated_locs = self.req_to_token_pool.req_to_token[
             req.req_pool_idx, :prefill_len
         ]

python/sglang/srt/managers/schedule_batch.py

@@ -696,8 +696,11 @@ class Req(ReqDllmMixin):
         )  # Before image padding
         # Each decode stage's output ids
         self.output_ids = array("q")
-        # fill_ids = origin_input_ids + output_ids. Updated if chunked.
+        # Full untruncated sequence: origin + output (+ DLLM mask block).
-        self.fill_ids = array("q")
+        # Rebuilt at the top of each init_next_round_input; admission only
+        # updates fill_len, never mutates this array's length.
+        self.full_untruncated_fill_ids = array("q")
+        self.fill_len: int = 0
 
         self.session = session
         self.input_embeds = input_embeds
@@ -959,8 +962,8 @@ class Req(ReqDllmMixin):
         # the start index of the sent kv cache
         # We want to send it chunk by chunk for chunked prefill.
         # After every chunk forward, we do the following:
-        # kv_send(req.input_ids[req.start_send_idx:len(req.fill_ids)])
+        # kv_send(req.input_ids[req.start_send_idx:req.fill_len])
-        # start_send_idx = len(req.fill_ids)
+        # start_send_idx = req.fill_len
         self.start_send_idx: int = 0
 
         # For overlap schedule, we delay the kv transfer until `process_batch_result_disagg_prefill` rather than `process_prefill_chunk` in non-overlap
@@ -1062,6 +1065,9 @@ class Req(ReqDllmMixin):
         # Whether request reached finished condition
         return self.finished_reason is not None
 
+    def get_fill_ids(self) -> array:
+        return self.full_untruncated_fill_ids[: self.fill_len]
+
     def init_next_round_input(
         self,
         tree_cache: Optional[BasePrefixCache] = None,
@@ -1071,9 +1077,10 @@ class Req(ReqDllmMixin):
             self._init_fill_ids_for_dllm()
             self.determine_dllm_phase()
         else:
-            self.fill_ids = self.origin_input_ids + self.output_ids
+            self.full_untruncated_fill_ids = self.origin_input_ids + self.output_ids
+            self.fill_len = len(self.full_untruncated_fill_ids)
 
-        input_len = len(self.fill_ids)
+        input_len = self.fill_len
 
         # Streaming sessions reuse committed KV from the session slot, so
         # custom logprob_start_len is not supported — override to -1.
@@ -1091,7 +1098,9 @@ class Req(ReqDllmMixin):
             )
             self.logprob_start_len = -1
 
-        token_ids_to_match = self.fill_ids[: self._compute_max_prefix_len(input_len)]
+        token_ids_to_match = self.get_fill_ids()[
+            : self._compute_max_prefix_len(input_len)
+        ]
 
         # Disable prefix caching when embed overrides are present: same token IDs
         # with different override vectors must not share cached KV values.
@@ -1154,7 +1163,7 @@ class Req(ReqDllmMixin):
                 )
             )
 
-        self.set_extend_input_len(len(self.fill_ids) - len(self.prefix_indices))
+        self.set_extend_input_len(self.fill_len - len(self.prefix_indices))
 
     def _compute_max_prefix_len(self, input_len: int) -> int:
         # NOTE: the matched length is at most 1 less than the input length to enable logprob computation
@@ -1420,7 +1429,7 @@ class Req(ReqDllmMixin):
         # - extend_input_len: Number of tokens that need to be processed in this extend batch
         self.extend_input_len = extend_input_len
         if self.logprob_start_len == -1:
-            logprob_start_len = len(self.fill_ids)
+            logprob_start_len = self.fill_len
         else:
             # logprob_start_len should be at least the length of the prefix indices
             logprob_start_len = max(self.logprob_start_len, len(self.prefix_indices))
@@ -1544,7 +1553,7 @@ def _compute_chunked_req_next_prompt_token(
 ) -> Optional[int]:
     if chunked_req is None:
         return None
-    fill_len = len(chunked_req.fill_ids)
+    fill_len = chunked_req.fill_len
     if fill_len >= len(chunked_req.origin_input_ids):
         return None
     return int(chunked_req.origin_input_ids[fill_len])
@@ -1892,10 +1901,10 @@ class ScheduleBatch(ScheduleBatchDisaggregationDecodeMixin):
 
         # Init tensors
         reqs = self.reqs
-        input_ids = [r.fill_ids[len(r.prefix_indices) :] for r in reqs]
+        input_ids = [r.get_fill_ids()[len(r.prefix_indices) :] for r in reqs]
         extend_num_tokens = sum(len(ids) for ids in input_ids)
-        seq_lens = [len(r.fill_ids) for r in reqs]
+        seq_lens = [r.fill_len for r in reqs]
-        orig_seq_lens = [max(len(r.fill_ids), len(r.origin_input_ids)) for r in reqs]
+        orig_seq_lens = [max(r.fill_len, len(r.origin_input_ids)) for r in reqs]
         prefix_lens = [len(r.prefix_indices) for r in reqs]
         extend_lens = [r.extend_input_len for r in reqs]
 
@@ -1948,7 +1957,7 @@ class ScheduleBatch(ScheduleBatchDisaggregationDecodeMixin):
             # If input_embeds are available, store them
             if req.input_embeds is not None:
                 # Slice to match extend_input_len — PrefillAdder truncates
-                # fill_ids/extend_input_len on chunk overflow but not input_embeds.
+                # fill_len/extend_input_len on chunk overflow but not input_embeds.
                 input_embeds.extend(
                     req.input_embeds[pre_len : pre_len + req.extend_input_len]
                 )
@@ -2022,16 +2031,16 @@ class ScheduleBatch(ScheduleBatchDisaggregationDecodeMixin):
                 # to compute input logprobs. E.g., (chunk size 2)
                 #
                 # input_logprobs = [1, 2, 3, 4]
-                # fill_ids = [1, 2]
+                # get_fill_ids() = [1, 2]
                 # extend_input_logprob_token_id = [2, 3]
                 #
                 # Note that it can also overflow. In this case, we pad it with 0.
                 # input_logprobs = [1, 2, 3, 4]
-                # fill_ids = [3, 4]
+                # get_fill_ids() = [3, 4]
                 # extend_input_logprob_token_id = [4, 0]
                 global_start_idx, global_end_idx = (
                     len(req.prefix_indices),
-                    len(req.fill_ids),
+                    req.fill_len,
                 )
                 if req.logprob_start_len == -1:
                     logprob_start_len = len(req.origin_input_ids)
@@ -2261,7 +2270,8 @@ class ScheduleBatch(ScheduleBatchDisaggregationDecodeMixin):
         running_bs = running_batch.batch_size()
 
         for req in running_batch.reqs:
-            req.fill_ids = req.origin_input_ids + req.output_ids
+            req.full_untruncated_fill_ids = req.origin_input_ids + req.output_ids
+            req.fill_len = len(req.full_untruncated_fill_ids)
             req.set_extend_input_len(1)
 
         # Decode tokens of the running portion live in future_map.output_tokens_buf.

python/sglang/srt/managers/schedule_policy.py

@@ -660,7 +660,7 @@ class PrefillAdder:
         )
 
         req.extend_input_len = trunc_len
-        req.fill_ids = req.fill_ids[: prefix_len + trunc_len]
+        req.fill_len = prefix_len + trunc_len
 
         self.can_run_list.append(req)
 
@@ -681,7 +681,7 @@ class PrefillAdder:
         # Truncate input length to available tokens and update request metadata
         truncated = req.extend_input_len > _rem_tokens
         req.extend_input_len = min(req.extend_input_len, _rem_tokens)
-        req.fill_ids = req.fill_ids[: len(req.prefix_indices) + req.extend_input_len]
+        req.fill_len = len(req.prefix_indices) + req.extend_input_len
         self.can_run_list.append(req)
 
         # Update budget: reserve max_new_tokens only if not truncated
@@ -721,7 +721,7 @@ class PrefillAdder:
 
         truncated = req.extend_input_len > _rem_tokens
         req.set_extend_input_len(min(req.extend_input_len, _rem_tokens))
-        req.fill_ids = req.fill_ids[: len(req.prefix_indices) + req.extend_input_len]
+        req.fill_len = len(req.prefix_indices) + req.extend_input_len
         self.can_run_list.append(req)
         self._update_prefill_budget(
             0,
@@ -843,7 +843,7 @@ class PrefillAdder:
             trunc_len = self.rem_chunk_tokens
 
             req.set_extend_input_len(trunc_len)
-            req.fill_ids = req.fill_ids[:trunc_len]
+            req.fill_len = trunc_len
             self.can_run_list.append(req)
             self.new_chunked_req = req
             self._update_prefill_budget(0, trunc_len, 0, req.retracted_stain)
@@ -932,7 +932,7 @@ class PrefillAdder:
                     )
                 )
                 req.prefix_indices = torch.cat([req.prefix_indices, new_indices])
-                req.set_extend_input_len(len(req.fill_ids) - len(req.prefix_indices))
+                req.set_extend_input_len(req.fill_len - len(req.prefix_indices))
                 prefix_len = len(req.prefix_indices)
                 req.cache_protected_len = prefix_len
 
@@ -999,7 +999,7 @@ class PrefillAdder:
 
                 # Chunked prefill
                 req.set_extend_input_len(trunc_len)
-                req.fill_ids = req.fill_ids[: len(req.prefix_indices) + trunc_len]
+                req.fill_len = len(req.prefix_indices) + trunc_len
 
                 self.can_run_list.append(req)
                 self.new_chunked_req = req

python/sglang/srt/managers/scheduler.py

@@ -941,9 +941,9 @@ class Scheduler(
         # req_pool_idx from prepare_for_extend). Used to gate the
         # stash_chunked_request call at the top of get_next_batch_to_run:
         # if add_chunked_req early-returned under hybrid-SWA pressure,
-        # the req_pool_idx was already freed and fill_ids was reset by
+        # the req_pool_idx was already freed and the full_untruncated_fill_ids
-        # init_next_round_input, so running stash would double-free and
+        # was rebuilt by init_next_round_input, so running stash would
-        # corrupt prefix_indices.
+        # double-free and corrupt prefix_indices.
         self._chunked_req_scheduled_last_iter = False
         self.is_mixed_chunk = (
             self.chunked_prefill_size is not None
@@ -2159,7 +2159,7 @@ class Scheduler(
             if last_host_node.backuped or last_host_node is self.tree_cache.root_node:
                 last_hash = last_host_node.get_last_hash_value()
                 matched_len = len(req.prefix_indices) + req.host_hit_length
-                new_input_tokens = req.fill_ids[matched_len:]
+                new_input_tokens = req.get_fill_ids()[matched_len:]
 
                 prefix_keys = (
                     last_host_node.get_prefix_hash_values(last_host_node.parent)

python/sglang/srt/managers/scheduler_components/logprob_result_processor.py

@@ -184,7 +184,7 @@ class SchedulerLogprobResultProcessor:
             i: The request index in a batch.
             req: The request. Input logprobs inside req are modified as a
                 consequence of the API
-            fill_ids: The prefill ids processed.
+            logprob_pt: Pointer into the prefill ids processed.
             output: Logit processor output that's used to compute input logprobs
             last_prefill_chunk: True if it is the last prefill (when chunked).
                 Some of input logprob operation should only happen at the last

python/sglang/srt/managers/scheduler_pp_mixin.py

@@ -606,9 +606,10 @@ class SchedulerPPMixin:
                     origin_input_ids=input_ids,
                     sampling_params=sampling_params,
                 )
-                req.fill_ids = req.origin_input_ids
+                req.full_untruncated_fill_ids = req.origin_input_ids
+                req.fill_len = len(req.full_untruncated_fill_ids)
                 req.logprob_start_len = -1
-                req.set_extend_input_len(len(req.fill_ids) - len(req.prefix_indices))
+                req.set_extend_input_len(req.fill_len - len(req.prefix_indices))
 
                 # Prepare batch
                 batch = ScheduleBatch.init_new(
@@ -621,7 +622,7 @@ class SchedulerPPMixin:
                     self.spec_algorithm,
                 )
 
-                current_seq_len = len(req.fill_ids)
+                current_seq_len = req.fill_len
 
                 if is_dp_attention_enabled():
                     # For profiling, we only have one request on PP0
@@ -685,7 +686,7 @@ class SchedulerPPMixin:
                 # Release KV cache
                 if req.req_pool_idx is not None:
                     kv_indices = self.req_to_token_pool.req_to_token[
-                        req.req_pool_idx, : len(req.fill_ids)
+                        req.req_pool_idx, : req.fill_len
                     ]
                     self.token_to_kv_pool_allocator.free(kv_indices)
                     self.req_to_token_pool.free(req)

python/sglang/srt/mem_cache/chunk_cache.py

@@ -86,7 +86,7 @@ class ChunkCache(BasePrefixCache):
 
     def cache_unfinished_req(self, req: Req, chunked=False):
         kv_indices = self.req_to_token_pool.req_to_token[
-            req.req_pool_idx, : len(req.fill_ids)
+            req.req_pool_idx, : req.fill_len
         ]
         # `req.prefix_indices` will be used in `PrefillAdder::add_chunked_req` later
         req.prefix_indices = kv_indices.to(dtype=torch.int64, copy=True)

python/sglang/srt/mem_cache/mamba_radix_cache.py

@@ -611,14 +611,14 @@ class MambaRadixCache(KVCacheEventMixin, BasePrefixCache):
 
         def _skip_cache_unfinished_req(req: Req) -> None:
             kv_indices = self.req_to_token_pool.req_to_token[
-                req.req_pool_idx, : len(req.fill_ids)
+                req.req_pool_idx, : req.fill_len
             ]
 
             # `req.prefix_indices` will be used in `PrefillAdder::add_chunked_req` later
             req.prefix_indices = kv_indices.to(dtype=torch.int64, copy=True)
             return
 
-        token_ids = req.fill_ids
+        token_ids = req.get_fill_ids()
         cache_len = (
             req.mamba_last_track_seqlen
             if self.enable_mamba_extra_buffer

python/sglang/srt/mem_cache/radix_cache.py

@@ -466,7 +466,7 @@ class RadixCache(KVCacheEventMixin, BasePrefixCache):
         if self.disable:
             return
 
-        token_ids = req.fill_ids
+        token_ids = req.get_fill_ids()
         kv_indices = self.req_to_token_pool.req_to_token[
             req.req_pool_idx, : len(token_ids)
         ]

python/sglang/srt/mem_cache/radix_cache_cpp.py

@@ -210,7 +210,7 @@ class RadixCacheCpp(BasePrefixCache):
     def cache_unfinished_req(self, req: Req, chunked=False):
         """Cache request when it is unfinished."""
         assert req.req_pool_idx is not None
-        token_ids = req.fill_ids
+        token_ids = req.get_fill_ids()
         prefill_len = len(token_ids)  # prefill only (maybe chunked)
         kv_indices = self.req_to_token_pool.req_to_token[
             req.req_pool_idx, :prefill_len

python/sglang/srt/mem_cache/swa_radix_cache.py

@@ -488,14 +488,14 @@ class SWARadixCache(KVCacheEventMixin, BasePrefixCache):
         """Cache request when it is unfinished."""
         if self.disable:
             kv_indices = self.req_to_token_pool.req_to_token[
-                req.req_pool_idx, : len(req.fill_ids)
+                req.req_pool_idx, : req.fill_len
             ]
 
             # `req.prefix_indices` will be used in `PrefillAdder::add_chunked_req` later
             req.prefix_indices = kv_indices
             return
 
-        token_ids = req.fill_ids
+        token_ids = req.get_fill_ids()
         kv_indices = self.req_to_token_pool.req_to_token[
             req.req_pool_idx, : len(token_ids)
         ]

python/sglang/srt/mem_cache/unified_radix_cache.py

@@ -722,7 +722,7 @@ class UnifiedRadixCache(KVCacheEventMixin, BasePrefixCache):
         if self.session.try_cache_unfinished_req(req, chunked=chunked, **kwargs):
             return
 
-        token_ids = req.fill_ids
+        token_ids = req.get_fill_ids()
 
         if self.disable:
             kv_indices = self.req_to_token_pool.req_to_token[

python/sglang/srt/session/streaming_session.py

@@ -244,9 +244,9 @@ class StreamingSession(BasePrefixCache):
         req = params.req
         slot.restore_to_req(req)
 
-        # token_ids = fill_ids[:input_len-1] (1-token logit reserve already
+        # token_ids = get_fill_ids()[:input_len-1] (1-token logit reserve
-        # applied). min handles retract retry where committed_len can
+        # already applied). min handles retract retry where committed_len
-        # exceed len(token_ids) by 1.
+        # can exceed len(token_ids) by 1.
         prefix_len = min(req.kv_committed_len, len(params.key.token_ids))
 
         # Streaming sessions are append-only (session_controller rollback
@@ -353,7 +353,7 @@ class StreamingSession(BasePrefixCache):
             return False
         if chunked:
             kv_indices = self.req_to_token_pool.req_to_token[
-                req.req_pool_idx, : len(req.fill_ids)
+                req.req_pool_idx, : req.fill_len
             ]
             req.prefix_indices = kv_indices.to(dtype=torch.int64, copy=True)
             return True

test/manual/test_forward_split_prefill.py

@@ -95,9 +95,10 @@ class TestForwardSplitPrefill(CustomTestCase):
                 origin_input_ids=array("q", input_ids[i]),
                 sampling_params=sampling_params,
             )
-            req.fill_ids = req.origin_input_ids
+            req.full_untruncated_fill_ids = req.origin_input_ids
+            req.fill_len = len(req.full_untruncated_fill_ids)
             req.logprob_start_len = -1
-            req.set_extend_input_len(len(req.fill_ids) - len(req.prefix_indices))
+            req.set_extend_input_len(req.fill_len - len(req.prefix_indices))
             reqs.append(req)
 
         # Create dummy tree_cache for tests (no prefix caching, just allocation)

test/registered/input_embedding/test_input_embeds_chunked.py

@@ -3,14 +3,14 @@
 Covers two bugs with the same crash signature
 (RuntimeError: shape mismatch in set_kv_buffer) but opposite polarity:
 
-- Chunked prefill truncation (#20376): PrefillAdder truncates fill_ids and
+- Chunked prefill truncation (#20376): PrefillAdder shrinks fill_len and
   extend_input_len on chunk overflow but not input_embeds, so the full array
   flows through while out_cache_loc is sized for the truncated length.
   Polarity: cache_k > loc.
 
-- Retraction with output_ids (#14110): after retraction, fill_ids includes
+- Retraction with output_ids (#14110): after retraction, get_fill_ids()
-  accumulated output_ids but input_embeds only covers origin_input_ids.
+  includes accumulated output_ids but input_embeds only covers
-  Polarity: cache_k < loc.
+  origin_input_ids. Polarity: cache_k < loc.
 """
 
 import unittest
@@ -162,8 +162,8 @@ class TestInputEmbedsChunkedAndRetract(CustomTestCase):
         SGLANG_TEST_RETRACT forces retraction every few scheduler iterations.
         Combined with ignore_eos and a reasonable max_new_tokens, at least one
         request is retracted mid-decode with non-empty output_ids, then
-        re-prefilled. Pre-#14110 this crashes (cache_k < loc) because fill_ids
+        re-prefilled. Pre-#14110 this crashes (cache_k < loc) because the
-        includes output_ids but input_embeds does not.
+        filled token sequence includes output_ids but input_embeds does not.
         """
         text = "The quick brown fox jumps over the lazy dog. " * 4
         embeds = _embeds_for(text)

test/registered/unit/managers/test_hisparse_unit.py

@@ -9,6 +9,7 @@ Tests cover:
 
 import os
 import unittest
+from array import array
 from types import SimpleNamespace
 
 import torch
@@ -210,7 +211,8 @@ class TestHiSparseUnit(unittest.TestCase):
         self.req_to_token_pool.write((req.req_pool_idx, slice(0, len(kv_loc))), kv_loc)
         req.kv_allocated_len = fill_len
         req.kv_committed_len = fill_len
-        req.fill_ids = list(range(fill_len))
+        req.full_untruncated_fill_ids = array("q", range(fill_len))
+        req.fill_len = fill_len
         return kv_loc
 
     # ==================================================================

test/registered/unit/managers/test_prefill_adder.py

@@ -386,7 +386,8 @@ class TestPrefillAdder(CustomTestCase):
         req1.extend_input_len = 56
         req1.host_hit_length = 0
         req1.prefix_indices = []
-        req1.fill_ids = list(range(56))
+        req1.full_untruncated_fill_ids = list(range(56))
+        req1.fill_len = 56
         req1.last_node = MagicMock()
         req1.sampling_params.ignore_eos = False
 
@@ -420,7 +421,8 @@ class TestPrefillAdder(CustomTestCase):
         req2.extend_input_len = 56
         req2.host_hit_length = 0
         req2.prefix_indices = []
-        req2.fill_ids = list(range(56))
+        req2.full_untruncated_fill_ids = list(range(56))
+        req2.fill_len = 56
         req2.last_node = MagicMock()
         req2.sampling_params.ignore_eos = False
 
@@ -437,7 +439,8 @@ class TestPrefillAdder(CustomTestCase):
         req3.extend_input_len = 3
         req3.host_hit_length = 0
         req3.prefix_indices = []
-        req3.fill_ids = list(range(3))
+        req3.full_untruncated_fill_ids = list(range(3))
+        req3.fill_len = 3
         req3.last_node = MagicMock()
         req3.sampling_params.ignore_eos = False
 
@@ -473,7 +476,8 @@ class TestPrefillAdder(CustomTestCase):
         req = self.create_mock_req("chunked", priority=0, max_new_tokens=128)
         req.extend_input_len = extend_input_len
         req.prefix_indices = []
-        req.fill_ids = list(range(extend_input_len))
+        req.full_untruncated_fill_ids = list(range(extend_input_len))
+        req.fill_len = extend_input_len
         req.set_extend_input_len = MagicMock()
         return adder, req
 

test/registered/unit/managers/test_scheduler_chunked_req_gate.py

@@ -30,7 +30,8 @@ def _make_req(
     req.rid = "test-req"
     req.origin_input_ids = array("q", fill_ids)
     req.output_ids = array("q")
-    req.fill_ids = array("q", fill_ids)
+    req.full_untruncated_fill_ids = array("q", fill_ids)
+    req.fill_len = len(req.full_untruncated_fill_ids)
     req.prefix_indices = prefix_indices
     req.req_pool_idx = req_pool_idx
     req.extend_input_len = extend_input_len

test/registered/unit/mem_cache/test_decode_radix_lock_ref.py

@@ -67,7 +67,8 @@ class MockReq:
     """Minimal mock Req with fields needed by cache_unfinished/finished_req."""
 
     def __init__(self, fill_ids, req_pool_idx=0, cache_protected_len=0, last_node=None):
-        self.fill_ids = array("q", fill_ids)
+        self.full_untruncated_fill_ids = array("q", fill_ids)
+        self.fill_len = len(self.full_untruncated_fill_ids)
         self.origin_input_ids = array(
             "q", fill_ids[:-1] if len(fill_ids) > 1 else fill_ids
         )
@@ -82,6 +83,9 @@ class MockReq:
         self.kv_allocated_len = len(fill_ids)
         self.kv_committed_freed = False
 
+    def get_fill_ids(self):
+        return self.full_untruncated_fill_ids[: self.fill_len]
+
     def pop_committed_kv_cache(self):
         self.kv_committed_freed = True
         return self.kv_committed_len

test/registered/unit/mem_cache/test_unified_radix_cache_bench.py

@@ -637,7 +637,8 @@ def bench_cache_finished(
         req = env.make_req()
         req.origin_input_ids = array("q", seq)
         req.output_ids = array("q")
-        req.fill_ids = array("q", seq)
+        req.full_untruncated_fill_ids = array("q", seq)
+        req.fill_len = len(req.full_untruncated_fill_ids)
         req.last_node = node
         req.cache_protected_len = matched_len
         req.kv_committed_len = len(seq)

test/registered/unit/mem_cache/test_unified_radix_cache_unittest.py

@@ -798,7 +798,8 @@ class UnifiedRadixCacheSuite:
         req.cache_protected_len = 0
         req.swa_uuid_for_lock = None
         req.extra_key = None
-        req.fill_ids = array("q", input_ids + output_ids)
+        req.full_untruncated_fill_ids = array("q", input_ids + output_ids)
+        req.fill_len = len(req.full_untruncated_fill_ids)
         if self.cfg.has_mamba:
             req.mamba_last_track_seqlen = kv_len
 
@@ -821,8 +822,9 @@ class UnifiedRadixCacheSuite:
         output_ids = self._make_seq(2000, 7)
         req.origin_input_ids = array("q", prompt_ids)
         req.output_ids = array("q", output_ids)
-        req.fill_ids = array("q", prompt_ids + output_ids)
+        req.full_untruncated_fill_ids = array("q", prompt_ids + output_ids)
-        kv_len = len(req.fill_ids)
+        req.fill_len = len(req.full_untruncated_fill_ids)
+        kv_len = req.fill_len
         kv_indices = self._alloc(allocator, kv_len)
         req_to_token_pool.write((req.req_pool_idx, slice(0, kv_len)), kv_indices)
         req.kv_committed_len = kv_len
@@ -875,7 +877,8 @@ class UnifiedRadixCacheSuite:
         req.cache_protected_len = 0
         req.swa_uuid_for_lock = None
         req.extra_key = None
-        req.fill_ids = array("q", tokens)
+        req.full_untruncated_fill_ids = array("q", tokens)
+        req.fill_len = len(req.full_untruncated_fill_ids)
 
         avail_before = allocator.available_size()
         tree.cache_finished_req(req, is_insert=False)
@@ -892,7 +895,8 @@ class UnifiedRadixCacheSuite:
         tokens = self._make_seq(1, 3)
         req.origin_input_ids = array("q", tokens)
         req.output_ids = array("q")
-        req.fill_ids = array("q", tokens)
+        req.full_untruncated_fill_ids = array("q", tokens)
+        req.fill_len = len(req.full_untruncated_fill_ids)
         kv_len = len(tokens)
         kv_indices = self._alloc(allocator, kv_len)
         req_to_token_pool.write((req.req_pool_idx, slice(0, kv_len)), kv_indices)
@@ -1026,7 +1030,8 @@ class UnifiedRadixCacheSuite:
         req.cache_protected_len = 0
         req.swa_uuid_for_lock = None
         req.extra_key = None
-        req.fill_ids = array("q", input_ids)
+        req.full_untruncated_fill_ids = array("q", input_ids)
+        req.fill_len = len(req.full_untruncated_fill_ids)
         if self.cfg.has_mamba:
             req.mamba_last_track_seqlen = kv_len
 

test/registered/unit/utils/test_common.py

@@ -14,8 +14,8 @@ register_cuda_ci(est_time=5, stage="base-b", runner_config="1-gpu-small")
 class TestFlattenArraysToInt64Tensor(CustomTestCase):
     """`flatten_arrays_to_int64_tensor` is invoked by `prepare_for_extend`
     to build the per-batch input_ids tensor (pinned, async H2D) from a
-    list of array.array('q') per-req fill_ids slices. Tests the full
+    list of array.array('q') per-req get_fill_ids() slices. Tests the
-    matrix of (device, pin) the production code paths through.
+    full matrix of (device, pin) the production code paths through.
     """
 
     DEVICES = ("cpu", "cuda")