Pad the list extents to account for interleaved storage

cpp/include/cuvs/neighbors/common.hpp

@@ -853,14 +853,6 @@ using enable_if_valid_list_t = typename enable_if_valid_list<ListT, T>::type;
  *       `cuvs::neighbors::ivf_pq::helpers::resize_list` which handle type casting internally.
  */
 template <typename ListT>
-CUVS_EXPORT void resize_list(raft::resources const& res,
-                             std::shared_ptr<ListT>& orig_list,  // NOLINT
-                             const typename ListT::spec_type& spec,
-                             typename ListT::size_type new_used_size,
-                             typename ListT::size_type old_logical_size,
-                             typename ListT::size_type old_used_size);
-
-template <typename ListT>
 CUVS_EXPORT void resize_list(raft::resources const& res,
                              std::shared_ptr<ListT>& orig_list,  // NOLINT
                              const typename ListT::spec_type& spec,

cpp/include/cuvs/neighbors/ivf_flat.hpp

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: Copyright (c) 2024-2026, NVIDIA CORPORATION.
+ * SPDX-FileCopyrightText: Copyright (c) 2024-2026, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
  * SPDX-License-Identifier: Apache-2.0
  */
 
@@ -11,6 +11,7 @@
 #include <cuvs/neighbors/common.hpp>
 #include <raft/core/host_mdarray.hpp>
 #include <raft/core/host_mdspan.hpp>
+#include <raft/util/integer_utils.hpp>
 #include <sstream>
 #include <string>
 
@@ -110,7 +111,8 @@ struct list_spec {
   /** Determine the extents of an array enough to hold a given amount of data. */
   constexpr auto make_list_extents(SizeT n_rows) const -> list_extents
   {
-    return raft::make_extents<SizeT>(n_rows, dim);
+    return raft::make_extents<SizeT>(raft::round_up_safe<SizeT>(n_rows, SizeT{kIndexGroupSize}),
+                                     dim);
   }
 };
 

cpp/include/cuvs/neighbors/ivf_sq.hpp

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: Copyright (c) 2026, NVIDIA CORPORATION.
+ * SPDX-FileCopyrightText: Copyright (c) 2026, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
  * SPDX-License-Identifier: Apache-2.0
  */
 
@@ -118,7 +118,8 @@ struct CUVS_EXPORT list_spec {
   constexpr auto make_list_extents(SizeT n_rows) const -> list_extents
   {
     uint32_t padded = raft::round_up_safe<uint32_t>(dim, kVecLen);
-    return raft::make_extents<SizeT>(n_rows, padded);
+    return raft::make_extents<SizeT>(raft::round_up_safe<SizeT>(n_rows, SizeT{kIndexGroupSize}),
+                                     padded);
   }
 };
 

cpp/src/neighbors/ivf_flat/ivf_flat_build.cuh

@@ -282,12 +282,8 @@ void extend(raft::resources const& handle,
     raft::resource::sync_stream(handle);
     auto& lists = index->lists();
     for (uint32_t label = 0; label < n_lists; label++) {
-      ivf::resize_list(handle,
-                       lists[label],
-                       list_device_spec,
-                       new_list_sizes[label],
-                       old_list_sizes[label],
-                       raft::Pow2<kIndexGroupSize>::roundUp(old_list_sizes[label]));
+      ivf::resize_list(
+        handle, lists[label], list_device_spec, new_list_sizes[label], old_list_sizes[label]);
     }
   }
   // Update the pointers and the sizes

cpp/src/neighbors/ivf_list.cuh

@@ -66,17 +66,13 @@ CUVS_EXPORT void resize_list(raft::resources const& res,
                              std::shared_ptr<ListT>& orig_list,  // NOLINT
                              const typename ListT::spec_type& spec,
                              typename ListT::size_type new_used_size,
-                             typename ListT::size_type old_logical_size,
                              typename ListT::size_type old_used_size)
 {
-  // old_logical_size is the previous visible size from this index's list_sizes().
-  // old_used_size is the old allocation copy extent and may include padded slots
-  // required by interleaved list layouts.
   bool skip_resize = false;
   if (orig_list) {
     if (new_used_size <= orig_list->indices.extent(0)) {
-      auto shared_list_size = old_logical_size;
-      if (new_used_size <= old_logical_size ||
+      auto shared_list_size = old_used_size;
+      if (new_used_size <= old_used_size ||
           orig_list->size.compare_exchange_strong(shared_list_size, new_used_size)) {
         // We don't need to resize the list if:
         //  1. The list exists
@@ -108,16 +104,6 @@ CUVS_EXPORT void resize_list(raft::resources const& res,
   new_list.swap(orig_list);
 }
 
-template <typename ListT>
-CUVS_EXPORT void resize_list(raft::resources const& res,
-                             std::shared_ptr<ListT>& orig_list,  // NOLINT
-                             const typename ListT::spec_type& spec,
-                             typename ListT::size_type new_used_size,
-                             typename ListT::size_type old_used_size)
-{
-  resize_list(res, orig_list, spec, new_used_size, old_used_size, old_used_size);
-}
-
 template <typename ListT>
 enable_if_valid_list_t<ListT> serialize_list(const raft::resources& handle,
                                              std::ostream& os,

cpp/src/neighbors/ivf_sq/ivf_sq_build.cuh

@@ -354,12 +354,8 @@ void extend_inplace(raft::resources const& handle,
     raft::resource::sync_stream(handle);
     auto& lists = index->lists();
     for (uint32_t label = 0; label < n_lists; label++) {
-      ivf::resize_list(handle,
-                       lists[label],
-                       list_device_spec,
-                       new_list_sizes[label],
-                       old_list_sizes[label],
-                       raft::Pow2<kIndexGroupSize>::roundUp(old_list_sizes[label]));
+      ivf::resize_list(
+        handle, lists[label], list_device_spec, new_list_sizes[label], old_list_sizes[label]);
     }
   }
   ivf::detail::recompute_internal_state(handle, *index);