Replace remaining uses of device_vector (#8343)

Replaces `device_vector` with `device_uvector` in decomp_test.cu (now .cpp) and quantile.cu.

Also updates `DEVELOPER_GUIDE.md` to advise against using `device_vector`.

Closes #2631

Authors:
  - Mark Harris (https://github.com/harrism)

Approvers:
  - Ram (Ramakrishna Prabhu) (https://github.com/rgsl888prabhu)
  - Nghia Truong (https://github.com/ttnghia)

URL: #8343

cpp/docs/DEVELOPER_GUIDE.md

@@ -458,8 +458,12 @@ int host_value = int_scalar.value();
 Allocates a specified number of elements of the specified type. If no initialization value is 
 provided, all elements are default initialized (this incurs a kernel launch).
 
-**Note**: `rmm::device_vector<T>` is not yet updated to use `device_memory_resource`s, but support 
-is forthcoming. Likewise, `device_vector` operations cannot be stream ordered.
+**Note**: We have removed all usage of `rmm::device_vector` and `thrust::device_vector` from
+libcudf, and you should not use it in new code in libcudf without careful consideration. Instead, 
+use `rmm::device_uvector` along with the utility factories in `device_factories.hpp`. These 
+utilities enable creation of `uvector`s from host-side vectors, or creating zero-initialized
+`uvector`s, so that they are as convenient to use as `device_vector`. Avoiding `device_vector` has
+a number of benefits, as described in the folling section on `rmm::device_uvector`.
 
 #### `rmm::device_uvector<T>`
 
@@ -468,7 +472,9 @@ differences:
 - As an optimization, elements are uninitialized and no synchronization occurs at construction.
 This limits the types `T` to trivially copyable types.
 - All operations are stream ordered (i.e., they accept a `cuda_stream_view` specifying the stream 
-on which the operation is performed).
+on which the operation is performed). This improves safety when using non-default streams.
+- `device_uvector.hpp` does not include any `__device__` code, unlike `thrust/device_vector.hpp`, 
+  which means `device_uvector`s can be used in `.cpp` files, rather than just in `.cu` files.
 
 ```c++
 cuda_stream s;

cpp/src/quantiles/quantile.cu

@@ -21,13 +21,15 @@
 #include <cudf/detail/null_mask.hpp>
 #include <cudf/detail/nvtx/ranges.hpp>
 #include <cudf/detail/sorting.hpp>
+#include <cudf/detail/utilities/vector_factories.hpp>
 #include <cudf/dictionary/detail/iterator.cuh>
 #include <cudf/dictionary/dictionary_column_view.hpp>
 #include <cudf/table/table_view.hpp>
 #include <cudf/types.hpp>
 #include <cudf/utilities/error.hpp>
 
 #include <rmm/cuda_stream_view.hpp>
+#include <rmm/device_uvector.hpp>
 
 #include <memory>
 #include <vector>
@@ -76,12 +78,13 @@ struct quantile_functor {
     auto d_input  = column_device_view::create(input, stream);
     auto d_output = mutable_column_device_view::create(output->mutable_view());
 
-    rmm::device_vector<double> q_device{q};
+    auto q_device = cudf::detail::make_device_uvector_sync(q);
 
     if (!cudf::is_dictionary(input.type())) {
       auto sorted_data =
         thrust::make_permutation_iterator(input.data<StorageType>(), ordered_indices);
-      thrust::transform(q_device.begin(),
+      thrust::transform(rmm::exec_policy(),
+                        q_device.begin(),
                         q_device.end(),
                         d_output->template begin<StorageResult>(),
                         [sorted_data, interp = interp, size = size] __device__(double q) {
@@ -90,7 +93,8 @@ struct quantile_functor {
     } else {
       auto sorted_data = thrust::make_permutation_iterator(
         dictionary::detail::make_dictionary_iterator<T>(*d_input), ordered_indices);
-      thrust::transform(q_device.begin(),
+      thrust::transform(rmm::exec_policy(),
+                        q_device.begin(),
                         q_device.end(),
                         d_output->template begin<StorageResult>(),
                         [sorted_data, interp = interp, size = size] __device__(double q) {

cpp/tests/CMakeLists.txt

@@ -180,7 +180,7 @@ ConfigureTest(INTEROP_TEST
 
 ###################################################################################################
 # - io tests --------------------------------------------------------------------------------------
-ConfigureTest(DECOMPRESSION_TEST io/comp/decomp_test.cu)
+ConfigureTest(DECOMPRESSION_TEST io/comp/decomp_test.cpp)
 
 ConfigureTest(CSV_TEST io/csv_test.cpp)
 ConfigureTest(ORC_TEST io/orc_test.cpp)

cpp/tests/io/comp/decomp_test.cu → cpp/tests/io/comp/decomp_test.cpp

@@ -18,10 +18,11 @@
 
 #include <cudf_test/base_fixture.hpp>
 
-#include <vector>
-
+#include <rmm/cuda_stream_view.hpp>
 #include <rmm/device_buffer.hpp>
-#include <rmm/device_vector.hpp>
+#include <rmm/device_uvector.hpp>
+
+#include <vector>
 
 /**
  * @brief Base test fixture for decompression
@@ -36,9 +37,6 @@ struct DecompressTest : public cudf::test::BaseFixture {
     ASSERT_CUDA_SUCCEEDED(cudaMallocHost((void**)&inf_args, sizeof(cudf::io::gpu_inflate_input_s)));
     ASSERT_CUDA_SUCCEEDED(
       cudaMallocHost((void**)&inf_stat, sizeof(cudf::io::gpu_inflate_status_s)));
-
-    d_inf_args.resize(1);
-    d_inf_stat.resize(1);
   }
 
   void TearDown() override
@@ -64,19 +62,22 @@ struct DecompressTest : public cudf::test::BaseFixture {
     inf_args->dstDevice = static_cast<uint8_t*>(dst.data());
     inf_args->srcSize   = src.size();
     inf_args->dstSize   = dst.size();
-    ASSERT_CUDA_SUCCEEDED(cudaMemcpyAsync(d_inf_args.data().get(),
+    rmm::device_uvector<cudf::io::gpu_inflate_input_s> d_inf_args(1, rmm::cuda_stream_default);
+    rmm::device_uvector<cudf::io::gpu_inflate_status_s> d_inf_stat(1, rmm::cuda_stream_default);
+    ASSERT_CUDA_SUCCEEDED(cudaMemcpyAsync(d_inf_args.data(),
                                           inf_args,
                                           sizeof(cudf::io::gpu_inflate_input_s),
                                           cudaMemcpyHostToDevice,
                                           0));
-    ASSERT_CUDA_SUCCEEDED(cudaMemcpyAsync(d_inf_stat.data().get(),
+    ASSERT_CUDA_SUCCEEDED(cudaMemcpyAsync(d_inf_stat.data(),
                                           inf_stat,
                                           sizeof(cudf::io::gpu_inflate_status_s),
                                           cudaMemcpyHostToDevice,
                                           0));
-    ASSERT_CUDA_SUCCEEDED(static_cast<Decompressor*>(this)->dispatch());
+    ASSERT_CUDA_SUCCEEDED(
+      static_cast<Decompressor*>(this)->dispatch(d_inf_args.data(), d_inf_stat.data()));
     ASSERT_CUDA_SUCCEEDED(cudaMemcpyAsync(inf_stat,
-                                          d_inf_stat.data().get(),
+                                          d_inf_stat.data(),
                                           sizeof(cudf::io::gpu_inflate_status_s),
                                           cudaMemcpyDeviceToHost,
                                           0));
@@ -87,41 +88,41 @@ struct DecompressTest : public cudf::test::BaseFixture {
 
   cudf::io::gpu_inflate_input_s* inf_args  = nullptr;
   cudf::io::gpu_inflate_status_s* inf_stat = nullptr;
-  rmm::device_vector<cudf::io::gpu_inflate_input_s> d_inf_args;
-  rmm::device_vector<cudf::io::gpu_inflate_status_s> d_inf_stat;
 };
 
 /**
  * @brief Derived fixture for GZIP decompression
  */
 struct GzipDecompressTest : public DecompressTest<GzipDecompressTest> {
-  cudaError_t dispatch()
+  cudaError_t dispatch(cudf::io::gpu_inflate_input_s* d_inf_args,
+                       cudf::io::gpu_inflate_status_s* d_inf_stat)
   {
-    return cudf::io::gpuinflate(d_inf_args.data().get(), d_inf_stat.data().get(), 1, 1);
+    return cudf::io::gpuinflate(d_inf_args, d_inf_stat, 1, 1);
   }
 };
 
 /**
  * @brief Derived fixture for Snappy decompression
  */
 struct SnappyDecompressTest : public DecompressTest<SnappyDecompressTest> {
-  cudaError_t dispatch()
+  cudaError_t dispatch(cudf::io::gpu_inflate_input_s* d_inf_args,
+                       cudf::io::gpu_inflate_status_s* d_inf_stat)
   {
-    return cudf::io::gpu_unsnap(d_inf_args.data().get(), d_inf_stat.data().get(), 1);
+    return cudf::io::gpu_unsnap(d_inf_args, d_inf_stat, 1);
   }
 };
 
 /**
  * @brief Derived fixture for Brotli decompression
  */
 struct BrotliDecompressTest : public DecompressTest<BrotliDecompressTest> {
-  cudaError_t dispatch()
+  cudaError_t dispatch(cudf::io::gpu_inflate_input_s* d_inf_args,
+                       cudf::io::gpu_inflate_status_s* d_inf_stat)
   {
     rmm::device_buffer d_scratch{cudf::io::get_gpu_debrotli_scratch_size(1),
                                  rmm::cuda_stream_default};
 
-    return cudf::io::gpu_debrotli(
-      d_inf_args.data().get(), d_inf_stat.data().get(), d_scratch.data(), d_scratch.size(), 1);
+    return cudf::io::gpu_debrotli(d_inf_args, d_inf_stat, d_scratch.data(), d_scratch.size(), 1);
   }
 };