Don't copy.

dmlc · Sep 25, 2020 · cca9ec0 · cca9ec0
1 parent b4fba09
commit cca9ec0
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Showing 2 changed files with 9 additions and 3 deletions.
diff --git a/src/common/device_helpers.cuh b/src/common/device_helpers.cuh
@@ -538,6 +538,10 @@ void CopyDeviceSpanToVector(std::vector<T> *dst, xgboost::common::Span<const T>
 
 template <class HContainer, class DContainer>
 void CopyToD(HContainer const &h, DContainer *d) {
+  if (h.empty()) {
+    d->clear();
+    return;
+  }
   d->resize(h.size());
   using HVT = std::remove_cv_t<typename HContainer::value_type>;
   using DVT = std::remove_cv_t<typename DContainer::value_type>;

diff --git a/src/tree/updater_gpu_hist.cu b/src/tree/updater_gpu_hist.cu
@@ -457,9 +457,11 @@ struct GPUHistMakerDevice {
     dh::caching_device_vector<uint32_t> d_categories;
     dh::caching_device_vector<RegTree::Segment> d_categories_segments;
 
-    dh::CopyToD(h_split_types, &d_split_types);
-    dh::CopyToD(categories, &d_categories);
-    dh::CopyToD(categories_segments, &d_categories_segments);
+    if (!categories.empty()) {
+      dh::CopyToD(h_split_types, &d_split_types);
+      dh::CopyToD(categories, &d_categories);
+      dh::CopyToD(categories_segments, &d_categories_segments);
+    }
 
     if (row_partitioner->GetRows().size() != p_fmat->Info().num_row_) {
       row_partitioner.reset();  // Release the device memory first before reallocating