remove in no sampling.

Author: trivialfis

src/tree/gpu_hist/gradient_based_sampler.cu

@@ -146,11 +146,12 @@ class PoissonSampling : public thrust::binary_function<GradientPair, size_t, Gra
   CombineGradientPair combine_;
 };
 
-NoSampling::NoSampling(EllpackPageImpl const* page) : page_(page) {}
+NoSampling::NoSampling(BatchParam batch_param) : batch_param_(std::move(batch_param)) {}
 
-GradientBasedSample NoSampling::Sample(Context const*, common::Span<GradientPair> gpair,
+GradientBasedSample NoSampling::Sample(Context const* ctx, common::Span<GradientPair> gpair,
                                        DMatrix* dmat) {
-  return {dmat->Info().num_row_, page_, gpair};
+  auto page = (*dmat->GetBatches<EllpackPage>(ctx, batch_param_).begin()).Impl();
+  return {dmat->Info().num_row_, page, gpair};
 }
 
 ExternalMemoryNoSampling::ExternalMemoryNoSampling(Context const* ctx, EllpackPageImpl const* page,
@@ -349,7 +350,7 @@ GradientBasedSampler::GradientBasedSampler(Context const* ctx, EllpackPageImpl c
     if (is_external_memory) {
       strategy_.reset(new ExternalMemoryNoSampling(ctx, page, n_rows, batch_param));
     } else {
-      strategy_.reset(new NoSampling(page));
+      strategy_.reset(new NoSampling(batch_param));
     }
   }
 }

src/tree/gpu_hist/gradient_based_sampler.cuh

@@ -32,12 +32,12 @@ class SamplingStrategy {
 /*! \brief No sampling in in-memory mode. */
 class NoSampling : public SamplingStrategy {
  public:
-  explicit NoSampling(EllpackPageImpl const* page);
+  explicit NoSampling(BatchParam batch_param);
   GradientBasedSample Sample(Context const* ctx, common::Span<GradientPair> gpair,
                              DMatrix* dmat) override;
 
  private:
-  EllpackPageImpl const* page_;
+  BatchParam batch_param_;
 };
 
 /*! \brief No sampling in external memory mode. */