fix compile errors

paddle/fluid/operators/reader/create_double_buffer_reader_op.cc

@@ -20,8 +20,8 @@ namespace paddle {
 namespace operators {
 namespace reader {
 
-static constexpr size_t kChannelSize = 2;
-static constexpr size_t kCacheSize = 4;  // kChannelSize + 2
+static constexpr size_t kCacheSize = 2;
+static constexpr size_t kChannelSize = 0;  // kCacheSize - 2
 
 class DoubleBufferReader : public framework::DecoratedReader {
  public:
@@ -36,7 +36,7 @@ class DoubleBufferReader : public framework::DecoratedReader {
       ReaderBase* reader, platform::Place target_place = platform::CPUPlace())
       : DecoratedReader(reader), place_(target_place) {
 #ifdef PADDLE_WITH_CUDA
-    for (size_t i = 0; i < kChannelSize + 2; ++i) {
+    for (size_t i = 0; i < kCacheSize; ++i) {
       if (platform::is_gpu_place(place_)) {
         ctxs_.emplace_back(new platform::CUDADeviceContext(
             boost::get<platform::CUDAPlace>(place_)));
@@ -51,17 +51,17 @@ class DoubleBufferReader : public framework::DecoratedReader {
   void ReInit() override;
 
   void StartPrefetcher() {
-    buffer_ = framework::MakeChannel<Item>(kChannelSize);
+    channel_ = framework::MakeChannel<Item>(kChannelSize);
     prefetcher_ = std::thread([this] { PrefetchThreadFunc(); });
   }
 
   void EndPrefetcher() {
-    buffer_->Close();
-    if (prefecther_.joinable()) {
+    channel_->Close();
+    if (prefetcher_.joinable()) {
       prefetcher_.join();
     }
-    delete buffer_;
-    buffer_ = nullptr;
+    delete channel_;
+    channel_ = nullptr;
   }
 
   ~DoubleBufferReader() { EndPrefetcher(); }
@@ -70,7 +70,7 @@ class DoubleBufferReader : public framework::DecoratedReader {
   void PrefetchThreadFunc();
 
   std::thread prefetcher_;
-  framework::Channel<Item>* buffer_;
+  framework::Channel<Item>* channel_;
   platform::Place place_;
   std::vector<std::unique_ptr<platform::DeviceContext>> ctxs_;
 };
@@ -127,9 +127,9 @@ class CreateDoubleBufferReaderOpMaker : public DecoratedReaderMakerBase {
 };
 
 bool DoubleBufferReader::HasNext() const {
-  while (!buffer_->IsClosed() && !buffer_->CanReceive()) {
+  while (!channel_->IsClosed() && !channel_->CanReceive()) {
   }
-  return buffer_->CanReceive()
+  return channel_->CanReceive();
 }
 
 void DoubleBufferReader::ReadNext(std::vector<framework::LoDTensor>* out) {
@@ -138,8 +138,8 @@ void DoubleBufferReader::ReadNext(std::vector<framework::LoDTensor>* out) {
   }
 
   Item batch;
-  buffer_->Receive(&batch);
-  *out = batch.payload_;
+  channel_->Receive(&batch);
+  *out = batch.payloads_;
   if (batch.ctx_) {
     batch.ctx_->Wait();
   }
@@ -167,26 +167,26 @@ void DoubleBufferReader::PrefetchThreadFunc() {
       gpu_batch.resize(cpu_batch.size());
       for (size_t i = 0; i < cpu_batch.size(); ++i) {
         framework::TensorCopy(cpu_batch[i], place_, *gpu_ctx, &gpu_batch[i]);
-        gpu_batch[i].set_lod(batch.payloads_[i].lod());
+        gpu_batch[i].set_lod(cpu_batch[i].lod());
       }
-      batch.payload_ = gpu_batch;
+      batch.payloads_ = gpu_batch;
       batch.ctx_ = gpu_ctx;
     } else {
       // CPUPlace
-      batch.payload_ = cpu_batch;
+      batch.payloads_ = cpu_batch;
     }
     ++cached_tensor_id;
     cached_tensor_id %= kCacheSize;
 
     try {
-      buffer_->Send(&batch);
+      channel_->Send(&batch);
     } catch (paddle::platform::EnforceNotMet e) {
       VLOG(5) << "WARNING: The double buffer channel has been closed. The "
                  "prefetch thread will terminate.";
       break;
     }
   }
-  buffer_->Close();
+  channel_->Close();
   VLOG(5) << "Prefetch thread terminates.";
 }