[GPUPS]Fix psgpuwrapper initialization (#44468)

* Update ps_gpu_wrapper.h

* Update ps_gpu_wrapper.h

* Update ps_gpu_wrapper.cc

paddle/fluid/framework/fleet/ps_gpu_wrapper.cc

@@ -95,6 +95,7 @@ int AfsWrapper::mv(const std::string& old_path, const std::string& dest_path) {
 
 std::shared_ptr<PSGPUWrapper> PSGPUWrapper::s_instance_ = NULL;
 bool PSGPUWrapper::is_initialized_ = false;
+std::mutex PSGPUWrapper::ins_mutex;
 #ifdef PADDLE_WITH_PSLIB
 void PSGPUWrapper::InitAfsApi(const std::string& fs_name,
                               const std::string& fs_user,

paddle/fluid/framework/fleet/ps_gpu_wrapper.h

@@ -20,6 +20,7 @@ limitations under the License. */
 #include <ctime>
 #include <map>
 #include <memory>
+#include <mutex>
 #include <random>
 #include <string>
 #include <unordered_map>
@@ -429,8 +430,11 @@ class PSGPUWrapper {
 
   // PSGPUWrapper singleton
   static std::shared_ptr<PSGPUWrapper> GetInstance() {
-    if (NULL == s_instance_) {
-      s_instance_.reset(new paddle::framework::PSGPUWrapper());
+    {
+      std::lock_guard<std::mutex> lk(ins_mutex);
+      if (NULL == s_instance_) {
+        s_instance_.reset(new paddle::framework::PSGPUWrapper());
+      }
     }
     return s_instance_;
   }
@@ -537,6 +541,7 @@ class PSGPUWrapper {
 
  private:
   static std::shared_ptr<PSGPUWrapper> s_instance_;
+  static std::mutex ins_mutex;
   Dataset* dataset_;
 #ifdef PADDLE_WITH_PSLIB
   paddle::ps::AfsApiWrapper afs_handler_;