Fix global fence in Kokkos::resize(DynRankView) (kokkos#6184)

* Fix global fence in Kokkos::resize(DynRankView)

* Add test case

* Comment on the intent of the test and guard for existence of SharedSpace

* Guard execution of test differently

* Loop in reverse order on the host to increase chances for detecting a missing fence

* Test with 1k elements, improve name of the test

containers/src/Kokkos_DynRankView.hpp

@@ -2302,9 +2302,10 @@ inline void impl_resize(const Impl::ViewCtorProp<ViewCtorArgs...>& arg_prop,
   if constexpr (alloc_prop_input::has_execution_space)
     Kokkos::Impl::DynRankViewRemap<drview_type, drview_type>(
         Impl::get_property<Impl::ExecutionSpaceTag>(prop_copy), v_resized, v);
-  else
+  else {
     Kokkos::Impl::DynRankViewRemap<drview_type, drview_type>(v_resized, v);
-
+    Kokkos::fence("Kokkos::resize(DynRankView)");
+  }
   v = v_resized;
 }
 

containers/unit_tests/TestDynViewAPI_rank12345.hpp

@@ -20,4 +20,56 @@ namespace Test {
 TEST(TEST_CATEGORY, dyn_rank_view_api_operator_rank12345) {
   TestDynViewAPI<double, TEST_EXECSPACE>::run_operator_test_rank12345();
 }
+
+template <typename SharedMemorySpace>
+void test_dyn_rank_view_resize() {
+  int n = 1000;
+  Kokkos::DynRankView<double, SharedMemorySpace> device_view("device view", n);
+  // Make sure we don't deallocate memory in Kokkos::resize
+  auto device_view_copy = device_view;
+
+  Kokkos::resize(device_view, 2 * n);
+
+  // Loop in reverse to increase likelihood of missing fence detection assuming
+  // that resize copies values in order.
+  for (int i = 2 * n - 1; i >= 0; --i) device_view(i) = i + 1;
+
+  Kokkos::fence();
+
+  // Check that Kokkos::resize completed before setting the values on the host
+  // manually (possibly because of missing fences).
+  for (int i = 0; i < 2 * n; ++i) ASSERT_EQ(device_view(i), i + 1);
+}
+
+template <typename SharedMemorySpace>
+void test_dyn_rank_view_realloc() {
+  int n = 1000;
+  Kokkos::DynRankView<double, SharedMemorySpace> device_view("device view", n);
+  // Make sure we don't deallocate memory in Kokkos::realloc
+  auto device_view_copy = device_view;
+
+  Kokkos::realloc(device_view, 2 * n);
+
+  // Loop in reverse to increase likelihood of missing fence detection assuming
+  // that realloc sets values in order.
+  for (int i = 2 * n - 1; i >= 0; --i) device_view(i) = i + 1;
+
+  Kokkos::fence();
+
+  // Check that Kokkos::realloc completed before setting the values on the host
+  // manually (possibly because of missing fences).
+  for (int i = 0; i < 2 * n; ++i) ASSERT_EQ(device_view(i), i + 1);
+}
+
+#ifdef KOKKOS_HAS_SHARED_SPACE
+TEST(TEST_CATEGORY, dyn_rank_view_check_fence_resize_realloc) {
+  if constexpr (std::is_same_v<TEST_EXECSPACE, Kokkos::DefaultExecutionSpace>) {
+    test_dyn_rank_view_resize<Kokkos::SharedSpace>();
+    test_dyn_rank_view_realloc<Kokkos::SharedSpace>();
+  } else {
+    GTEST_SKIP() << "skipping since not default execution space";
+  }
+}
+#endif
+
 }  // namespace Test