[UWP] RuntimeBroker.exe using gigs of memory

Question

RuntimeBroker.exe seems to be a go-between for UWP accessing the file system.

Here is a UWP app button click done in c++/winrt. Just use it to open an entire drive or c:\program files and RuntimeBroker.exe can use more than a few gigs. Takes a very long time.

    Windows::Foundation::IAsyncAction MainPage::ClickHandler(IInspectable const&, RoutedEventArgs const&)
    {

        std::wstring  _debugMessage =  L"ClickHandler started";
        OutputDebugString(_debugMessage.data());

        Windows::Storage::Pickers::FolderPicker _folderPicker;
                                                _folderPicker.FileTypeFilter().Append(winrt::hstring(L"*"));

        winrt::Windows::Storage::StorageFolder    _folder = NULL;

        _folder = co_await _folderPicker.PickSingleFolderAsync();


        co_await winrt::resume_background();

        auto _storageFiles = _folder.GetFilesAsync(Windows::Storage::Search::CommonFileQuery::OrderByName).get();

        _debugMessage = std::to_wstring(_storageFiles.Size());
        OutputDebugString(_debugMessage.data());

        co_await winrt::resume_foreground(this->Dispatcher());

        myButton().Content(box_value(L"Clicked"));
    }

Runtimebroker.exe seems to hold about 60k per StorageItem held. It is probably therefore holding a thumbnail pic (just a guess), which is much bigger than many of the files. Horrendously inefficient.

Answer 1

When we hold on to a StorageFile object in a UWP app, Windows holds on to about 60k per object in RuntimeBroker.exe.
It seems that the only solution is to not hold very many StorageFile objects.

Answer 2

You can try following method of StorageFileQueryResult: https://learn.microsoft.com/en-us/uwp/api/windows.storage.search.storagefilequeryresult.getfilesasync?view=winrt-19041#Windows_Storage_Search_StorageFileQueryResult_GetFilesAsync_System_UInt32_System_UInt32_

It could help to process files page by page and maybe it will help RuntimeBroker to cleanup memory on the fly.