reproduce (this is a W=1 build):
        # https://github.com/gestionlin/linux/commit/a4f123e5e9347f8f9302bcc6b0a05c8a5a9ff4b8
        git remote add linyunsheng https://github.com/gestionlin/linux.git
        git fetch --no-tags linyunsheng page_bulk_alloc_opt
        git checkout a4f123e5e9347f8f9302bcc6b0a05c8a5a9ff4b8
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=x86_64 olddefconfig
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash fs/xfs/