reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://github.com/gourryinverse/linux/commit/17f6241916fff43de0664b150b9a319636071ae7
        git remote add gourryinverse https://github.com/gourryinverse/linux
        git fetch --no-tags gourryinverse gourry_vmscan_cpuset
        git checkout 17f6241916fff43de0664b150b9a319636071ae7
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-8.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=s390 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-8.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash kernel/cgroup/