reproduce (this is a W=1 build):
        # https://github.com/gourryinverse/linux/commit/bc46f47dbd9b1e365d338f89a0ab10eadce13982
        git remote add gourryinverse https://github.com/gourryinverse/linux
        git fetch --no-tags gourryinverse gourry_pagecache
        git checkout bc46f47dbd9b1e365d338f89a0ab10eadce13982
        # 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 mm/