Hi David, I love your patch! Perhaps something to improve: [auto build test WARNING on next-20200909] [cannot apply to mmotm/master hnaz-linux-mm/master xen-tip/linux-next powerpc/next linus/master v5.9-rc4 v5.9-rc3 v5.9-rc2 v5.9-rc4] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/David-Hildenbrand/mm-memory_hotp... base: 7204eaa2c1f509066486f488c9dcb065d7484494 :::::: branch date: 9 hours ago :::::: commit date: 9 hours ago config: powerpc-randconfig-r011-20200909 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 0a5dc7effb191eff740e0e7ae7bd8e1f6bdb3ad9) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install powerpc cross compiling tool for clang build # apt-get install binutils-powerpc-linux-gnu # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): In file included from arch/powerpc/kernel/asm-offsets.c:14: In file included from include/linux/compat.h:17: In file included from include/linux/fs.h:15: In file included from include/linux/radix-tree.h:18: In file included from include/linux/xarray.h:14: In file included from include/linux/gfp.h:6: In file included from include/linux/mmzone.h:853: include/linux/memory_hotplug.h:354:55: error: unknown type name 'mhp_t' extern int __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags); ^ include/linux/memory_hotplug.h:355:53: error: unknown type name 'mhp_t' extern int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags); ^ include/linux/memory_hotplug.h:357:11: error: unknown type name 'mhp_t' mhp_t mhp_flags); ^ include/linux/memory_hotplug.h:360:10: error: unknown type name 'mhp_t' mhp_t mhp_flags); ^ In file included from arch/powerpc/kernel/asm-offsets.c:21: _calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED ) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ include/linux/mman.h:115:21: note: expanded from macro '_calc_vm_trans' : ((x) & (bit1)) / ((bit1) / (bit2)))) ^ ~~~~~~~~~~~~~~~~~ include/linux/mman.h:138:9: warning: division by zero is undefined [-Wdivision-by-zero] _calc_vm_trans(flags, MAP_SYNC, VM_SYNC ); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ include/linux/mman.h:115:21: note: expanded from macro '_calc_vm_trans' : ((x) & (bit1)) / ((bit1) / (bit2)))) ^ ~~~~~~~~~~~~~~~~~ 2 warnings and 4 errors generated. make[2]: *** [scripts/Makefile.build:117: arch/powerpc/kernel/asm-offsets.s] Error 1 make[2]: Target '__build' not remade because of errors. make[1]: *** [Makefile:1196: prepare0] Error 2 make[1]: Target 'prepare' not remade because of errors. make: *** [Makefile:185: __sub-make] Error 2 make: Target 'prepare' not remade because of errors. # https://github.com/0day-ci/linux/commit/d88270d1c0783a7f99f24a85692be90fd... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review David-Hildenbrand/mm-memory_hotplug-selective-merging-of-system-ram-resources/20200910-171630 git checkout d88270d1c0783a7f99f24a85692be90fd2ae0d7d vim +137 include/linux/mman.h ^1da177e4c3f41 Linus Torvalds 2005-04-16 128 ^1da177e4c3f41 Linus Torvalds 2005-04-16 129 /* ^1da177e4c3f41 Linus Torvalds 2005-04-16 130 * Combine the mmap "flags" argument into "vm_flags" used internally. ^1da177e4c3f41 Linus Torvalds 2005-04-16 131 */ ^1da177e4c3f41 Linus Torvalds 2005-04-16 132 static inline unsigned long ^1da177e4c3f41 Linus Torvalds 2005-04-16 133 calc_vm_flag_bits(unsigned long flags) ^1da177e4c3f41 Linus Torvalds 2005-04-16 134 { ^1da177e4c3f41 Linus Torvalds 2005-04-16 135 return _calc_vm_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN ) | ^1da177e4c3f41 Linus Torvalds 2005-04-16 136 _calc_vm_trans(flags, MAP_DENYWRITE, VM_DENYWRITE ) | b6fb293f2497a9 Jan Kara 2017-11-01 @137 _calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED ) | b6fb293f2497a9 Jan Kara 2017-11-01 138 _calc_vm_trans(flags, MAP_SYNC, VM_SYNC ); ^1da177e4c3f41 Linus Torvalds 2005-04-16 139 } 00619bcc44d6b7 Jerome Marchand 2013-11-12 140 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org