Hi Muchun, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on next-20210310] [cannot apply to hnaz-linux-mm/master arm64/for-next/core tip/x86/mm linus/master v5.12-rc2 v5.12-rc1 v5.11 v5.12-rc2] [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/Muchun-Song/mm-bootmem_info-mark-register_page_bootmem_info_section-__init/20210310-161619 base: b01d57bfdc41c8f635b08b8a5af8a31217d46936 config: x86_64-randconfig-c002-20210310 (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): # https://github.com/0day-ci/linux/commit/92924b23a9f6de5bb478cea033cd2d39c227a6c5 git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Muchun-Song/mm-bootmem_info-mark-register_page_bootmem_info_section-__init/20210310-161619 git checkout 92924b23a9f6de5bb478cea033cd2d39c227a6c5 # save the attached .config to linux build tree make W=1 ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All warnings (new ones prefixed by >>): >> mm/sparse-vmemmap.c:159:13: warning: no previous prototype for 'arch_free_vmemmap_page' [-Wmissing-prototypes] 159 | void __weak arch_free_vmemmap_page(struct page *page) | ^~~~~~~~~~~~~~~~~~~~~~ vim +/arch_free_vmemmap_page +159 mm/sparse-vmemmap.c 158 > 159 void __weak arch_free_vmemmap_page(struct page *page) 160 { 161 free_reserved_page(page); 162 } 163 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org