Hi Yafang,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on akpm-mm/mm-everything]

url:    https://github.com/intel-lab-lkp/linux/commits/Yafang-Shao/mm-page_ext-split-page_ext-flags/20221217-190044
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20221217105833.24851-3-laoar.shao%40gmail.com
patch subject: [PATCH -mm 2/2] mm: page_idle: split 32bit page_idle's flag from the common flags
config: microblaze-randconfig-r006-20221217
compiler: microblaze-linux-gcc (GCC) 12.1.0
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
        # https://github.com/intel-lab-lkp/linux/commit/b2ccea224a74e091007c4c772b78b8163bb11b6c
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Yafang-Shao/mm-page_ext-split-page_ext-flags/20221217-190044
        git checkout b2ccea224a74e091007c4c772b78b8163bb11b6c
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=microblaze olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=microblaze SHELL=/bin/bash

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   microblaze-linux-ld: mm/filemap.o: in function `__filemap_get_folio':
>> include/linux/page_idle.h:24: undefined reference to `page_idle_ops'
   microblaze-linux-ld: mm/swap.o: in function `folio_mark_accessed':
>> include/linux/page_idle.h:24: undefined reference to `page_idle_ops'
   microblaze-linux-ld: mm/rmap.o: in function `folio_referenced_one':
>> include/linux/page_idle.h:24: undefined reference to `page_idle_ops'
>> microblaze-linux-ld: include/linux/page_idle.h:24: undefined reference to `page_idle_ops'
   microblaze-linux-ld: mm/migrate.o: in function `folio_migrate_flags':
>> include/linux/page_idle.h:24: undefined reference to `page_idle_ops'
   microblaze-linux-ld: mm/migrate.o:include/linux/page_idle.h:24: more undefined references to `page_idle_ops' follow


vim +24 include/linux/page_idle.h

    20	
    21	extern struct page_ext_operations page_idle_ops;
    22	static inline struct page_idle *get_page_idle(struct page_ext *page_ext)
    23	{
  > 24		return (void *)page_ext + page_idle_ops.offset;
    25	}
    26	

-- 
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https://01.org/lkp