Re: [PATCH v7 mm-new 01/10] mm: thp: remove disabled task from khugepaged_mm_slot

[kernel test robot <lkp@intel.com>]

Hi Yafang,

kernel test robot noticed the following build errors:

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

url:    https://github.com/intel-lab-lkp/linux/commits/Yafang-Shao/mm-thp-remove-disabled-task-from-khugepaged_mm_slot/20250910-144850
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20250910024447.64788-2-laoar.shao%40gmail.com
patch subject: [PATCH v7 mm-new 01/10] mm: thp: remove disabled task from khugepaged_mm_slot
config: x86_64-allnoconfig (https://download.01.org/0day-ci/archive/20250911/202509110109.PSgSHb31-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250911/202509110109.PSgSHb31-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202509110109.PSgSHb31-lkp@intel.com/

All errors (new ones prefixed by >>):

>> kernel/sys.c:2500:6: error: call to undeclared function 'hugepage_pmd_enabled'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    2500 |             hugepage_pmd_enabled())
         |             ^
>> kernel/sys.c:2501:3: error: call to undeclared function '__khugepaged_enter'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    2501 |                 __khugepaged_enter(mm);
         |                 ^
   2 errors generated.


vim +/hugepage_pmd_enabled +2500 kernel/sys.c

  2471	
  2472	static int prctl_set_thp_disable(bool thp_disable, unsigned long flags,
  2473					 unsigned long arg4, unsigned long arg5)
  2474	{
  2475		struct mm_struct *mm = current->mm;
  2476	
  2477		if (arg4 || arg5)
  2478			return -EINVAL;
  2479	
  2480		/* Flags are only allowed when disabling. */
  2481		if ((!thp_disable && flags) || (flags & ~PR_THP_DISABLE_EXCEPT_ADVISED))
  2482			return -EINVAL;
  2483		if (mmap_write_lock_killable(current->mm))
  2484			return -EINTR;
  2485		if (thp_disable) {
  2486			if (flags & PR_THP_DISABLE_EXCEPT_ADVISED) {
  2487				mm_flags_clear(MMF_DISABLE_THP_COMPLETELY, mm);
  2488				mm_flags_set(MMF_DISABLE_THP_EXCEPT_ADVISED, mm);
  2489			} else {
  2490				mm_flags_set(MMF_DISABLE_THP_COMPLETELY, mm);
  2491				mm_flags_clear(MMF_DISABLE_THP_EXCEPT_ADVISED, mm);
  2492			}
  2493		} else {
  2494			mm_flags_clear(MMF_DISABLE_THP_COMPLETELY, mm);
  2495			mm_flags_clear(MMF_DISABLE_THP_EXCEPT_ADVISED, mm);
  2496		}
  2497	
  2498		if (!mm_flags_test(MMF_DISABLE_THP_COMPLETELY, mm) &&
  2499		    !mm_flags_test(MMF_VM_HUGEPAGE, mm) &&
> 2500		    hugepage_pmd_enabled())
> 2501			__khugepaged_enter(mm);
  2502		mmap_write_unlock(current->mm);
  2503		return 0;
  2504	}
  2505	

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