On 10 Sep 2025, at 22:12, Lance Yang wrote: > Hi Yafang, > > On 2025/9/11 01:27, kernel test robot wrote: >> 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@xxxxxxxxx/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@xxxxxxxxx/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@xxxxxxxxx> >> | Closes: https://lore.kernel.org/oe-kbuild-all/202509110109.PSgSHb31-lkp@xxxxxxxxx/ >> >> 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. > > Oops, seems like hugepage_pmd_enabled() and __khugepaged_enter() are only > available when CONFIG_TRANSPARENT_HUGEPAGE is enabled ;) > >> >> >> 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 > > So, let's wrap the new logic in an #ifdef CONFIG_TRANSPARENT_HUGEPAGE block. > > diff --git a/kernel/sys.c b/kernel/sys.c > index a1c1e8007f2d..c8600e017933 100644 > --- a/kernel/sys.c > +++ b/kernel/sys.c > @@ -2495,10 +2495,13 @@ static int prctl_set_thp_disable(bool thp_disable, unsigned long flags, > mm_flags_clear(MMF_DISABLE_THP_EXCEPT_ADVISED, mm); > } > > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE > if (!mm_flags_test(MMF_DISABLE_THP_COMPLETELY, mm) && > !mm_flags_test(MMF_VM_HUGEPAGE, mm) && > hugepage_pmd_enabled()) > __khugepaged_enter(mm); > +#endif > + > mmap_write_unlock(current->mm); > return 0; > } Or in the header file, #ifdef CONFIG_TRANSPARENT_HUGEPAGE ... #else bool hugepage_pmd_enabled() { return false; } int __khugepaged_enter(struct mm_struct *mm) { return 0; } #endif Best Regards, Yan, Zi
