Re: [PATCH v2 1/4] Make enter_lazy_tlb inline on x86

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

Hi Xie,

kernel test robot noticed the following build errors:

[auto build test ERROR on tip/sched/core]
[also build test ERROR on tip/x86/core tip/x86/mm s390/features perf-tools-next/perf-tools-next tip/perf/core perf-tools/perf-tools linus/master v6.18-rc4 next-20251107]
[cannot apply to acme/perf/core tip/timers/nohz]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Xie-Yuanbin/Make-enter_lazy_tlb-inline-on-x86/20251109-013003
base:   tip/sched/core
patch link:    https://lore.kernel.org/r/20251108172346.263590-2-qq570070308%40gmail.com
patch subject: [PATCH v2 1/4] Make enter_lazy_tlb inline on x86
config: x86_64-kexec (https://download.01.org/0day-ci/archive/20251109/202511092219.73aMMES4-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/20251109/202511092219.73aMMES4-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/202511092219.73aMMES4-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from arch/x86/kvm/../../../virt/kvm/async_pf.c:14:
   In file included from include/linux/mmu_context.h:5:
>> arch/x86/include/asm/mmu_context.h:155:20: error: use of undeclared identifier 'cpu_tlbstate'
     155 |         if (this_cpu_read(cpu_tlbstate.loaded_mm) == &init_mm)
         |                           ^
>> arch/x86/include/asm/mmu_context.h:155:20: error: use of undeclared identifier 'cpu_tlbstate'
>> arch/x86/include/asm/mmu_context.h:155:20: error: use of undeclared identifier 'cpu_tlbstate'
>> arch/x86/include/asm/mmu_context.h:155:20: error: use of undeclared identifier 'cpu_tlbstate'
>> arch/x86/include/asm/mmu_context.h:155:20: error: use of undeclared identifier 'cpu_tlbstate'
>> arch/x86/include/asm/mmu_context.h:155:20: error: use of undeclared identifier 'cpu_tlbstate'
>> arch/x86/include/asm/mmu_context.h:155:20: error: use of undeclared identifier 'cpu_tlbstate'
>> arch/x86/include/asm/mmu_context.h:155:20: error: use of undeclared identifier 'cpu_tlbstate'
>> arch/x86/include/asm/mmu_context.h:155:20: error: use of undeclared identifier 'cpu_tlbstate'
>> arch/x86/include/asm/mmu_context.h:155:20: error: use of undeclared identifier 'cpu_tlbstate'
>> arch/x86/include/asm/mmu_context.h:155:20: error: use of undeclared identifier 'cpu_tlbstate'
>> arch/x86/include/asm/mmu_context.h:158:17: error: use of undeclared identifier 'cpu_tlbstate_shared'
     158 |         this_cpu_write(cpu_tlbstate_shared.is_lazy, true);
         |                        ^
>> arch/x86/include/asm/mmu_context.h:158:17: error: use of undeclared identifier 'cpu_tlbstate_shared'
>> arch/x86/include/asm/mmu_context.h:158:17: error: use of undeclared identifier 'cpu_tlbstate_shared'
>> arch/x86/include/asm/mmu_context.h:158:17: error: use of undeclared identifier 'cpu_tlbstate_shared'
>> arch/x86/include/asm/mmu_context.h:158:17: error: use of undeclared identifier 'cpu_tlbstate_shared'
>> arch/x86/include/asm/mmu_context.h:158:17: error: use of undeclared identifier 'cpu_tlbstate_shared'
>> arch/x86/include/asm/mmu_context.h:158:17: error: use of undeclared identifier 'cpu_tlbstate_shared'
>> arch/x86/include/asm/mmu_context.h:158:17: error: use of undeclared identifier 'cpu_tlbstate_shared'
   fatal error: too many errors emitted, stopping now [-ferror-limit=]
   20 errors generated.


vim +/cpu_tlbstate +155 arch/x86/include/asm/mmu_context.h

   138	
   139	/*
   140	 * Please ignore the name of this function.  It should be called
   141	 * switch_to_kernel_thread().
   142	 *
   143	 * enter_lazy_tlb() is a hint from the scheduler that we are entering a
   144	 * kernel thread or other context without an mm.  Acceptable implementations
   145	 * include doing nothing whatsoever, switching to init_mm, or various clever
   146	 * lazy tricks to try to minimize TLB flushes.
   147	 *
   148	 * The scheduler reserves the right to call enter_lazy_tlb() several times
   149	 * in a row.  It will notify us that we're going back to a real mm by
   150	 * calling switch_mm_irqs_off().
   151	 */
   152	#define enter_lazy_tlb enter_lazy_tlb
   153	static __always_inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
   154	{
 > 155		if (this_cpu_read(cpu_tlbstate.loaded_mm) == &init_mm)
   156			return;
   157	
 > 158		this_cpu_write(cpu_tlbstate_shared.is_lazy, true);
   159	}
   160	

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