Re: [PATCH] mm/huge_memory.c: introduce folio_split_unmapped

[Zi Yan]

On 14 Nov 2025, at 21:33, Balbir Singh wrote:

> On 11/15/25 13:15, kernel test robot wrote:
>> Hi Balbir,
>>
>> kernel test robot noticed the following build warnings:
>>
>> [auto build test WARNING on akpm-mm/mm-everything]
>>
>> url:    https://github.com/intel-lab-lkp/linux/commits/Balbir-Singh/mm-huge_memory-c-introduce-folio_split_unmapped/20251114-093541
>> base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
>> patch link:    https://lore.kernel.org/r/20251114012228.2634882-1-balbirs%40nvidia.com
>> patch subject: [PATCH] mm/huge_memory.c: introduce folio_split_unmapped
>> config: arm64-randconfig-002-20251115 (https://download.01.org/0day-ci/archive/20251115/202511151007.F1gixfc8-lkp@xxxxxxxxx/config)
>> compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff)
>> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251115/202511151007.F1gixfc8-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/202511151007.F1gixfc8-lkp@xxxxxxxxx/
>>
>> All warnings (new ones prefixed by >>):
>>
>>>> mm/huge_memory.c:3751:6: warning: variable 'nr_shmem_dropped' set but not used [-Wunused-but-set-variable]
>>     3751 |         int nr_shmem_dropped = 0;
>>          |             ^
>>    1 warning generated.
>>
>>
>> vim +/nr_shmem_dropped +3751 mm/huge_memory.c
>>
>
> [...]
>
> Thanks for the report, I'll send an updated version after I investigate it

nr_shmem_dropped is updated in __folio_freeze_and_split_unmapped() but
is used in its caller. It needs to be passed into __folio_freeze_and_split_unmapped().

--
Best Regards,
Yan, Zi