Re: [PATCH 2/4] mm: thp: introduce folio_split_queue_lock and its variants

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

Hi Qi,

kernel test robot noticed the following build errors:

[auto build test ERROR on next-20250918]
[also build test ERROR on v6.17-rc6]
[cannot apply to akpm-mm/mm-everything rppt-memblock/for-next rppt-memblock/fixes linus/master v6.17-rc6 v6.17-rc5 v6.17-rc4]
[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/Qi-Zheng/mm-thp-replace-folio_memcg-with-folio_memcg_charged/20250919-115219
base:   next-20250918
patch link:    https://lore.kernel.org/r/eb072e71cc39a0ea915347f39f2af29d2e82897f.1758253018.git.zhengqi.arch%40bytedance.com
patch subject: [PATCH 2/4] mm: thp: introduce folio_split_queue_lock and its variants
config: x86_64-buildonly-randconfig-001-20250920 (https://download.01.org/0day-ci/archive/20250920/202509201640.ikJun7XS-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/20250920/202509201640.ikJun7XS-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/202509201640.ikJun7XS-lkp@intel.com/

All errors (new ones prefixed by >>):

>> mm/huge_memory.c:1105:24: error: incomplete definition of type 'struct mem_cgroup'
    1105 |         queue = memcg ? &memcg->deferred_split_queue :
         |                          ~~~~~^
   include/linux/mm_types.h:35:8: note: forward declaration of 'struct mem_cgroup'
      35 | struct mem_cgroup;
         |        ^
   mm/huge_memory.c:1119:24: error: incomplete definition of type 'struct mem_cgroup'
    1119 |         queue = memcg ? &memcg->deferred_split_queue :
         |                          ~~~~~^
   include/linux/mm_types.h:35:8: note: forward declaration of 'struct mem_cgroup'
      35 | struct mem_cgroup;
         |        ^
   2 errors generated.


vim +1105 mm/huge_memory.c

  1098	
  1099	static struct deferred_split *folio_split_queue_lock(struct folio *folio)
  1100	{
  1101		struct mem_cgroup *memcg;
  1102		struct deferred_split *queue;
  1103	
  1104		memcg = folio_memcg(folio);
> 1105		queue = memcg ? &memcg->deferred_split_queue :
  1106				&NODE_DATA(folio_nid(folio))->deferred_split_queue;
  1107		spin_lock(&queue->split_queue_lock);
  1108	
  1109		return queue;
  1110	}
  1111	

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