Re: [PATCH v2 4/4] mm: thp: reparent the split queue during memcg offline

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

Hi Qi,

kernel test robot noticed the following build errors:

[auto build test ERROR on next-20250922]
[also build test ERROR on v6.17-rc7]
[cannot apply to akpm-mm/mm-everything rppt-memblock/for-next rppt-memblock/fixes linus/master v6.17-rc7 v6.17-rc6 v6.17-rc5]
[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/20250923-171935
base:   next-20250922
patch link:    https://lore.kernel.org/r/55370bda7b2df617033ac12116c1712144bb7591.1758618527.git.zhengqi.arch%40bytedance.com
patch subject: [PATCH v2 4/4] mm: thp: reparent the split queue during memcg offline
config: riscv-randconfig-001-20250924 (https://download.01.org/0day-ci/archive/20250924/202509242123.QwwFy7gc-lkp@intel.com/config)
compiler: riscv64-linux-gcc (GCC) 8.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250924/202509242123.QwwFy7gc-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/202509242123.QwwFy7gc-lkp@intel.com/

All errors (new ones prefixed by >>):

   mm/huge_memory.c: In function 'reparent_deferred_split_queue':
>> mm/huge_memory.c:4302:42: error: dereferencing pointer to incomplete type 'struct mem_cgroup'
     struct deferred_split *ds_queue = &memcg->deferred_split_queue;
                                             ^~

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for ARCH_HAS_ELF_CORE_EFLAGS
   Depends on [n]: BINFMT_ELF [=n] && ELF_CORE [=n]
   Selected by [y]:
   - RISCV [=y]


vim +4302 mm/huge_memory.c

  4298	
  4299	void reparent_deferred_split_queue(struct mem_cgroup *memcg)
  4300	{
  4301		struct mem_cgroup *parent = parent_mem_cgroup(memcg);
> 4302		struct deferred_split *ds_queue = &memcg->deferred_split_queue;
  4303		struct deferred_split *parent_ds_queue = &parent->deferred_split_queue;
  4304		int nid;
  4305	
  4306		spin_lock_irq(&ds_queue->split_queue_lock);
  4307		spin_lock_nested(&parent_ds_queue->split_queue_lock, SINGLE_DEPTH_NESTING);
  4308	
  4309		if (!ds_queue->split_queue_len)
  4310			goto unlock;
  4311	
  4312		list_splice_tail_init(&ds_queue->split_queue, &parent_ds_queue->split_queue);
  4313		parent_ds_queue->split_queue_len += ds_queue->split_queue_len;
  4314		ds_queue->split_queue_len = 0;
  4315		/* Mark the ds_queue dead */
  4316		ds_queue->is_dying = true;
  4317	
  4318		for_each_node(nid)
  4319			set_shrinker_bit(parent, nid, shrinker_id(deferred_split_shrinker));
  4320	
  4321	unlock:
  4322		spin_unlock(&parent_ds_queue->split_queue_lock);
  4323		spin_unlock_irq(&ds_queue->split_queue_lock);
  4324	}
  4325	

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