Re: [PATCH 2/3] mm: shrinker: optimize the allocation of shrinker_info when setting cgroup_memory_nokmem

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

Hi Haifeng,

kernel test robot noticed the following build errors:

[auto build test ERROR on linus/master]
[also build test ERROR on v7.0-rc2 next-20260306]
[cannot apply to akpm-mm/mm-everything]
[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/Haifeng-Xu/mm-shrinker-introduce-new-function-get_shrinker_id/20260306-160247
base:   linus/master
patch link:    https://lore.kernel.org/r/20260306075757.198887-3-haifeng.xu%40shopee.com
patch subject: [PATCH 2/3] mm: shrinker: optimize the allocation of shrinker_info when setting cgroup_memory_nokmem
config: i386-randconfig-002-20260307 (https://download.01.org/0day-ci/archive/20260308/202603080606.UQEPDmnB-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/20260308/202603080606.UQEPDmnB-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/202603080606.UQEPDmnB-lkp@intel.com/

All errors (new ones prefixed by >>):

>> mm/huge_memory.c:4355:38: error: no member named 'id' in 'struct shrinker'
    4355 |                         int id = deferred_split_shrinker->id;
         |                                  ~~~~~~~~~~~~~~~~~~~~~~~  ^
>> mm/huge_memory.c:4358:35: error: no member named 'nonslab_id' in 'struct shrinker'
    4358 |                                 id = deferred_split_shrinker->nonslab_id;
         |                                      ~~~~~~~~~~~~~~~~~~~~~~~  ^
   2 errors generated.


vim +4355 mm/huge_memory.c

  4307	
  4308	/* partially_mapped=false won't clear PG_partially_mapped folio flag */
  4309	void deferred_split_folio(struct folio *folio, bool partially_mapped)
  4310	{
  4311		struct deferred_split *ds_queue;
  4312		unsigned long flags;
  4313	
  4314		/*
  4315		 * Order 1 folios have no space for a deferred list, but we also
  4316		 * won't waste much memory by not adding them to the deferred list.
  4317		 */
  4318		if (folio_order(folio) <= 1)
  4319			return;
  4320	
  4321		if (!partially_mapped && !split_underused_thp)
  4322			return;
  4323	
  4324		/*
  4325		 * Exclude swapcache: originally to avoid a corrupt deferred split
  4326		 * queue. Nowadays that is fully prevented by memcg1_swapout();
  4327		 * but if page reclaim is already handling the same folio, it is
  4328		 * unnecessary to handle it again in the shrinker, so excluding
  4329		 * swapcache here may still be a useful optimization.
  4330		 */
  4331		if (folio_test_swapcache(folio))
  4332			return;
  4333	
  4334		ds_queue = folio_split_queue_lock_irqsave(folio, &flags);
  4335		if (partially_mapped) {
  4336			if (!folio_test_partially_mapped(folio)) {
  4337				folio_set_partially_mapped(folio);
  4338				if (folio_test_pmd_mappable(folio))
  4339					count_vm_event(THP_DEFERRED_SPLIT_PAGE);
  4340				count_mthp_stat(folio_order(folio), MTHP_STAT_SPLIT_DEFERRED);
  4341				mod_mthp_stat(folio_order(folio), MTHP_STAT_NR_ANON_PARTIALLY_MAPPED, 1);
  4342	
  4343			}
  4344		} else {
  4345			/* partially mapped folios cannot become non-partially mapped */
  4346			VM_WARN_ON_FOLIO(folio_test_partially_mapped(folio), folio);
  4347		}
  4348		if (list_empty(&folio->_deferred_list)) {
  4349			struct mem_cgroup *memcg;
  4350	
  4351			memcg = folio_split_queue_memcg(folio, ds_queue);
  4352			list_add_tail(&folio->_deferred_list, &ds_queue->split_queue);
  4353			ds_queue->split_queue_len++;
  4354			if (memcg) {
> 4355				int id = deferred_split_shrinker->id;
  4356	
  4357				if (!memcg_kmem_online() &&  memcg != root_mem_cgroup)
> 4358					id = deferred_split_shrinker->nonslab_id;
  4359	
  4360				set_shrinker_bit(memcg, folio_nid(folio), id);
  4361			}
  4362		}
  4363		split_queue_unlock_irqrestore(ds_queue, flags);
  4364	}
  4365	

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