Re: [PATCH v5 04/10] mm,slub: Use node-notifier instead of memory-notifier

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

Hi Oscar,

kernel test robot noticed the following build errors:

[auto build test ERROR on driver-core/driver-core-testing]
[also build test ERROR on driver-core/driver-core-next driver-core/driver-core-linus rafael-pm/linux-next rafael-pm/bleeding-edge tj-cgroup/for-next linus/master v6.15 next-20250605]
[cannot apply to akpm-mm/mm-everything vbabka-slab/for-next]
[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/Oscar-Salvador/mm-memory_hotplug-Remove-status_change_nid_normal-and-update-documentation/20250605-232305
base:   driver-core/driver-core-testing
patch link:    https://lore.kernel.org/r/20250605142305.244465-5-osalvador%40suse.de
patch subject: [PATCH v5 04/10] mm,slub: Use node-notifier instead of memory-notifier
config: riscv-randconfig-001-20250606 (https://download.01.org/0day-ci/archive/20250606/202506060918.HDCPogq9-lkp@intel.com/config)
compiler: riscv64-linux-gcc (GCC) 11.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250606/202506060918.HDCPogq9-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/202506060918.HDCPogq9-lkp@intel.com/

All errors (new ones prefixed by >>):

   mm/slub.c: In function 'slab_mem_going_online_callback':
>> mm/slub.c:6168:23: error: invalid use of undefined type 'struct node_notify'
    6168 |         int nid = narg->nid;
         |                       ^~
   mm/slub.c: In function 'slab_memory_callback':
   mm/slub.c:6220:14: error: 'NODE_ADDING_FIRST_MEMORY' undeclared (first use in this function)
    6220 |         case NODE_ADDING_FIRST_MEMORY:
         |              ^~~~~~~~~~~~~~~~~~~~~~~~
   mm/slub.c:6220:14: note: each undeclared identifier is reported only once for each function it appears in
   mm/slub.c:6223:14: error: 'NODE_REMOVING_LAST_MEMORY' undeclared (first use in this function)
    6223 |         case NODE_REMOVING_LAST_MEMORY:
         |              ^~~~~~~~~~~~~~~~~~~~~~~~~
   mm/slub.c: In function 'kmem_cache_init':
   mm/slub.c:6300:9: error: implicit declaration of function 'hotplug_node_notifier'; did you mean 'hotplug_memory_notifier'? [-Werror=implicit-function-declaration]
    6300 |         hotplug_node_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
         |         ^~~~~~~~~~~~~~~~~~~~~
         |         hotplug_memory_notifier
   cc1: some warnings being treated as errors


vim +6168 mm/slub.c

  6162	
  6163	static int slab_mem_going_online_callback(void *arg)
  6164	{
  6165		struct kmem_cache_node *n;
  6166		struct kmem_cache *s;
  6167		struct node_notify *narg = arg;
> 6168		int nid = narg->nid;
  6169		int ret = 0;
  6170	
  6171		/*
  6172		 * If the node's memory is already available, then kmem_cache_node is
  6173		 * already created. Nothing to do.
  6174		 */
  6175		if (nid < 0)
  6176			return 0;
  6177	
  6178		/*
  6179		 * We are bringing a node online. No memory is available yet. We must
  6180		 * allocate a kmem_cache_node structure in order to bring the node
  6181		 * online.
  6182		 */
  6183		mutex_lock(&slab_mutex);
  6184		list_for_each_entry(s, &slab_caches, list) {
  6185			/*
  6186			 * The structure may already exist if the node was previously
  6187			 * onlined and offlined.
  6188			 */
  6189			if (get_node(s, nid))
  6190				continue;
  6191			/*
  6192			 * XXX: kmem_cache_alloc_node will fallback to other nodes
  6193			 *      since memory is not yet available from the node that
  6194			 *      is brought up.
  6195			 */
  6196			n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
  6197			if (!n) {
  6198				ret = -ENOMEM;
  6199				goto out;
  6200			}
  6201			init_kmem_cache_node(n);
  6202			s->node[nid] = n;
  6203		}
  6204		/*
  6205		 * Any cache created after this point will also have kmem_cache_node
  6206		 * initialized for the new node.
  6207		 */
  6208		node_set(nid, slab_nodes);
  6209	out:
  6210		mutex_unlock(&slab_mutex);
  6211		return ret;
  6212	}
  6213	

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