Re: [PATCH v2 1/5] memcg: add per-memcg ksm_rmap_items stat

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

Hi,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]
[also build test ERROR on tj-cgroup/for-next linus/master v6.17-rc5 next-20250912]
[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/xu-xin16-zte-com-cn/memcg-add-per-memcg-ksm_rmap_items-stat/20250914-181132
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20250914180351288rcLuZnPAMUej48nuTc7KV%40zte.com.cn
patch subject: [PATCH v2 1/5] memcg: add per-memcg ksm_rmap_items stat
config: parisc-randconfig-001-20250914 (https://download.01.org/0day-ci/archive/20250914/202509142147.WQI0impC-lkp@intel.com/config)
compiler: hppa-linux-gcc (GCC) 8.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250914/202509142147.WQI0impC-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/202509142147.WQI0impC-lkp@intel.com/

All errors (new ones prefixed by >>):

   mm/ksm.c: In function 'memcg_stat_ksm_show':
>> mm/ksm.c:3345:2: error: implicit declaration of function 'seq_buf_printf'; did you mean 'seq_bprintf'? [-Werror=implicit-function-declaration]
     seq_buf_printf(s, "ksm_rmap_items %lu\n", ksm_stat.ksm_rmap_items);
     ^~~~~~~~~~~~~~
     seq_bprintf
   cc1: some warnings being treated as errors


vim +3345 mm/ksm.c

  3329	
  3330	/* Show the ksm statistic count at memory.stat under cgroup mountpoint */
  3331	void memcg_stat_ksm_show(struct mem_cgroup *memcg, struct seq_buf *s)
  3332	{
  3333		struct memcg_ksm_stat ksm_stat;
  3334	
  3335		if (mem_cgroup_is_root(memcg)) {
  3336			/* Just use the global counters when root memcg */
  3337			ksm_stat.ksm_rmap_items = ksm_rmap_items;
  3338		} else {
  3339			/* Initialization */
  3340			ksm_stat.ksm_rmap_items = 0;
  3341			/* Summing all processes'ksm statistic items */
  3342			mem_cgroup_scan_tasks(memcg, evaluate_memcg_ksm_stat, &ksm_stat);
  3343		}
  3344		/* Print memcg ksm statistic items */
> 3345		seq_buf_printf(s, "ksm_rmap_items %lu\n", ksm_stat.ksm_rmap_items);
  3346	}
  3347	#endif
  3348	

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