Re: [PATCH v4 4/6] mm/damon: introduce DAMOS filter type hugepage

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

Hi Usama,

kernel test robot noticed the following build warnings:

[auto build test WARNING on akpm-mm/mm-everything]

url:    https://github.com/intel-lab-lkp/linux/commits/Usama-Arif/mm-damon-have-damon_get_folio-return-folio-even-for-tail-pages/20250204-065901
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20250203225604.44742-5-usamaarif642%40gmail.com
patch subject: [PATCH v4 4/6] mm/damon: introduce DAMOS filter type hugepage
config: s390-randconfig-001-20250204 (https://download.01.org/0day-ci/archive/20250205/202502050106.VysTkQFY-lkp@intel.com/config)
compiler: s390-linux-gcc (GCC) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250205/202502050106.VysTkQFY-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/202502050106.VysTkQFY-lkp@intel.com/

All warnings (new ones prefixed by >>):

   mm/damon/paddr.c: In function 'damos_pa_filter_match':
>> mm/damon/paddr.c:230:16: warning: unused variable 'folio_sz' [-Wunused-variable]
     230 |         size_t folio_sz;
         |                ^~~~~~~~


vim +/folio_sz +230 mm/damon/paddr.c

   224	
   225	static bool damos_pa_filter_match(struct damos_filter *filter,
   226			struct folio *folio)
   227	{
   228		bool matched = false;
   229		struct mem_cgroup *memcg;
 > 230		size_t folio_sz;
   231	
   232		switch (filter->type) {
   233		case DAMOS_FILTER_TYPE_ANON:
   234			matched = folio_test_anon(folio);
   235			break;
   236		case DAMOS_FILTER_TYPE_MEMCG:
   237			rcu_read_lock();
   238			memcg = folio_memcg_check(folio);
   239			if (!memcg)
   240				matched = false;
   241			else
   242				matched = filter->memcg_id == mem_cgroup_id(memcg);
   243			rcu_read_unlock();
   244			break;
   245		case DAMOS_FILTER_TYPE_YOUNG:
   246			matched = damon_folio_young(folio);
   247			if (matched)
   248				damon_folio_mkold(folio);
   249			break;
   250	#if defined(CONFIG_PGTABLE_HAS_HUGE_LEAVES)
   251		case DAMOS_FILTER_TYPE_HUGEPAGE:
   252			folio_sz = folio_size(folio);
   253			matched = filter->folio_size.min <= folio_sz && folio_sz <= filter->folio_size.max;
   254			break;
   255	#endif
   256		default:
   257			break;
   258		}
   259	
   260		return matched == filter->matching;
   261	}
   262	

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