Re: [PATCH v5 3/4] mm: memcontrol: add interfaces for swap tier selection

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

Hi Youngjun,

kernel test robot noticed the following build errors:

[auto build test ERROR on 6381a729fa7dda43574d93ab9c61cec516dd885b]

url:    https://github.com/intel-lab-lkp/linux/commits/Youngjun-Park/mm-swap-introduce-swap-tier-infrastructure/20260327-203639
base:   6381a729fa7dda43574d93ab9c61cec516dd885b
patch link:    https://lore.kernel.org/r/20260325175453.2523280-4-youngjun.park%40lge.com
patch subject: [PATCH v5 3/4] mm: memcontrol: add interfaces for swap tier selection
config: hexagon-randconfig-002-20260329 (https://download.01.org/0day-ci/archive/20260329/202603291945.9q4pyvON-lkp@intel.com/config)
compiler: clang version 23.0.0git (https://github.com/llvm/llvm-project 054e11d1a17e5ba88bb1a8ef32fad3346e80b186)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260329/202603291945.9q4pyvON-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/202603291945.9q4pyvON-lkp@intel.com/

All errors (new ones prefixed by >>):

   mm/swap_tier.c:141:10: warning: format specifies type 'long' but the argument has type '__ptrdiff_t' (aka 'int') [-Wformat]
     139 |                 len += sysfs_emit_at(buf, len, "%-16s %-5ld %-11d %-11d\n",
         |                                                       ~~~~~
         |                                                       %-5td
     140 |                                      tier->name,
     141 |                                      TIER_IDX(tier),
         |                                      ^~~~~~~~~~~~~~
   mm/swap_tier.c:33:24: note: expanded from macro 'TIER_IDX'
      33 | #define TIER_IDX(tier)  ((tier) - swap_tiers)
         |                         ^~~~~~~~~~~~~~~~~~~~~
>> mm/swap_tier.c:342:8: error: incomplete definition of type 'struct mem_cgroup'
     342 |                 child->tier_mask |= mask;
         |                 ~~~~~^
   include/linux/mm_types.h:36:8: note: forward declaration of 'struct mem_cgroup'
      36 | struct mem_cgroup;
         |        ^
   mm/swap_tier.c:343:8: error: incomplete definition of type 'struct mem_cgroup'
     343 |                 child->tier_effective_mask |= mask;
         |                 ~~~~~^
   include/linux/mm_types.h:36:8: note: forward declaration of 'struct mem_cgroup'
      36 | struct mem_cgroup;
         |        ^
   mm/swap_tier.c:420:20: error: incomplete definition of type 'struct mem_cgroup'
     420 |                 = parent ? parent->tier_effective_mask : TIER_ALL_MASK;
         |                            ~~~~~~^
   include/linux/mm_types.h:36:8: note: forward declaration of 'struct mem_cgroup'
      36 | struct mem_cgroup;
         |        ^
   mm/swap_tier.c:422:7: error: incomplete definition of type 'struct mem_cgroup'
     422 |         memcg->tier_effective_mask
         |         ~~~~~^
   include/linux/mm_types.h:36:8: note: forward declaration of 'struct mem_cgroup'
      36 | struct mem_cgroup;
         |        ^
   mm/swap_tier.c:423:27: error: incomplete definition of type 'struct mem_cgroup'
     423 |                 = effective_mask & memcg->tier_mask;
         |                                    ~~~~~^
   include/linux/mm_types.h:36:8: note: forward declaration of 'struct mem_cgroup'
      36 | struct mem_cgroup;
         |        ^
   1 warning and 5 errors generated.


vim +342 mm/swap_tier.c

   330	
   331	/*
   332	 * When a tier is removed, set its bit in every memcg's tier_mask and
   333	 * tier_effective_mask. This prevents stale tier indices from being
   334	 * silently filtered out if the same index is reused later.
   335	 */
   336	static void swap_tier_memcg_propagate(int mask)
   337	{
   338		struct mem_cgroup *child;
   339	
   340		rcu_read_lock();
   341		for_each_mem_cgroup_tree(child, root_mem_cgroup) {
 > 342			child->tier_mask |= mask;
   343			child->tier_effective_mask |= mask;
   344		}
   345		rcu_read_unlock();
   346	}
   347	

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