Re: [akpm-mm:mm-unstable 27/106] mm/page_io.c:220:3: error: call to undeclared function 'count_objcg_events'; ISO C99 and later do not support implicit function declarations

[Barry Song <21cnbao@gmail.com>]

On Thu, Nov 7, 2024 at 2:24 AM kernel test robot <lkp@intel.com> wrote:
>
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-unstable
> head:   7994b7ea6ac880efd0c38fedfbffd5ab8b1b7b2b
> commit: c10966f19a878a66206327ebe3b85500f59f47e2 [27/106] mm: count zeromap read and set for swapout and swapin
> config: x86_64-kexec (https://download.01.org/0day-ci/archive/20241106/202411062130.JXvq8Cjt-lkp@intel.com/config)
> compiler: clang version 19.1.3 (https://github.com/llvm/llvm-project ab51eccf88f5321e7c60591c5546b254b6afab99)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241106/202411062130.JXvq8Cjt-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/202411062130.JXvq8Cjt-lkp@intel.com/
>
> Note: the akpm-mm/mm-unstable HEAD 7994b7ea6ac880efd0c38fedfbffd5ab8b1b7b2b builds fine.
>       It only hurts bisectability.
>
> All errors (new ones prefixed by >>):
>
>    In file included from mm/page_io.c:14:
>    In file included from include/linux/mm.h:2213:
>    include/linux/vmstat.h:504:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
>      504 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
>          |                            ~~~~~~~~~~~~~~~~~~~~~ ^
>      505 |                            item];
>          |                            ~~~~
>    include/linux/vmstat.h:511:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
>      511 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
>          |                            ~~~~~~~~~~~~~~~~~~~~~ ^
>      512 |                            NR_VM_NUMA_EVENT_ITEMS +
>          |                            ~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/vmstat.h:518:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
>      518 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
>          |                               ~~~~~~~~~~~ ^ ~~~
>    include/linux/vmstat.h:524:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
>      524 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
>          |                            ~~~~~~~~~~~~~~~~~~~~~ ^
>      525 |                            NR_VM_NUMA_EVENT_ITEMS +
>          |                            ~~~~~~~~~~~~~~~~~~~~~~
> >> mm/page_io.c:220:3: error: call to undeclared function 'count_objcg_events'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
>      220 |                 count_objcg_events(objcg, SWPOUT_ZERO, nr_pages);
>          |                 ^
>    mm/page_io.c:220:3: note: did you mean 'count_objcg_event'?
>    include/linux/memcontrol.h:1763:20: note: 'count_objcg_event' declared here
>     1763 | static inline void count_objcg_event(struct obj_cgroup *objcg,
>          |                    ^
>    mm/page_io.c:532:3: error: call to undeclared function 'count_objcg_events'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
>      532 |                 count_objcg_events(objcg, SWPIN_ZERO, nr_pages);
>          |                 ^
>    4 warnings and 2 errors generated.

Is it because Kanchana's "mm: change count_objcg_event() to count_objcg_events()
for batch event updates" doesn't exist?
Hi Andrew, is it possible to take this one also into mm-hotfixes-unstable?

commit 206ad49987b4670e01a3a0fd5673a823a94499d5
Author: Kanchana P Sridhar <kanchana.p.sridhar@intel.com>
Date:   Mon Sep 30 22:32:19 2024 -0700
    mm: change count_objcg_event() to count_objcg_events() for batch
event updates
    With the introduction of zswap_store() swapping out large folios, we need
    to efficiently update the objcg's memcg events once per successfully
    stored folio.  For instance, the 'ZSWPOUT' event needs to be incremented
    by folio_nr_pages().

    To facilitate this, the existing count_objcg_event() API is modified to be
    count_objcg_events() that additionally accepts a count parameter.  The
    only existing calls to count_objcg_event() are in zswap.c - these have
    been modified to call count_objcg_events() with a count of 1.

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 15c2716f9aa3..524006313b0d 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1764,8 +1764,9 @@ static inline int memcg_kmem_id(struct mem_cgroup *memcg)

 struct mem_cgroup *mem_cgroup_from_slab_obj(void *p);

-static inline void count_objcg_event(struct obj_cgroup *objcg,
-                                    enum vm_event_item idx)
+static inline void count_objcg_events(struct obj_cgroup *objcg,
+                                     enum vm_event_item idx,
+                                     unsigned long count)
 {

>
>
> vim +/count_objcg_events +220 mm/page_io.c
>
>    204
>    205  static void swap_zeromap_folio_set(struct folio *folio)
>    206  {
>    207          struct obj_cgroup *objcg = get_obj_cgroup_from_folio(folio);
>    208          struct swap_info_struct *sis = swp_swap_info(folio->swap);
>    209          int nr_pages = folio_nr_pages(folio);
>    210          swp_entry_t entry;
>    211          unsigned int i;
>    212
>    213          for (i = 0; i < folio_nr_pages(folio); i++) {
>    214                  entry = page_swap_entry(folio_page(folio, i));
>    215                  set_bit(swp_offset(entry), sis->zeromap);
>    216          }
>    217
>    218          count_vm_events(SWPOUT_ZERO, nr_pages);
>    219          if (objcg) {
>  > 220                  count_objcg_events(objcg, SWPOUT_ZERO, nr_pages);
>    221                  obj_cgroup_put(objcg);
>    222          }
>    223  }
>    224
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki
>

Thanks
barry