Re: [PATCH] memcg, kmem: mark cancel_charge() inline

[Muchun Song <songmuchun@bytedance.com>]

On Fri, Oct 22, 2021 at 3:05 PM Arnd Bergmann <arnd@kernel.org> wrote:
>
> From: Arnd Bergmann <arnd@arndb.de>
>
> cancel_charge() is no longer called for CONFIG_MEMCG_KMEM on NOMMU
> targets, which causes a compiletime warning:
>
> mm/memcontrol.c:2774:13: error: unused function 'cancel_charge' [-Werror,-Wunused-function]
>
> Remove the now-incorrect #ifdef and just mark the function
> 'inline' like the other related helpers. This is simpler
> and means we no longer have to match the #ifdef with the
> caller.
>
> Fixes: 5f3345c17079 ("memcg, kmem: further deprecate kmem.limit_in_bytes")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Thanks. I guess this should be squashed into the commit 5f3345c17079
("memcg, kmem: further deprecate kmem.limit_in_bytes").

Reviewed-by: Muchun Song <songmuchun@bytedance.com>

> ---
> The 5f3345c17079 commit is in -mm, so the commit ID is not
> stable. Feel free to just fold this into the other patch, or
> take out that reference
> ---
>  mm/memcontrol.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 6538595994d2..9edccfeac804 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -2770,8 +2770,7 @@ static inline int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
>         return try_charge_memcg(memcg, gfp_mask, nr_pages);
>  }
>
> -#if defined(CONFIG_MEMCG_KMEM) || defined(CONFIG_MMU)
> -static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)
> +static inline void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)
>  {
>         if (mem_cgroup_is_root(memcg))
>                 return;
> @@ -2780,7 +2779,6 @@ static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)
>         if (do_memsw_account())
>                 page_counter_uncharge(&memcg->memsw, nr_pages);
>  }
> -#endif
>
>  static void commit_charge(struct folio *folio, struct mem_cgroup *memcg)
>  {
> --
> 2.29.2
>