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Date:   Fri, 29 May 2020 10:19:09 +0200
From:   Michal Hocko <mhocko@kernel.org>
To:     Arnd Bergmann <arnd@arndb.de>
Cc:     Johannes Weiner <hannes@cmpxchg.org>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Alex Shi <alex.shi@linux.alibaba.com>,
        Hugh Dickins <hughd@google.com>,
        "Kirill A. Shutemov" <kirill@shutemov.name>,
        Roman Gushchin <guro@fb.com>,
        Shakeel Butt <shakeelb@google.com>,
        Balbir Singh <bsingharora@gmail.com>,
        Chris Down <chris@chrisdown.name>,
        Yafang Shao <laoar.shao@gmail.com>, Tejun Heo <tj@kernel.org>,
        cgroups@vger.kernel.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: memcontrol: fix an unused-function warning
Message-ID: <20200529081909.GG4406@dhcp22.suse.cz>
References: <20200528095640.151454-1-arnd@arndb.de>
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On Thu 28-05-20 11:56:26, Arnd Bergmann wrote:
> On NOMMU kernels without CONFIG_MEMCG_KMEM, we now get a harmless
> warning about an unused function:
> 
> mm/memcontrol.c:2595:13: error: unused function 'cancel_charge' [-Werror,-Wunused-function]
> 
> Hide this function in a matching #ifdef.
> 
> Fixes: 5bd144bf764c ("mm: memcontrol: drop unused try/commit/cancel charge API")

This is a linux-next sha1 which is not valid anymore. I would just drop
the tag.

> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Acked-by: Michal Hocko <mhocko@suse.com>

Thanks!
> ---
>  mm/memcontrol.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index f14da7a7348b..7bfca0abb8e1 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -2592,6 +2592,7 @@ static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
>  	return 0;
>  }
>  
> +#if defined(CONFIG_MEMCG_KMEM) || defined(CONFIG_MMU)
>  static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)
>  {
>  	if (mem_cgroup_is_root(memcg))
> @@ -2603,6 +2604,7 @@ static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)
>  
>  	css_put_many(&memcg->css, nr_pages);
>  }
> +#endif
>  
>  static void commit_charge(struct page *page, struct mem_cgroup *memcg)
>  {
> -- 
> 2.26.2
> 

-- 
Michal Hocko
SUSE Labs