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Date:   Thu, 4 Feb 2021 14:30:38 +0100
From:   Michal Hocko <mhocko@suse.com>
To:     Johannes Weiner <hannes@cmpxchg.org>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Tejun Heo <tj@kernel.org>, Roman Gushchin <guro@fb.com>,
        linux-mm@kvack.org, cgroups@vger.kernel.org,
        linux-kernel@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH 3/7] mm: memcontrol: privatize memcg_page_state query
 functions
Message-ID: <YBv2/hAXno4JDc8s@dhcp22.suse.cz>
References: <20210202184746.119084-1-hannes@cmpxchg.org>
 <20210202184746.119084-4-hannes@cmpxchg.org>
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On Tue 02-02-21 13:47:42, Johannes Weiner wrote:
> There are no users outside of the memory controller itself. The rest
> of the kernel cares either about node or lruvec stats.
> 
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>

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

> ---
>  include/linux/memcontrol.h | 44 --------------------------------------
>  mm/memcontrol.c            | 32 +++++++++++++++++++++++++++
>  2 files changed, 32 insertions(+), 44 deletions(-)
> 
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index c7f387a6233e..20ecdfae3289 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -867,39 +867,6 @@ struct mem_cgroup *lock_page_memcg(struct page *page);
>  void __unlock_page_memcg(struct mem_cgroup *memcg);
>  void unlock_page_memcg(struct page *page);
>  
> -/*
> - * idx can be of type enum memcg_stat_item or node_stat_item.
> - * Keep in sync with memcg_exact_page_state().
> - */
> -static inline unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx)
> -{
> -	long x = atomic_long_read(&memcg->vmstats[idx]);
> -#ifdef CONFIG_SMP
> -	if (x < 0)
> -		x = 0;
> -#endif
> -	return x;
> -}
> -
> -/*
> - * idx can be of type enum memcg_stat_item or node_stat_item.
> - * Keep in sync with memcg_exact_page_state().
> - */
> -static inline unsigned long memcg_page_state_local(struct mem_cgroup *memcg,
> -						   int idx)
> -{
> -	long x = 0;
> -	int cpu;
> -
> -	for_each_possible_cpu(cpu)
> -		x += per_cpu(memcg->vmstats_local->stat[idx], cpu);
> -#ifdef CONFIG_SMP
> -	if (x < 0)
> -		x = 0;
> -#endif
> -	return x;
> -}
> -
>  void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val);
>  
>  /* idx can be of type enum memcg_stat_item or node_stat_item */
> @@ -1337,17 +1304,6 @@ static inline void mem_cgroup_print_oom_group(struct mem_cgroup *memcg)
>  {
>  }
>  
> -static inline unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx)
> -{
> -	return 0;
> -}
> -
> -static inline unsigned long memcg_page_state_local(struct mem_cgroup *memcg,
> -						   int idx)
> -{
> -	return 0;
> -}
> -
>  static inline void __mod_memcg_state(struct mem_cgroup *memcg,
>  				     int idx,
>  				     int nr)
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 7e05a4ebf80f..2f97cb4cef6d 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -789,6 +789,38 @@ void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val)
>  	__this_cpu_write(memcg->vmstats_percpu->stat[idx], x);
>  }
>  
> +/*
> + * idx can be of type enum memcg_stat_item or node_stat_item.
> + * Keep in sync with memcg_exact_page_state().
> + */
> +static unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx)
> +{
> +	long x = atomic_long_read(&memcg->vmstats[idx]);
> +#ifdef CONFIG_SMP
> +	if (x < 0)
> +		x = 0;
> +#endif
> +	return x;
> +}
> +
> +/*
> + * idx can be of type enum memcg_stat_item or node_stat_item.
> + * Keep in sync with memcg_exact_page_state().
> + */
> +static unsigned long memcg_page_state_local(struct mem_cgroup *memcg, int idx)
> +{
> +	long x = 0;
> +	int cpu;
> +
> +	for_each_possible_cpu(cpu)
> +		x += per_cpu(memcg->vmstats_local->stat[idx], cpu);
> +#ifdef CONFIG_SMP
> +	if (x < 0)
> +		x = 0;
> +#endif
> +	return x;
> +}
> +
>  static struct mem_cgroup_per_node *
>  parent_nodeinfo(struct mem_cgroup_per_node *pn, int nid)
>  {
> -- 
> 2.30.0
> 

-- 
Michal Hocko
SUSE Labs