Re: [PATCH v2 1/2] mm, memcg: rename mem_cgroup_out_of_memory()

From: Michal Hocko <mhocko@kernel.org>
To: Yafang Shao <laoar.shao@gmail.com>
Cc: akpm@linux-foundation.org, shakeelb@google.com,
	hannes@cmpxchg.org, guro@fb.com, gthelen@google.com,
	linux-mm@kvack.org
Subject: Re: [PATCH v2 1/2] mm, memcg: rename mem_cgroup_out_of_memory()
Date: Mon, 4 May 2020 09:59:02 +0200	[thread overview]
Message-ID: <20200504075902.GH22838@dhcp22.suse.cz> (raw)
In-Reply-To: <20200504042621.10334-2-laoar.shao@gmail.com>

On Mon 04-05-20 00:26:20, Yafang Shao wrote:
> Rename mem_cgroup_out_of_memory() to mem_cgroup_oom_kill() to indicate
> that this function is used to try to kill a process.
> With this change it will cooperate better with the oom events.
> 	function		memcg event
> 	mem_cgroup_oom()	oom
> 	mem_cgroup_oom_kill()	oom_kill
> 
> Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
> Reviewed-by: Shakeel Butt <shakeelb@google.com>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Roman Gushchin <guro@fb.com>
> Cc: Greg Thelen <gthelen@google.com>

Well, I do not have a strong opinion on this. I believe the idea behind
the naming was that this is a memcg counterpart for out_of_memory.
So to be honest I do not consider this an improvement.

> ---
>  mm/memcontrol.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 5beea03dd58a..985edce98491 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -1570,7 +1570,7 @@ unsigned long mem_cgroup_size(struct mem_cgroup *memcg)
>  	return page_counter_read(&memcg->memory);
>  }
>  
> -static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
> +static bool mem_cgroup_oom_kill(struct mem_cgroup *memcg, gfp_t gfp_mask,
>  				     int order)
>  {
>  	struct oom_control oc = {
> @@ -1799,7 +1799,7 @@ static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int
>  	 * relying on the oom victim to make a forward progress and we can
>  	 * invoke the oom killer here.
>  	 *
> -	 * Please note that mem_cgroup_out_of_memory might fail to find a
> +	 * Please note that mem_cgroup_oom_kill might fail to find a
>  	 * victim and then we have to bail out from the charge path.
>  	 */
>  	if (memcg->oom_kill_disable) {
> @@ -1821,7 +1821,7 @@ static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int
>  		mem_cgroup_oom_notify(memcg);
>  
>  	mem_cgroup_unmark_under_oom(memcg);
> -	if (mem_cgroup_out_of_memory(memcg, mask, order))
> +	if (mem_cgroup_oom_kill(memcg, mask, order))
>  		ret = OOM_SUCCESS;
>  	else
>  		ret = OOM_FAILED;
> @@ -1879,7 +1879,7 @@ bool mem_cgroup_oom_synchronize(bool handle)
>  	if (locked && !memcg->oom_kill_disable) {
>  		mem_cgroup_unmark_under_oom(memcg);
>  		finish_wait(&memcg_oom_waitq, &owait.wait);
> -		mem_cgroup_out_of_memory(memcg, current->memcg_oom_gfp_mask,
> +		mem_cgroup_oom_kill(memcg, current->memcg_oom_gfp_mask,
>  					 current->memcg_oom_order);
>  	} else {
>  		schedule();
> @@ -6102,7 +6102,7 @@ static ssize_t memory_max_write(struct kernfs_open_file *of,
>  		}
>  
>  		memcg_memory_event(memcg, MEMCG_OOM);
> -		if (!mem_cgroup_out_of_memory(memcg, GFP_KERNEL, 0))
> +		if (!mem_cgroup_oom_kill(memcg, GFP_KERNEL, 0))
>  			break;
>  	}
>  
> -- 
> 2.18.2

-- 
Michal Hocko
SUSE Labs