Re: [PATCH v4 3/4] mm/page_owner: Print memcg information

[Michal Hocko]

On Wed 02-02-22 15:30:35, Waiman Long wrote:
[...]
> +#ifdef CONFIG_MEMCG
> +	unsigned long memcg_data;
> +	struct mem_cgroup *memcg;
> +	bool online;
> +	char name[80];
> +
> +	rcu_read_lock();
> +	memcg_data = READ_ONCE(page->memcg_data);
> +	if (!memcg_data)
> +		goto out_unlock;
> +
> +	if (memcg_data & MEMCG_DATA_OBJCGS)
> +		ret += scnprintf(kbuf + ret, count - ret,
> +				"Slab cache page\n");
> +
> +	memcg = page_memcg_check(page);
> +	if (!memcg)
> +		goto out_unlock;
> +
> +	online = (memcg->css.flags & CSS_ONLINE);
> +	cgroup_name(memcg->css.cgroup, name, sizeof(name));

Is there any specific reason to use another buffer allocated on the
stack? Also 80B seems too short to cover NAME_MAX.

Nothing else jumped at me.
-- 
Michal Hocko
SUSE Labs