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Date:   Sun, 28 Aug 2022 21:42:00 +0300
From:   Alexey Dobriyan <adobriyan@gmail.com>
To:     xu xin <cgel.zte@gmail.com>
Cc:     akpm@linux-foundation.org, corbet@lwn.net, bagasdotme@gmail.com,
        willy@infradead.org, hughd@google.com,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-mm@kvack.org, xu xin <xu.xin16@zte.com.cn>,
        Xiaokai Ran <ran.xiaokai@zte.com.cn>,
        Yang Yang <yang.yang29@zte.com.cn>
Subject: Re: [PATCH v4 1/2] ksm: count allocated ksm rmap_items for each
 process
Message-ID: <Ywu2+OiL9oqohr1v@localhost.localdomain>
References: <20220824124512.223103-1-xu.xin16@zte.com.cn>
 <20220824124615.223158-1-xu.xin16@zte.com.cn>
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On Wed, Aug 24, 2022 at 12:46:15PM +0000, xu xin wrote:
> +static int proc_pid_ksm_rmp_items(struct seq_file *m, struct pid_namespace *ns,
> +				struct pid *pid, struct task_struct *task)
> +{
> +	struct mm_struct *mm;
> +
> +	mm = get_task_mm(task);
> +	if (mm) {
> +		seq_printf(m, "%lu\n", mm->ksm_rmp_items);
> +		mmput(mm);
> +	}
> +
> +	return 0;
> +}
>  #endif /* CONFIG_KSM */
>  
>  #ifdef CONFIG_STACKLEAK_METRICS
> @@ -3334,6 +3347,7 @@ static const struct pid_entry tgid_base_stuff[] = {
>  #endif
>  #ifdef CONFIG_KSM
>  	ONE("ksm_merging_pages",  S_IRUSR, proc_pid_ksm_merging_pages),
> +	ONE("ksm_rmp_items",  S_IRUSR, proc_pid_ksm_rmp_items),
>  #endif

Another tiny /proc/$pid/ file?

Guys, this problem with "find /proc" instantiating megabytes is not
getting better only worse.

How did KSM didn't get its own /proc/*/ksm file with many values?

Maybe add /proc/*/ksm and start filling it with stuff leaving
/proc/*/ksm_merging_pages alone?