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Subject: Re: [PATCH V4 6/6] proc: show MADV_FREE pages info in smaps
To: Shaohua Li <shli@fb.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
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From: Dave Hansen <dave.hansen@intel.com>
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Date: Fri, 24 Feb 2017 09:08:30 -0800
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On 02/22/2017 10:50 AM, Shaohua Li wrote:
> @@ -770,6 +774,7 @@ static int show_smap(struct seq_file *m, void *v, int is_pid)
>  		   "Private_Dirty:  %8lu kB\n"
>  		   "Referenced:     %8lu kB\n"
>  		   "Anonymous:      %8lu kB\n"
> +		   "LazyFree:       %8lu kB\n"
>  		   "AnonHugePages:  %8lu kB\n"
>  		   "ShmemPmdMapped: %8lu kB\n"
>  		   "Shared_Hugetlb: %8lu kB\n"

I've been as guily of this in the past as anyone, but are we just going
to keep adding fields to smaps forever?  For the vast, vast, majority of
folks, this will simply waste the 21 bytes * nr_vmas that it costs us to
print "LazyFree:       0 kB\n" over and over.

Should we maybe start a habit of not printing an entry when it's "0 kB"?