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Date:   Tue, 7 Aug 2018 14:12:06 +0000
From:   Christopher Lameter <cl@linux.com>
To:     Dennis Zhou <dennisszhou@gmail.com>
cc:     Andrew Morton <akpm@linux-foundation.org>,
        Tejun Heo <tj@kernel.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Roman Gushchin <guro@fb.com>, kernel-team@fb.com,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] proc: add percpu populated pages count to meminfo
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On Mon, 6 Aug 2018, Dennis Zhou wrote:

> diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c
> index 2fb04846ed11..ddd5249692e9 100644
> --- a/fs/proc/meminfo.c
> +++ b/fs/proc/meminfo.c
> @@ -7,6 +7,7 @@
>  #include <linux/mman.h>
>  #include <linux/mmzone.h>
>  #include <linux/proc_fs.h>
> +#include <linux/percpu.h>
>  #include <linux/quicklist.h>
>  #include <linux/seq_file.h>
>  #include <linux/swap.h>
> @@ -121,6 +122,7 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
>  		   (unsigned long)VMALLOC_TOTAL >> 10);
>  	show_val_kb(m, "VmallocUsed:    ", 0ul);
>  	show_val_kb(m, "VmallocChunk:   ", 0ul);
> +	show_val_kb(m, "PercpuPopulated:", pcpu_nr_populated_pages());

Populated? Can we avoid this for simplicities sake: "Percpu"?

We do not count pages that are not present elsewhere either and those
counters do not have "populated" in them.

>  int pcpu_nr_empty_pop_pages;
>
> +/*
> + * The number of populated pages in use by the allocator, protected by
> + * pcpu_lock.  This number is kept per a unit per chunk (i.e. when a page gets
> + * allocated/deallocated, it is allocated/deallocated in all units of a chunk
> + * and increments/decrements this count by 1).
> + */
> +static int pcpu_nr_populated;

pcpu_nr_pages?