Subject: Re: [PATCH] hugetlb: /proc/meminfo shows data for all sizes of
 hugepages
From: Dave Hansen <dave@linux.vnet.ibm.com>
To: Petr Holasek <pholasek@redhat.com>
Cc: linux-kernel@vger.kernel.org, emunson@mgebm.net, anton@redhat.com,
        Andi Kleen <ak@linux.intel.com>,
        Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
        Mel Gorman <mel@csn.ul.ie>, Andrew Morton <akpm@linux-foundation.org>,
        Wu Fengguang <fengguang.wu@intel.com>, linux-mm@kvack.org
In-Reply-To: <1299503155-6210-1-git-send-email-pholasek@redhat.com>
References: <1299503155-6210-1-git-send-email-pholasek@redhat.com>
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Date: Mon, 07 Mar 2011 11:46:54 -0800
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On Mon, 2011-03-07 at 14:05 +0100, Petr Holasek wrote:
> +       for_each_hstate(h)
> +               seq_printf(m,
> +                               "HugePages_Total:   %5lu\n"
> +                               "HugePages_Free:    %5lu\n"
> +                               "HugePages_Rsvd:    %5lu\n"
> +                               "HugePages_Surp:    %5lu\n"
> +                               "Hugepagesize:   %8lu kB\n",
> +                               h->nr_huge_pages,
> +                               h->free_huge_pages,
> +                               h->resv_huge_pages,
> +                               h->surplus_huge_pages,
> +                               1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
>  }

It sounds like now we'll get a meminfo that looks like:

...
AnonHugePages:    491520 kB
HugePages_Total:       5
HugePages_Free:        2
HugePages_Rsvd:        3
HugePages_Surp:        1
Hugepagesize:       2048 kB
HugePages_Total:       2
HugePages_Free:        1
HugePages_Rsvd:        1
HugePages_Surp:        1
Hugepagesize:    1048576 kB
DirectMap4k:       12160 kB
DirectMap2M:     2082816 kB
DirectMap1G:     2097152 kB

At best, that's a bit confusing.  There aren't any other entries in
meminfo that occur more than once.  Plus, this information is available
in the sysfs interface.  Why isn't that sufficient?

Could we do something where we keep the default hpage_size looking like
it does now, but append the size explicitly for the new entries?

HugePages_Total(1G):       2
HugePages_Free(1G):        1
HugePages_Rsvd(1G):        1
HugePages_Surp(1G):        1

-- Dave

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