Re: [PATCH] mm: show total hugetlb memory consumption in /proc/meminfo

Johannes Weiner
2017-11-14T21:07:17Z

On Tue, Nov 14, 2017 at 12:50:26PM +0000, Roman Gushchin wrote:
> Currently we display some hugepage statistics (total, free, etc)
> in /proc/meminfo, but only for default hugepage size (e.g. 2Mb).
>
> If hugepages of different sizes are used (like 2Mb and 1Gb on x86-64),
> /proc/meminfo output can be confusing, as non-default sized hugepages
> are not reflected at all, and there are no signs that they are
> existing and consuming system memory.
>
> To solve this problem, let's display the total amount of memory,
> consumed by hugetlb pages of all sized (both free and used).
> Let's call it "Hugetlb", and display size in kB to match generic
> /proc/meminfo style.
>
> For example, (1024 2Mb pages and 2 1Gb pages are pre-allocated):
> $ cat /proc/meminfo
> MemTotal: 8168984 kB
> MemFree: 3789276 kB
> <...>
> CmaFree: 0 kB
> HugePages_Total: 1024
> HugePages_Free: 1024
> HugePages_Rsvd: 0
> HugePages_Surp: 0
> Hugepagesize: 2048 kB
> Hugetlb: 4194304 kB
> DirectMap4k: 32632 kB
> DirectMap2M: 4161536 kB
> DirectMap1G: 6291456 kB
>
> Signed-off-by: Roman Gushchin <guro@fb.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Mike Kravetz <mike.kravetz@oracle.com>
> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
> Cc: Andrea Arcangeli <aarcange@redhat.com>
> Cc: Dave Hansen <dave.hansen@intel.com>
> Cc: kernel-team@fb.com
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org

Acked-by: Johannes Weiner <hannes@cmpxchg.org>