2017-11-14 23:07:53

by Johannes Weiner

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

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 <[email protected]>
> Cc: Andrew Morton <[email protected]>
> Cc: Michal Hocko <[email protected]>
> Cc: Johannes Weiner <[email protected]>
> Cc: Mike Kravetz <[email protected]>
> Cc: "Aneesh Kumar K.V" <[email protected]>
> Cc: Andrea Arcangeli <[email protected]>
> Cc: Dave Hansen <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]

Acked-by: Johannes Weiner <[email protected]>

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