Re: [PATCH v5 2/2] mm: hugetlb: proc: add HugetlbPages field to /proc/PID/status

David Rientjes
2015-08-25T23:23:38Z

On Mon, 24 Aug 2015, Michal Hocko wrote:

> The current implementation makes me worry. Is the per hstate break down
> really needed? The implementation would be much more easier without it.
>

Yes, it's needed. It provides a complete picture of what statically
reserved hugepages are in use and we're not going to change the
implementation when it is needed to differentiate between variable hugetlb
page sizes that risk breaking existing userspace parsers.

> If you have 99% of hugetlb pages then your load is rather specific and I
> would argue that /proc/<pid>/smaps (after patch 1) is a much better way to
> get what you want.
>

Some distributions change the permissions of smaps, as already stated, for
pretty clear security reasons since it can be used to defeat existing
protection. There's no reason why hugetlb page usage should not be
exported in the same manner and location as memory usage.

Sheesh.