Re: [PATCH] mm: show stats for non-default hugepage sizes in /proc/meminfo

Roman Gushchin
2017-11-13T18:45:32Z

On Mon, Nov 13, 2017 at 10:30:10AM -0800, Mike Kravetz wrote:
> On 11/13/2017 10:17 AM, Dave Hansen wrote:
> > On 11/13/2017 10:11 AM, Roman Gushchin wrote:
> >> On Mon, Nov 13, 2017 at 09:06:32AM -0800, Dave Hansen wrote:
> >>> On 11/13/2017 08:03 AM, Roman Gushchin wrote:
> >>>> To solve this problem, let's display stats for all hugepage sizes.
> >>>> To provide the backward compatibility let's save the existing format
> >>>> for the default size, and add a prefix (e.g. 1G_) for non-default sizes.
> >>>
> >>> Is there something keeping you from using the sysfs version of this
> >>> information?
> >>
> >> Just answered the same question to Michal.
> >>
> >> In two words: it would be nice to have a high-level overview of
> >> memory usage in the system in /proc/meminfo.
> >
> > I don't think it's worth cluttering up meminfo for this, imnho.
>
> I tend to agree that it would be better not to add additional huge page
> sizes here. It may not seem too intrusive to (potentially) add one extra
> set of entries for GB huge pages on x86. However, other architectures
> such as powerpc or sparc have several several huge pages sizes that could
> potentially be added here as well. Although, in practice one does tend
> to use a single huge pages size. If you change the default huge page
> size, then those entries will be in /proc/meminfo.

I do agree that it might add some unnecessary verbosity if these sizes
are not used, but if they are, this information is super-useful.
So, might be a conditional printing will work here?

Or, at least, some total counter, e.g. how much memory is consumed
by hugetlb pages?

Thanks!