Re: [PATCH] smaps: fill missing fields for vma(VM_HUGETLB)

David Rientjes
2015-08-06T02:18:48Z

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On Tue, 4 Aug 2015, Jörn Engel wrote:

> > From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
> > Subject: [PATCH] smaps: fill missing fields for vma(VM_HUGETLB)
> >
> > Currently smaps reports many zero fields for vma(VM_HUGETLB), which is
> > inconvenient when we want to know per-task or per-vma base hugetlb usage.
> > This patch enables these fields by introducing smaps_hugetlb_range().
> >
> > before patch:
> >
> > Size: 20480 kB
> > Rss: 0 kB
> > Pss: 0 kB
> > Shared_Clean: 0 kB
> > Shared_Dirty: 0 kB
> > Private_Clean: 0 kB
> > Private_Dirty: 0 kB
> > Referenced: 0 kB
> > Anonymous: 0 kB
> > AnonHugePages: 0 kB
> > Swap: 0 kB
> > KernelPageSize: 2048 kB
> > MMUPageSize: 2048 kB
> > Locked: 0 kB
> > VmFlags: rd wr mr mw me de ht
> >
> > after patch:
> >
> > Size: 20480 kB
> > Rss: 18432 kB
> > Pss: 18432 kB
> > Shared_Clean: 0 kB
> > Shared_Dirty: 0 kB
> > Private_Clean: 0 kB
> > Private_Dirty: 18432 kB
> > Referenced: 18432 kB
> > Anonymous: 18432 kB
> > AnonHugePages: 0 kB
> > Swap: 0 kB
> > KernelPageSize: 2048 kB
> > MMUPageSize: 2048 kB
> > Locked: 0 kB
> > VmFlags: rd wr mr mw me de ht
>
> Nice!
>

Hmm, wouldn't this be confusing since VmRSS in /proc/pid/status doesn't
match the rss shown in smaps, since hugetlb mappings aren't accounted in
get_mm_rss()?

Not sure this is a good idea, I think consistency amongst rss values would
be more important.