Re: [PATCHv3 1/2] proc: mm: export PTE sizes directly in smaps

[Dave Hansen]

On 10/26/2017 07:19 AM, Michal Hocko wrote:
>> Current vm_normal_page implementation doesn't pick up page with DEVMAP pfn.
>> The second patch fix this and export DAX mappings into counters introduced in the
>> first patch.
>>
>> IMO, the user care more about how much persistent memory they used, how about
>> a small tweak with smaps_account, and report the total mapping size into RSS/PSS,
>> which user are usually more familiar with?
> No! Rss and pss is already used by many tools to evaluate misbehaving
> tasks. If you start accounting the memory which is not bound to the
> process life time then you can break those usecases. This is the reason
> why hugetlb is not accounted to rss as well.

Yeah, folks (rightly) assume Rss is memory and eaten from MemTotal.  DAX
mappings do not use RAM.