On Thu, Oct 26, 2017 at 9:00 PM, Du, Fan <[email protected]> wrote: > > >>-----Original Message----- >>From: [email protected] >>[mailto:[email protected]] On Behalf Of Dave Hansen >>Sent: Thursday, October 26, 2017 10:51 PM >>To: Michal Hocko <[email protected]> >>Cc: Du, Fan <[email protected]>; [email protected]; [email protected]; >>Williams, Dan J <[email protected]>; [email protected]; >>[email protected] >>Subject: Re: [PATCH 2/2] Add /proc/PID/{smaps, numa_maps} support for DAX >> >>On 10/26/2017 07:31 AM, Michal Hocko wrote: >>> On Thu 26-10-17 07:24:14, Dave Hansen wrote: >>>> Actually, I don't remember whether it was tooling or just confused >>>> humans. I *think* Dan was trying to write test cases for huge page DAX >>>> support and couldn't figure out whether or not it was using large pages. >>> >>> That sounds like a very weak justification to adding new stuff to smaps >>> to be honest. >> >>Yep, agreed. It can't go in _just_ for DAX, and Fan and the other DAX >>folks need to elaborate on their needs here. > > If user creates device DAX /dev/dax with some capacity like 512G, mmap it and > Use it will, or touched 128G. To my best knowledge at this part, there is no > statistics reported how much memory behind DAX actually used. > > This is the problem our customer is facing right now.
I'm not sure I understand, DAX is statically allocated. There's no private memory taken from the page allocator to back device-dax mappings. Unless you are trying to determine memory usage of page tables?
