Android : PSS (Proportional Set Size) Calculation

I am trying to figure out how the PSS is calculated is Android. I found one article that states the following. The 'proportional set size' (PSS) of a process is the count of pages

Solution 1:

Yes, that information is accurate, and that's exactly how it is calculated. (The LWN.net article is here; note that Matt Mackall who participates in that thread you link to developed that feature.)

PSS is in kilobytes, like all the other information you get in /proc/<pid>/smaps. Its unit follows from how it is calculated.

(How often is PSS value updated for a given process in /proc/pid/smaps has some pointers as to where and how PSS is calculated - disclaimer: I wrote the answer there. There are a few other posts on Unix & Linux that discuss PSS and related metrics.)