Why dose RSS have more bytes than runtime.memstats?

2A5A2E79-E410-48B3-AF95-9FA4BC717301
output of runtime.Memstats
AD34CE7F-D6D4-4D65-A23B-22DE154C74B0
output of ps aux

I have two questions:

  1. what is the real memory used in the system according to the runtime.MemStats?
    for this question, my point is Sys - HeapReleased = 65M
  2. If the first question is right, the size of RSS(101M) > 65M. Why?