Comment 16 for bug 1672297

Actually it's not the "top" of the output that's interesting. The snapshot #1 just shows where memory went initially on start-up (to loading images). That doesn't represent the ongoing growth problem though. You need to scroll down to later snapshots in the ms_print output to see where the growth is coming from, like snapshot 51:

 47 68,075,238,605 72,060,280 63,908,218 8,152,062 0
 48 70,175,452,080 73,101,400 64,835,851 8,265,549 0
 49 71,750,692,416 74,288,744 65,927,330 8,361,414 0
 50 72,800,335,769 75,355,616 66,877,167 8,478,449 0
 51 73,849,979,162 81,425,416 72,853,026 8,572,390 0
89.47% (72,853,026B) (heap allocation functions) malloc/new/new[], --alloc-fns, etc.
->19.72% (16,059,766B) 0x58BF577: g_malloc (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.5400.1)
| ->17.59% (14,320,777B) 0x58D70F4: g_slice_alloc (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.5400.1)
| | ->13.29% (10,825,417B) 0x58D7587: g_slice_alloc0 (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.5400.1)
| | | ->05.48% (4,459,320B) 0x564F7E4: g_type_create_instance (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5400.1)
| | | | ->04.96% (4,040,752B) 0x5630096: ??? (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5400.1)
| | | | | ->04.84% (3,937,672B) 0x6C05829: ??? (in /usr/lib/x86_64-linux-gnu/mutter/libmutter-clutter-1.so)
| | | | | | ->04.55% (3,708,152B) 0x5630CF5: ??? (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5400.1)
| | | | | | | ->02.97% (2,417,720B) 0x5631FBC: g_object_newv (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5400.1)
| | | | | | | | ->02.97% (2,417,720B) 0x6911B0C: ??? (in /usr/lib/libgjs.so.0.0.0)
| | | | | | | | ->02.97% (2,417,720B) 0xE0BBD5B: ??? (in /usr/lib/x86_64-linux-gnu/libmozjs-52.so.0.0.0)
| | | | | | | | ->02.97% (2,417,720B) 0xE0BBF87: ??? (in /usr/lib/x86_64-linux-gnu/libmozjs-52.so.0.0.0)
| | | | | | | | ->02.97% (2,417,720B) 0xDF51842: JS_CallFunctionValue(JSContext*, JS::Handle<JSObject*>, JS::Handle<JS::Value>, JS::HandleValueArray const&, JS::MutableHandle<JS::Value>) (in /usr/lib/x86_64-linux-gnu/libmozjs-52.so.0.0.0)
| | | | | | | | ->02.97% (2,417,720B) 0x692B2A4: gjs_call_function_value (in /usr/lib/libgjs.so.0.0.0)
| | | | | | | | ->02.97% (2,417,720B) 0x6910454: ??? (in /usr/lib/libgjs.so.0.0.0)

So you then need debug symbols for libraries like:
  /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5400.1
  /usr/lib/x86_64-linux-gnu/mutter/libmutter-clutter-1.so
  /usr/lib/libgjs.so.0.0.0
  /usr/lib/x86_64-linux-gnu/libmozjs-52.so.0.0.0

Which sounds like it's getting closer to the core of the problem.