Comment 23 for bug 1729878

So I did this on 4.4 on ppc64le with 32GB RAM and 96GB Swap:
ubuntu@entei:~$ free -lm
              total used free shared buff/cache available
Mem: 32565 656 30603 2 1304 30503
Low: 32565 1961 30603
High: 0 0 0
Swap: 97695 342 97353

And this time OOMKiller was not hit.

ubuntu@entei:~$ ./memory_stress_ng
Total memory is 32 GiB
Constant run time is 300 seconds per stressor
Variable run time is 620 seconds per stressor
Estimated total run time is 20 minutes

Running stress-ng stack stressor for 300 seconds....
stress-ng: info: [15395] dispatching hogs: 128 stack
stress-ng: info: [15395] cache allocate: using built-in defaults as unable to determine cache details
stress-ng: info: [15395] cache allocate: default cache size: 2048K
stress-ng: info: [15395] successful run completed in 317.89s (5 mins, 17.89 secs)
return_code is 0
Running stress-ng numa stressor for 300 seconds....
stress-ng: info: [15663] dispatching hogs: 128 numa
stress-ng: info: [15663] cache allocate: using built-in defaults as unable to determine cache details
stress-ng: info: [15663] cache allocate: default cache size: 2048K
stress-ng: info: [15664] stress-ng-numa: system has 1 of a maximum 256 memory NUMA nodes
stress-ng: info: [15663] successful run completed in 300.08s (5 mins, 0.08 secs)
return_code is 0
Running stress-ng brk stressor for 620 seconds....
stress-ng: info: [15800] dispatching hogs: 128 brk
stress-ng: info: [15800] cache allocate: using built-in defaults as unable to determine cache details
stress-ng: info: [15800] cache allocate: default cache size: 2048K
stress-ng: info: [15800] successful run completed in 666.16s (11 mins, 6.16 secs)
return_code is 0
*******************************************************************
** stress-ng memory test passed!
*******************************************************************

The only message that appeared in dmesg during this test run is one warning: (I cleared the ring buffer with dmesg -C before running the test).
ubuntu@entei:~$ dmesg
[ 7390.968438] stress-ng[15584]: bad frame in setup_rt_frame: 00003fffdd0e1040 nip

And from looking at vmstat, this is the lowest and highest consumption observed:
 0 0 340 30582 14 1299 0 0 3 385 27 25 3 3 75 19 0
 0 260 58068 196 12 1323 2 76 2571 78490 3295 5493 0 0 25 74 0

So at the least, only 340MB swap consumed and a full 30GB ram free, and at the most, 58GB swap consumed and only 196MB free.

So there DOES seem to be a limit to what these tests are consuming.