new ltp memcg gripe bisects to b67bf49ce7aa ("post mm/munlock: delete FOLL_MLOCK and FOLL_POPULATE")

[Mike Galbraith]

Greetings,

$subject bisected in a kvm ala:

leap153:/usr/local/ltp # cat testme
export PATH=$PATH:`pwd`/testcases/bin
memcg_stat_test.sh
leap153:/usr/local/ltp # . ./testme

Usually leads to...
memcg_stat_test 3 TINFO: Test unevictable with MAP_LOCKED
memcg_stat_test 3 TINFO: Running memcg_process --mmap-lock1 -s 135168
memcg_stat_test 3 TINFO: Warming up pid: 3460
memcg_stat_test 3 TINFO: Process is still here after warm up: 3460
memcg_stat_test 3 TFAIL: unevictable is 122880, 135168 expected
...but may lead to...
memcg_stat_test 4 TINFO: Test unevictable with mlock
memcg_stat_test 4 TINFO: Running memcg_process --mmap-lock2 -s 135168
memcg_stat_test 4 TINFO: Warming up pid: 4271
memcg_stat_test 4 TINFO: Process is still here after warm up: 4271
memcg_stat_test 4 TFAIL: unevictable is 122880, 135168 expected
...or both.  A wee bit flaky.

I wanted to verify with a revert on top of 85c7000fda00, but while the
revert patch applied, the result didn't boot.  Config is full distro.

	-Mike