on one box, systemctl show get an incorrect value for unit memory usage:
$ systemctl show crond | grep MemoryCurrent
MemoryCurrent=18446744073709551615
18446744073709551615 == UINT64_MAX, this must be incorrect.
but another box shows correct memory usage:
$ systemctl show crond | grep MemoryCurrent
MemoryCurrent=1490944
both machines use CentOS7 and preshipped systemd 219:
# systemctl --version
systemd 219
+PAM +AUDIT +SELINUX +IMA -APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 -SECCOMP +BLKID +ELFUTILS +KMOD +IDN
and have set MemoryAccounting=no.
how to make systemctl/systemd behavior correctly?
see also in the related mailing list thread and another question.
