hg: jdk/submit: 8239785: Cgroups: Incorrect detection logic on old systems in hotspot

[sgehwolf at redhat.com]

Changeset: 4fe87d390f80
Author:    sgehwolf
Date:      2020-02-25 12:17 +0100
URL:       https://hg.openjdk.java.net/jdk/submit/rev/4fe87d390f80

8239785: Cgroups: Incorrect detection logic on old systems in hotspot
Summary: Return NULL subsystem if no cgroup controllers are mounted.
Reviewed-by: duke

! src/hotspot/os/linux/cgroupSubsystem_linux.cpp
! src/hotspot/os/linux/cgroupSubsystem_linux.hpp