[jdk8u-dev] RFR: 8239559: Cgroups: Incorrect detection logic on some systems [v6]

[Jonathan Dowland]

> This is a backport of 53ee0c4963007b86db7979312b81f990e6ce271a via the 11u backport 53ee0c4963007b86db7979312b81f990e6ce271a for cgroups v2 support in jdk8u-dev.
> 
> It isn't clean: context differences in CgroupSubsystemFactory.java around the use of post-8u logging in the original patch.
> 
> I also had to Optional.isEmpty which is not present in 8u's Optional.

Jonathan Dowland has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains eight additional commits since the last revision:

 - Test fix by Severin. Thanks!
 - replace post-jdk8u Optional.isEmpty
 - 8239559: Cgroups: Incorrect detection logic on some systems
   
   Adjust heuristic with cgroup mounts according to mountinfo
   
   Backport-of: 53ee0c4963007b86db7979312b81f990e6ce271a
 - 8240189: [TESTBUG] Some cgroup tests are failing after JDK-8231111
   
   Reviewed-by: mdoerr
   Backport-of: c92adf41587767e9c5c8e116cfaeb375d36928aa
 - Don't pass --add-exports to jdk8u java inside docker
   
   These are JDK9+ module specific parameters.
 - 8244500: jtreg test error in test/hotspot/jtreg/containers/docker/TestMemoryAwareness.java
   
   When the kernel doesn't support swap limits, expect host values instead.
   
   Reviewed-by: sgehwolf
   Backport-of: fb5132254d834ba01a4b65ce64143843e83c674e
 - Update file path in comment
 - Severin's test fixes. Thanks!

-------------

Changes:
  - all: https://git.openjdk.org/jdk8u-dev/pull/136/files
  - new: https://git.openjdk.org/jdk8u-dev/pull/136/files/221ef6a5..54407433

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=136&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=136&range=04-05

  Stats: 71 lines in 4 files changed: 50 ins; 4 del; 17 mod
  Patch: https://git.openjdk.org/jdk8u-dev/pull/136.diff
  Fetch: git fetch https://git.openjdk.org/jdk8u-dev pull/136/head:pull/136

PR: https://git.openjdk.org/jdk8u-dev/pull/136