[jdk8u-dev] RFR: 8230305: Cgroups v2: Container awareness [v7]

[Jonathan Dowland]

> This is a backport of 8230305 (Cgroups v2: Container awareness) for JDK8u, working from the jdk11u-dev backport as part of an effort to backport cgroups v2 to jdk8u-dev.
> 
> The patch does not apply clean after unshuffling and path fixing:
> 
>  * mostly copyright line issues
>  * different package name for jdk.test.lib.process.OutputAnalyzer
>  * Most of hotspot/src/os/linux/vm/cgroupSubsystem_linux.cpp failed due to context changes, manually resolved (mostly deletions)
> 
> A few other changes were made
> 
>  *  Rework use of newer logging API (log_debug etc) to use guarded tty->print_cr
>  *  replace os::strerror with the libc strerror (which is thread unsafe, but that should be addressed by backporting 8148425 separately)
> 
> patch touched hotspot/test/runtime/containers/docker/TestCPUAwareness.java which passes afterwards; I'm running further tests now (and awaiting GitHub CI doing the same)

Jonathan Dowland has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains six new commits since the last revision:

 - Remove C++11-style non-static member initialisation
   
   This causes issues with pre-C++11 compilers (of which jdk8u-dev
   ostensibly supports). Issue has materialised on ARM32.
   
   I haven't introduced initialiser lists to the constructor because
   all of these are assigned to in the body of the constructor.
 - Guard two more tty->print_cr with PrintContainerInfo
 - Whitespace and braces around PrintContainerInfo
 - substitute os::strerror for strerror
   
   os::strerror was introduced in 8148425 (strerror() function is not
   thread-safe), which is probably out of scope for backporting (at least
   as part of this cgroups v2 effort). Replace uses of os::strerror with
   (thread unsafe) strerror, in common with the rest of JDK8u.
 - Rework use of newer logging API to tty->print_cr
   
   Remove includes of log.hpp that doesn't exist in jdk8u
   
   log_(debug|trace) to tty->print_cr guarded by PrintContainerInfo
 - 8230305: Cgroups v2: Container awareness
   
   Implement Cgroups v2 container awareness in hotspot
   
   Reviewed-by: bobv, dholmes

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

Changes:
  - all: https://git.openjdk.org/jdk8u-dev/pull/127/files
  - new: https://git.openjdk.org/jdk8u-dev/pull/127/files/6947cdb7..198cd274

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=127&range=06
 - incr: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=127&range=05-06

  Stats: 5334 lines in 33 files changed: 1581 ins; 3620 del; 133 mod
  Patch: https://git.openjdk.org/jdk8u-dev/pull/127.diff
  Fetch: git fetch https://git.openjdk.org/jdk8u-dev pull/127/head:pull/127

PR: https://git.openjdk.org/jdk8u-dev/pull/127