JDK-8315498 : Release Note: The Linux Specific Options `UseSHM` and `UseHugeTLBFS` Are Now Obsolete
  • Type: Sub-task
  • Component: hotspot
  • Sub-Component: runtime
  • Affected Version: 22
  • Priority: P4
  • Status: Resolved
  • Resolution: Delivered
  • OS: linux
  • Submitted: 2023-09-01
  • Updated: 2024-02-16
  • Resolved: 2023-11-17
The Version table provides details related to the release that this issue/RFE will be addressed.

Unresolved : Release in which this issue/RFE will be addressed.
Resolved: Release in which this issue/RFE has been resolved.
Fixed : Release in which this issue/RFE has been fixed. The release containing this fix may be available for download as an Early Access Release or a General Availability Release.

To download the current JDK release, click here.
JDK 22
22Resolved
Description
On Linux, if `UseLargePages` is enabled and `UseTransparentHugePages` is disabled, *static* or *explicit* large page mode, the options `UseSHM` and `UseHugeTLBFS` existed to switch between the two different implementations: 

- `UseHugeTLBFS` would cause the JVM to use POSIX APIs for allocating large pages. 
- `UseSHM` would let the JVM would use System V APIs. `UseHugeTLBFS` had been the default if both options were omitted.

The `UseSHM` mode offered no advantage over `UseHugeTLBFS` and has therefore been removed. The switch `UseSHM` has been obsoleted.

The JVM will now always use POSIX APIs for managing large pages. The switch `UseHugeTLBFS` has also been obsoleted;  `UseHugeTLBFS` is now unconditionally enabled and cannot be switched off.
Comments
[~dholmes] Thanks for catching that; I fixed the title. [~jwilhelm] Thank you, will do.
17-11-2023
[~stuefe] The title says "deprecated" and the RN text says "obsoleted" - they need to match
17-11-2023
Yes, the release note process (https://openjdk.org/guide/#release-notes) says that you should Resolve the sub-task as Delivered.
16-11-2023
I'm unsure what the process is here. Do I just close this issue, since the issue text is the release note? Oracle, help.
16-11-2023
I moved the parent Bug to RT and therefore changed this Bug back to RT.
07-09-2023