[11u] RFR: 8208677: Move inner metaspace cleaning out of class unloading

[Lindenmaier, Goetz]

Hi Ekaterina,

I understand you want to downport 5 changes to fix 
https://bugs.openjdk.java.net/browse/JDK-8251945, 
starting with this one. 

8251945 is fixed in 11.0.10-oracle. But Oracle did not 
mark these five changes as downported, as they usually
would do.
So I assume they applied a tailored fix to 11 we unfortunately 
can not see, but they did not downport these 5 changes. 

This particular change here seem quite risky to me. 
It changes the behavior of the VM by scheduling
tasks differently and changing safe points.

Isn't it possible to fix the issue more defensively?

Best regards,
  Goetz.



> -----Original Message-----
> From: jdk-updates-dev <jdk-updates-dev-retn at openjdk.java.net> On Behalf
> Of Ekaterina Vergizova
> Sent: Wednesday, September 23, 2020 11:10 PM
> To: jdk-updates-dev at openjdk.java.net
> Subject: [11u] RFR: 8208677: Move inner metaspace cleaning out of class
> unloading
> 
> Hello,
> I would like to backport 8208677 to 11u as a prerequisite for 8210422.
> 8210422 fixes the crash described in 8251945 that is already fixed in 11.0.10-
> oracle.
> The full list of suggested prerequisites is specified in [1].
> 
> JBS: https://bugs.openjdk.java.net/browse/JDK-8208677
> Original patch: http://hg.openjdk.java.net/jdk/jdk/rev/aa3bfacc912c
> Webrev for 11u:
> https://cr.openjdk.java.net/~apetushkov/8208677/webrev.00/
> 
> The patch applies almost cleanly except for the change in
> src/hotspot/share/code/nmethod.cpp.
> It is already included in 11u by 8220718.
> 
> Tested with tier1; the full list of backports specified in [1] is tested with full
> regression.
> 
> Thanks,
> Ekaterina
> 
> [1] https://bugs.openjdk.java.net/browse/JDK-
> 8251945?focusedCommentId=14363860&page=com.atlassian.jira.plugin.sys
> tem.issuetabpanels%3Acomment-tabpanel#comment-14363860