JDK-8317677 : Specialize Vtablestubs::entry_for() for VtableBlob
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 21,22
  • Priority: P4
  • Status: Resolved
  • Resolution: Fixed
  • Submitted: 2023-10-06
  • Updated: 2024-04-04
  • Resolved: 2023-10-13
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JDK 21 JDK 22
21.0.4-oracleFixed 22 b20Fixed
Related Reports
Relates :  
JDK-8326092 - Pause Remark sometimes has extremely long pause times on class unloading
Description
CompiledIC::is_icholder_entry() uses Vtablestubs::entry_for() on code blobs known to be VtableBlob instances.

All VtableBlobs are managed by Vtablestubs, i.e. such blobs are trivially always in the VtableStubs table.

Specialization of that entry_for() call allows sidestepping locking the mutex for determining this and avoids the always-succeeding search too.
Comments
Fix request [21u] I backport this for parity with 21.0.4-oracle Low risk. Simple cleanup, already productive in 22. Clean backport. SAP nightly testing passed.
03-04-2024
A pull request was submitted for review. URL: https://git.openjdk.org/jdk21u-dev/pull/432 Date: 2024-04-02 07:35:38 +0000
02-04-2024
Changeset: 1082c0e7 Author: Thomas Schatzl <tschatzl@openjdk.org> Date: 2023-10-13 07:40:00 +0000 URL: https://git.openjdk.org/jdk/commit/1082c0e767a5060d1969edc5ef16f9974e799960
13-10-2023
A pull request was submitted for review. URL: https://git.openjdk.org/jdk/pull/16099 Date: 2023-10-09 10:59:18 +0000
09-10-2023