> The `interp-only` mechanism is based on the `JavaThread` objects. Carrier and > virtual threads can temporary share the same `JavaThread`. The > `java_thread->jvmti_thread_state()` is re-linked to a virtual thread at > `mount` and to the carrier thread at `unmount`. The `JvmtiThreadState` has a > back link to the `JavaThread` which is also set for virtual thread at a > `mount` and carrier thread at an `unmount`. Just one of these two links at > the same time is set to the `JavaThread`, the other one has to be set to > `nullptr`. The `interp-only` mechanism needs this invariant. > However, there is a corner case when this invariant is broken. It happens > when the `JvmtiThreadState` for carrier thread has just been created. In such > case, the link to `JavaThread` is always `non-nullptr` even though a virtual > thread is currently mounted on a carrier thread. This simple update fixes the > issue in the `JvmtiThreadState` ctor. > > Testing: > - TBD: Mach5 tiers 1-6
Serguei Spitsyn 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 five additional commits since the last revision: - Merge - review: fixed minor typos in newly added comments - review: moved and extended comment in JvmtiThreadState ctor - review: some tweaks for carrier thread JvmtiThreadState initialization - 8373367: interp-only mechanism fails to work for carrier threads in a corner case ------------- Changes: - all: https://git.openjdk.org/jdk/pull/29436/files - new: https://git.openjdk.org/jdk/pull/29436/files/65784f93..61d16e80 Webrevs: - full: https://webrevs.openjdk.org/?repo=jdk&pr=29436&range=04 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29436&range=03-04 Stats: 104163 lines in 1906 files changed: 49820 ins; 24938 del; 29405 mod Patch: https://git.openjdk.org/jdk/pull/29436.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/29436/head:pull/29436 PR: https://git.openjdk.org/jdk/pull/29436
