On Mon, 4 Sep 2023 08:24:19 GMT, Alan Bateman <al...@openjdk.org> wrote:
>> In the virtual thread implementation, thread identity switches to the >> carrier before freezing and switches back to the virtual thread after >> thawing. This was a forced move due to issues getting JVMTI to work with >> virtual threads. JVMTI can now hide events during transitions so we can >> invert the sequence back to mounting before running the continuation, >> unmounting after freezing, and re-mounting after thawing. This sequence is >> important for future changes that will initiate the freezing from the VM. >> >> The change requires an update to the JFR thread sampler to skip sampling >> when it samples during a transition. >> >> Testing: tier1-5 > > Alan Bateman 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 three additional > commits since the last revision: > > - Check for transition during stack walk for synchronous case > - Merge > - Initial commit The fix looks okay to me. From JVMTI point of view this transition is hidden, so no inconsistency can be observed. However, I wonder if the AsyncGetStackTraces may have similar issue as the JFR had. Unfortunately we do not have good test coverage to rely on. Thanks, Serguei ------------- Marked as reviewed by sspitsyn (Reviewer). PR Review: https://git.openjdk.org/jdk/pull/15492#pullrequestreview-1612449636
