On Fri, 26 Apr 2024 19:34:55 GMT, Chris Plummer <cjplum...@openjdk.org> wrote:
>> Serguei Spitsyn has updated the pull request incrementally with one >> additional commit since the last revision: >> >> review: fixed minor issues: renamed function, corrected comment, removed >> typo in assert > > src/hotspot/share/prims/jvmtiThreadState.cpp line 366: > >> 364: attempts--; >> 365: } >> 366: DEBUG_ONLY(if (attempts == 0) break;) > > Previously `_VTMS_transition_count` considered all threads at the same time. > Now you are iterating through the threads and looking at a flag in each one. > Is it guaranteed that once the `_VTMS_transition_mark` flag has been verified > not to be set in a thread it won't get set while still iterating in the > threads loop? Thank you for the comment. It is thinking in a right direction. Each `JavaThread` set the `VTM_transition_mark` only once and then checks for disable counters: - `_VTMS_transition_disable_for_all_count` - `java_lang_Thread::VTMS_transition_disable_count(vth())` If any of the disable counters is not zero then each `JavaThread` clears the optimistically set mark and continues under protection of the `JvmtiVTMSTransition_lock`. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/18937#discussion_r1584025182
