On Thu, 17 Jun 2021 05:15:36 GMT, Denghui Dong <dd...@openjdk.org> wrote:
>> Hi, >> >> Could I have a review of this change that merges three vm >> operations(VM_PrintThreads, VM_PrintJNI, VM_FindDeadlocks) in thread_dump >> and signal_thread_entry. >> >> `jstack` is a very common command, even in the production environment. >> >> In addition to reduce the cost of entering safepoint, I think this patch >> also could ensure the consistency of the results of VM_PrintThreads and >> VM_FindDeadlocks. > > Denghui Dong has updated the pull request incrementally with three additional > commits since the last revision: > > - update > - remove useless comment > - remove VM_PrintJNI So the PR is open again but I see no substantive changes that address my concerns. I don't see how there can be any fix here when the desired goal is one safepoint and the problem is that one safepoint may be far too long. And I don't see any way to force a timeout in a VM operation, or anything it calls. I realize there can be a discrepancy between the sets of threads involved, but I think that is just the trade-off we have to make for this diagnostic tool. ------------- PR: https://git.openjdk.java.net/jdk/pull/4504
