On Tue, 30 Mar 2021 13:54:58 GMT, Richard Reingruber <rr...@openjdk.org> wrote:
>> Robbin Ehn has updated the pull request with a new target base due to a
>> merge or a rebase. The pull request now contains two commits:
>>
>> - Merge branch 'master' into SuspendInHandshake
>> - 8257831: Suspend with handshake (review baseline)
>
> src/hotspot/share/prims/jvmtiRawMonitor.cpp line 364:
>
>> 362: for (;;) {
>> 363: simple_enter(jt);
>> 364: if (!SafepointMechanism::should_process(jt)) {
>
> It seems to be likely that the condition is false in the first loop iteration
> and the thread has to do another iteration even if not suspended. Wouldn't it
> be ok to break from the loop if `!jt->is_suspended()`?
> I'm asking because in ObjectMonitor::enter() L414 there is similar code and
> the condition there is `SafepointMechanism::should_process(current) &&
> current->suspend_request_pending()`
I didn't add that optimization here because I don't think it is needed, but I
can add it.
> src/hotspot/share/runtime/handshake.cpp line 486:
>
>> 484: // Asynchronous may block so they may not execute
>> ~PreserveExceptionMark before safepointing
>> 485: // in outer loop.
>> 486: op->do_handshake(_handshakee);
>
> Maybe add PauseNoSafepointVerifier to document that the current thread can
> transition to a safe state?
Fixed
-------------
PR: https://git.openjdk.java.net/jdk/pull/3191
