On Wed, 21 Oct 2020 08:40:47 GMT, Robbin Ehn <r...@openjdk.org> wrote:
>> The main point of this change-set is to make it easier to implement S/R on
>> top of handshakes.
>> Which is a prerequisite for removing _suspend_flag (which duplicates the
>> handshake functionality).
>> But we also remove some complicated S/R methods.
>>
>> We basically just put in everything in the handshake closure, so the diff
>> just looks much worse than what it is.
>>
>> TraceSuspendDebugBits have an ifdef, but in both cases it now just returns.
>> But I was unsure if I should remove now or when is_ext_suspend_completed()
>> is removed.
>>
>> Passes multiple t1-5 runs, locally it passes many
>> jck:vm/nsk_jvmti/nsk_jdi/jdk-jdi runs.
>
> Robbin Ehn has updated the pull request with a new target base due to a merge
> or a rebase. The pull request now contains seven commits:
>
> - Fixed merge miss
> - Merge branch 'master' into
> 8223312-Utilize-handshakes-instead-of-is_thread_fully_suspended
> - Merge fix from Richard
> - Merge branch 'master' into
> 8223312-Utilize-handshakes-instead-of-is_thread_fully_suspended
> - Removed TraceSuspendDebugBits
> - Removed unused method is_ext_suspend_completed_with_lock
> - Utilize handshakes instead of is_thread_fully_suspended
The change is good.
I've only added a few comments (nothing important really).
Thanks, also for giving precedence to me ;)
src/hotspot/share/prims/jvmtiEnvBase.cpp line 1631:
> 1629: _state->set_pending_step_for_popframe();
> 1630: _result = JVMTI_ERROR_NONE;
> 1631: }
I'd suggest to eliminate jt and use java_thread instead. Also because you're
using java_thread in line 1626. The assertion should check if
`_state->get_thread() == target` then.
src/hotspot/share/prims/jvmtiEnv.cpp line 1808:
> 1806: }
> 1807: if (java_lang_Class::is_primitive(k_mirror)) {
> 1808: return JVMTI_ERROR_NONE;
The call of JvmtiSuspendControl::print() seems to be eliminated. Ok for me.
src/hotspot/share/prims/jvmtiEnvBase.cpp line 1454:
> 1452: _state->set_earlyret_pending();
> 1453: _state->set_earlyret_oop(ret_ob_h());
> 1454: _state->set_earlyret_value(_value, _tos);
Good that these updates are done with a handshake now. Maybe I'm missing s.th.
but I don't see synchronization in the older version.
src/hotspot/share/prims/jvmtiEnvBase.hpp line 310:
> 308:
> GrowableArray<jvmtiMonitorStackDepthInfo*> *owned_monitors_list);
> 309: static jvmtiError check_top_frame(Thread* current_thread, JavaThread*
> java_thread,
> 310: jvalue value, TosState tos, Handle*
> ret_ob_h);
Maybe fix indentation?
src/hotspot/share/runtime/deoptimization.cpp line 1771:
> 1769: Deoptimization::deoptimize_frame_internal(thread, id, reason);
> 1770: } else {
> 1771: VM_DeoptimizeFrame deopt(thread, id, reason);
I guess VM_DeoptimizeFrame can be replaced with a handshake too now.
src/hotspot/share/runtime/thread.cpp line 537:
> 535: // cancelled). Returns true if the thread is externally suspended and
> 536: // false otherwise.
> 537: bool JavaThread::is_ext_suspend_completed() {
I'd think `JavaThread::is_ext_suspend_completed` can be removed also (as a
separate enhancement). It also duplicates code of the handshake mechanism. Just
replace VM_ThreadSuspend with a handshake.
-------------
Marked as reviewed by rrich (Committer).
PR: https://git.openjdk.java.net/jdk/pull/729
