RFR: 8241234: Unify monitor enter/exit runtime entries

[Yudi Zheng]

Hi Dan,

Thanks a lot for stress testing this patch! 
I will push this as soon as I get green lights from the mach5 tests.

Best regards,
-Yudi

> On 1 Apr 2020, at 20:45, Daniel D. Daugherty <daniel.daugherty at oracle.com> wrote:
> 
> Hi Yudi,
> 
> I grabbed a copy of this patch:
> 
> http://cr.openjdk.java.net/~yzheng/8241234/webrev.04/open.patch
> 
> pushed it into my jdk-15+16 baseline and ran it thru a single cycle of
> my regular stress kit (~24 hours). There were no failures which matches
> my jdk-15+16 baseline stress testing (~72 hours, no failures).
> 
> I also ran it through my ObjectMonitor inflation stress kit for ~24
> hours and there were no failures there either.
> 
> Dan
> 
> 
> On 3/30/20 10:20 AM, Daniel D. Daugherty wrote:
>> On 3/30/20 10:15 AM, Yudi Zheng wrote:
>>> Hi Daniel,
>>> 
>>> Thanks for the review! I have uploaded a new version with your comments addressed:
>>> http://cr.openjdk.java.net/~yzheng/8241234/webrev.04/
>>> 
>>>> src/hotspot/share/runtime/sharedRuntime.hpp
>>>>      Please don't forget to update the copyright year before you push.
>>> Fixed.
>>> 
>>>> src/hotspot/share/runtime/sharedRuntime.cpp
>>>>      L2104:   ObjectSynchronizer::exit(obj, lock, THREAD);
>>>>          The use of 'THREAD' here and 'TRAPS' in the function itself
>>>>          standout more now, but that's something for me to cleanup.
>>> Also, I noticed that C2 was using CHECK
>>>>     ObjectSynchronizer::enter(h_obj, lock, CHECK);
>>> While C1 and JVMCI were using THREAD:
>>>>     ObjectSynchronizer::enter(h_obj, lock->lock(), THREAD);
>>> I have no idea when to use what, and hope unifying to the C2 entries would help.
>>> Let me know if there is something I should address in this patch. Otherwise, I would
>>> rather leave it to the expert, i.e., you ;)
>> 
>> Yes, please leave it for me to clean up.
>> 
>> 
>>>> src/hotspot/share/c1/c1_Runtime1.cpp
>>>>      old L718:   assert(thread == JavaThread::current(), "threads must correspond");
>>>>          Removed in favor of the assert in SharedRuntime::monitor_enter_helper().
>>>>          Okay that makes sense.
>>>> 
>>>>      old L721:   EXCEPTION_MARK;
>>>>          Removed in favor of the same in SharedRuntime::monitor_enter_helper().
>>>>          Okay that makes sense.
>>>> 
>>>> src/hotspot/share/jvmci/jvmciRuntime.cpp
>>>>      old L403:   assert(thread == JavaThread::current(), "threads must correspond");
>>>>      old L406:   EXCEPTION_MARK;
>>>>          Same as for c1_Runtime1.cpp
>>> I assume I don’t need to do anything regarding the comments above.
>> 
>> Correct. Just observations on the old code.
>> 
>> 
>>>>      L390:     TRACE_jvmci_3("%s: entered locking slow case with obj="...
>>>>      L394:   TRACE_jvmci_3("%s: exiting locking slow with obj="
>>>>      L417:     TRACE_jvmci_3("%s: exited locking slow case with obj="
>>>>          But this is no longer the "slow" case so I'm a bit confused.
>>>> 
>>>>          Update: I see there's a comment about the tracing being removed.
>>>>          I have no opinion on that since it is JVM/CI code, but the word
>>>>          "slow" needs to be adjusted if you keep it.
>>> I removed all the tracing code.
>> 
>> Thanks for cleaning that up.
>> 
>> Dan
>> 
>>> 
>>> Many thanks,
>>> Yudi
>> 
>