RFR: 8241234: Unify monitor enter/exit runtime entries

[coleen.phillimore at oracle.com]

This seems like a good thing to do:

http://cr.openjdk.java.net/~yzheng/8241234/webrev.00/src/hotspot/share/runtime/sharedRuntime.cpp.udiff.html

I think you should have monitor_enter_helper and maybe 
monitor_exi_helper both take Handle as arguments.  This looks very strange.

+void SharedRuntime::monitor_enter_helper(oopDesc* _obj, BasicLock* 
lock, JavaThread* thread) {

Because it creates a Handle anyway.  We try to eagerly pass Handle so 
that we don't have to search through the code to make sure there aren't 
any unhandled oops.

The _obj parameter name doesn't follow coding conventions (I was looking 
for it to be a field in something).

+ oop obj(_obj);


Is there not already a implicit conversion from oopDesc* to oop?

Thanks,
Coleen


On 3/20/20 11:03 AM, Yudi Zheng wrote:
> Hello,
>
> Please review this patch that unifies the monitor enter/exit runtime entries used by C1, C2, and JVMCI.
>
> https://bugs.openjdk.java.net/browse/JDK-8061553 added support for faster "slow" locking paths.
> These paths are not currently used by JVMCI (or C1) leading to slower performance on programs
> that have a lot of short lived locked sections (such as dacapo:h2).
>
> This patch creates helper methods based on C2’s monitor enter/exit entries, and shares with the C1,
> JVMCI runtimes. It will prevent these runtimes from missing future updates.
>
> https://bugs.openjdk.java.net/browse/JDK-8241234
> http://cr.openjdk.java.net/~yzheng/8241234/webrev.00/
>
> Many thanks,
> Yudi