RFR: 8320304: Refactor and simplify monitor deflation functions [v3]

[Stefan Karlsson]

On Mon, 20 Nov 2023 22:47:03 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

>> src/hotspot/share/runtime/synchronizer.cpp line 89:
>> 
>>> 87: }
>>> 88: 
>>> 89: class ObjectMonitorDeflationSafepointer : public StackObj {
>> 
>> FWIW I'm really not seeing the value in abstracting this out into a helper and then passing that object through the API versus simply using a static method like the old `ObjectSynchronizer::chk_for_block_req`. I guess it is a matter of personal style/preference, but I  found it harder to spot where the safepoint checking was actually happening. (Just a comment not a request for change.)
>
> The motivation for this is that I can hide the logging code inside this object instead of passing the LogStream and timer as parameters to the various functions. This simplifies the API, IMHO.

This is a patch that removes the "safepointer" class:
https://github.com/openjdk/jdk/commit/2025d7a8e8d48d2d9af548d95b4a88a57058427c

And this is what the entire patch would look like:
https://github.com/openjdk/jdk/compare/master...stefank:jdk:8320304_cleanup_of_monitor_deflation_no_safepointer

Personally, I think this makes the code messier. Code that previously didn't have to care about logging now has to do so. It is also more obscure what function calls will perform the safepoint checking.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/16706#discussion_r1399867296