RFR: 8302462: [REDO] 8297487: G1 Remark: no need to keep alive oop constants of nmethods on stack [v2]

[Richard Reingruber]

On Tue, 14 Feb 2023 20:55:20 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

>> src/hotspot/share/gc/shared/barrierSet.cpp line 64:
>> 
>>> 62:     // the constant pool of nmethods as part of the SATB snapshot, and to deal with
>>> 63:     // compiled frames contained in continuation stack chunks allocated after
>>> 64:     // concurent mark start.
>> 
>> I've adapted the comment after https://mail.openjdk.org/pipermail/hotspot-gc-dev/2023-January/041194.html
>
> I feel the comment is at the wrong level of abstraction, compared with the surrounding code.
> 
> Maybe just `Provide nmethod entry barrier to support concurrent marking and code cache unloading.` at the top of the whole method.
> 
> The more elaborate "inside" about nmethod-entry-barrier probably makes more sense at `BarrierSetNMethod::nmethod_entry_barrier`.

You are right. I've reverted that change and added a line of comment to `BarrierSetNMethod::nmethod_entry_barrier`

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

PR: https://git.openjdk.org/jdk/pull/12561