RFR: 8273251: Call check_possible_safepoint() from SafepointMechanism::process_if_requested()

[Coleen Phillimore]

On Wed, 1 Sep 2021 20:53:46 GMT, Patricio Chilano Mateo <pchilanomate at openjdk.org> wrote:

> Hi,
> 
> Please review this small fix to call check_possible_safepoint() from SafepointMechanism::process_if_requested() and remove the same call from transition_and_process(). See the bug description for more detail.
> Since there were only two lines left of common code from transition_from_native() and transition_from_vm() I just removed transition_and_process() altogether. This also saves an unneeded extra transition to _thread_in_vm when transitioning from vm to Java.
> 
> Testing tiers 1-6.
> 
> Thanks,
> Patricio

Looks good to me!

src/hotspot/share/runtime/interfaceSupport.inline.hpp line 81:

> 79: 
> 80:  private:
> 81:   static inline void transition_and_process(JavaThread *thread, JavaThreadState to, bool check_asyncs) {

��

src/hotspot/share/runtime/thread.cpp line 959:

> 957:     assert_wx_state(WXWrite);
> 958:   }
> 959: #endif

I was wondering why you moved this, but it's assert code so it makes sense to me to be with the other assert code.  Maybe check_possible_safepoint could have a better name to encompass all these checking and assertions actions but I don't know what better name to give it.
With this code moved here, all the other callers where there's a possible safepoint but one not taken will also check this.  Did you test on macosx aarch64 too?

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Marked as reviewed by coleenp (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/5342