RFR: 8308745: ObjArrayKlass::allocate_objArray_klass may call into java while holding a lock

[Dean Long]

On Tue, 6 Feb 2024 22:59:04 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

> This change creates a new sort of native recursive lock that can be held during JNI and Java calls, which can be used for synchronization while creating objArrayKlasses at runtime.
> 
> Passes tier1-7.

OK, that makes sense about loom and JOM.

src/hotspot/share/runtime/mutex.cpp line 537:

> 535:     // can be called by jvmti by VMThread.
> 536:     if (current->is_Java_thread()) {
> 537:       _sem.wait_with_safepoint_check(JavaThread::cast(current));

Why not use PlatformMutex + OSThreadWaitState instead of a semaphore?

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PR Comment: https://git.openjdk.org/jdk/pull/17739#issuecomment-1982008253
PR Review Comment: https://git.openjdk.org/jdk/pull/17739#discussion_r1515269443