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.

src/hotspot/share/oops/arrayKlass.cpp line 135:

> 133:     ResourceMark rm(THREAD);
> 134:     {
> 135:       // Ensure atomic creation of higher dimensions

Isn't this comment still useful?

src/hotspot/share/oops/arrayKlass.cpp line 144:

> 142:         ObjArrayKlass* ak =
> 143:           ObjArrayKlass::allocate_objArray_klass(class_loader_data(), dim + 1, this, CHECK_NULL);
> 144:         ak->set_lower_dimension(this);

Would it be useful to assert that the lower dimension has been set?

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PR Review Comment: https://git.openjdk.org/jdk/pull/17739#discussion_r1515322667
PR Review Comment: https://git.openjdk.org/jdk/pull/17739#discussion_r1515323404