[jdk17] RFR: 8269240: java/foreign/stackwalk/TestAsyncStackWalk.java test failed with concurrent GC [v4]
dholmes at openjdk.java.net
Sat Jul 17 00:37:59 UTC 2021
On Fri, 16 Jul 2021 14:38:35 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:
>> This patch rewrites the prologue and epilogue of panama upcalls, in order to fix the test failure from the title.
>> Previously, we did a call to potentially attach the current thread to the VM, and then afterwards did the same suspend and stack reguard checks that we do on the back-edge of a native downcall. Then, on the back edge of the upcall we did another conditional call to detach the thread.
>> The suspend and reguard checks on the front-edge are incorrect, so I've changed the 2 calls to mimic what is done by JavaCallWrapper instead (with attach and detach included), and removed the old suspend and stack reguard checks.
>> FWIW, this removes the JavaFrameAnchor save/restore MacroAssembler code. This is now written in C++. Also, MacroAssembler code was added to save/restore the result of the upcall around the call on the back-edge, which was previously missing. Since the new code allocates a handle block as well, I've added handling for those oops to frame & OptimizedUpcallBlob.
>> Testing: local running of `jdk_foreign` on Windows and Linux (WSL). Tier 1-3
> Jorn Vernee has updated the pull request incrementally with one additional commit since the last revision:
> Address more review comments
Updates look good.
src/hotspot/share/runtime/thread.hpp line 1427:
> 1425: static inline JavaThread* current();
> 1426: // Returns the current thread as a JavaThread, or NULL if not attached
> 1427: static inline JavaThread* current_or_null();
I hadn't intended to suggest the introduction of this method, but I see now how my comment led to it. It is fine.
Marked as reviewed by dholmes (Reviewer).
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