(0.45) ScopedMemoryAccess closeScope0 Updates #19433
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In JDK22, the definition has changed to native void closeScope0(MemorySessionImpl session, ScopedAccessError error); The return type has changed from boolean to void, and a second parameter is re-introduced: "ScopedAccessError error". Previously, closeScope0 would be retried until it returned true, which suggested that the scope/session was not found on any thread's stack. The new behaviour sets an asynchronous exception for all threads, which have the scope/session on their stack. The second parameter, error, is the asynchronous exception, which is thrown. Before throwing the error, the thread verifies if the scope/session is still on the stack. If not, the asynchronous exception is cleared and not thrown. Related: eclipse-openj9#13211 (comment) Signed-off-by: Babneet Singh <[email protected]>
There are gaps where async exceptions are not processed in time (e.g. JIT compiled code in a loop). Threads will wait in closeScope0 until J9VMThread->scopedError (async exception) is transferred to J9VMThread->currentException. The wait prevents a MemorySession to be closed until no more operations are being performed on it. Related: eclipse-openj9#13211 Signed-off-by: Babneet Singh <[email protected]>
babsingh
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pshipton
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May 2, 2024
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This PR backports the following two PRs to 0.45:
Related: #13211