On Thu, 23 Jan 2025 14:28:57 GMT, Matthias Ernst <d...@openjdk.org> wrote:
>>> Ah no, the allocate fails of course: >>> >>> ``` >>> java.lang.WrongThreadException: Attempted access outside owning thread >>> at >>> java.base/jdk.internal.foreign.MemorySessionImpl.wrongThread(MemorySessionImpl.java:322) >>> at >>> java.base/jdk.internal.misc.ScopedMemoryAccess$ScopedAccessError.newRuntimeException(ScopedMemoryAccess.java:114) >>> at >>> java.base/jdk.internal.foreign.MemorySessionImpl.checkValidState(MemorySessionImpl.java:217) >>> at >>> java.base/jdk.internal.foreign.SegmentFactories.allocateSegment(SegmentFactories.java:181) >>> at >>> java.base/jdk.internal.foreign.ArenaImpl.allocateNoInit(ArenaImpl.java:52) >>> at java.base/jdk.internal.foreign.ArenaImpl.allocate(ArenaImpl.java:57) >>> at java.base/jdk.internal.foreign.ArenaImpl.allocate(ArenaImpl.java:31) >>> at >>> java.base/java.lang.foreign.SegmentAllocator.allocate(SegmentAllocator.java:644) >>> at >>> java.base/jdk.internal.foreign.abi.BufferStack$PerThread.<init>(BufferStack.java:73) >>> at >>> java.base/jdk.internal.foreign.abi.BufferStack$1.initialValue(BufferStack.java:50) >>> at >>> java.base/jdk.internal.foreign.abi.BufferStack$1.initialValue(BufferStack.java:47) >>> at java.base/java.lang.ThreadLocal.setInitialValue(ThreadLocal.java:224) >>> at java.base/java.lang.ThreadLocal.get(ThreadLocal.java:193) >>> at >>> java.base/java.lang.ThreadLocal.getCarrierThreadLocal(ThreadLocal.java:180) >>> at java.base/java.lang.System$1.getCarrierThreadLocal(System.java:2237) >>> at >>> java.base/jdk.internal.misc.CarrierThreadLocal.get(CarrierThreadLocal.java:39) >>> at >>> java.base/jdk.internal.foreign.abi.BufferStack.pushFrame(BufferStack.java:61) >>> at TestBufferStack.lambda$stress$1(TestBufferStack.java:113) >>> ``` >> >> I was under the impression (which appears incorrect) that `initialValue` >> would be called by the carrier thread as well. So, we basically have a >> mismatch where `initialValue` is called with thread A, but `terminate` is >> called on thread B ? > > Exactly. initialValue happens on-demand, not upfront, i.e. in the very moment > the VT calls get(). > Whereas terminate happens as the last action of the CT. If this is really the case, I agree that there doesn't seem to be an alternative to use `ofAuto`. In which case you don't really need a TerminatingThreadLocal -- a CarrierThreadLocal is just fine (given we don't really have anything to do on close). ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/23142#discussion_r1927077515
