RFR: 8271931: Make AbortVMOnVMOperationTimeout more resilient to OS scheduling

Aleksey Shipilev shade at openjdk.java.net
Thu Aug 5 10:30:30 UTC 2021

On Thu, 5 Aug 2021 09:47:18 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

> Perform VM-op timeout also on the VM thread. If a VM-op is stuck, the existing watcher-thread based machinery will kick in and detect it.
> Test: tier1

TBH, the decision to only check this at periodic task was to avoid excess overhead. But I don't think this concern is relevant for this patch, as it would only be entered when timeout is enabled. I do have suggestions to simplify the patch:

src/hotspot/share/runtime/vmThread.cpp line 428:

> 426:         fatal("%s VM operation took too long: completed in " JLONG_FORMAT " ms (timeout: " INTX_FORMAT " ms)",
> 427:               _cur_vm_operation->name(), delay, AbortVMOnVMOperationTimeoutDelay);
> 428:       }

This duplicates `VMOperationTimeoutTask::task` body. So I think this is better to be moved to a separate method, e.g. `VMOperationTimeoutTask::check_and_fail`, which we can then call from both `::task` and `::disarm`.


Changes requested by shade (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/5016

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