Harness hook #21
Harness hook #21
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mmtk-jikesrvm/mmtk/src/glue.asm
Line 73 in 3be34fc
harness_begin and harness_end are reentrent, the glue code needs to be updated
| memory_manager::harness_begin(&SINGLETON, tls) | ||
| pub extern "C" fn harness_begin(id: usize) { | ||
| unsafe { | ||
| let thread_from_id = VMCollection::thread_from_id(id); |
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How does the application know thread IDs, which are internal to the VM
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It's the ID from Thread.getId(), which is an application level ID.
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Umm, the application level thread ID Thread.getID() is the same as RVMThread.getCurrentThread().getJavaLangThread().getId().
But VMCollection::thread_from_id expects VMThread.getCurrentThread().threadSlot.
Is there any guarantee/code/documentation that suggests they are the same?
Can you be more specific? |
Any Rust code callable from Java (either implicitly due to allocation, or explicitly due to user requested GC, harness begin, etc.) that may call into Java needs to be wrapper in some glue code written in assembly. See https://gitlab.anu.edu.au/mmtk/jikesrvm/-/issues/39 for details. |
This PR adds proper code so the harness hooks can be invoked by the Rust MMTk probe (https://github.com/mmtk/ci-perf-kit/tree/master/probes/rust_mmtk).
harness_begin()/end()takes the current thread ID as an argument to identify the current thread.harness_begin()/end()takestlsas an argument,tlsis VM specific and we cannot get it from the probe code (application code).harness_begin()/end()is invoked during executing JNI code (IN_JNI), but inside MMTk'sharness_begin(), MMTk will invoke some VM code such asblockForGC(). There are multiple assertions to check if the thread is in a proper state. We need to make sure the thread invokingharness_begin()/end()is set to in a proper state.enter_vm()/leave_vm()to set the thread status toIN_JAVA, and set it back.enter_vm()before callingharness_begin()/end()into MMTk, and callleave_vm()after returning from MMTk.RVMThread.setExecStatus()as public)