On Wed, 7 Jun 2023 22:42:49 GMT, Alex Menkov <[email protected]> wrote:
>> Good concern.
>> There are two bits (and the related RUNNABLE bit) that we care in this
>> sub-tree of state bits: `SUSPENDED` and `INTERRUPTED`. This update clones
>> these two bits. The RUNNABLE bit must be cleared.
>> A thread carrying a virtual thread can not be in native, blocked, parked,
>> sleeping or waiting on some object.
>> The state returned by the `get_thread_state_base` is based on the call:
>> ` state = (jint)java_lang_Thread::get_thread_status(thread_oop);`
>> and addition of the derived from JavaThread bits: `SUSPENDED`, `INTERRUPTED`
>> and `IN_NATIVE`.
>> The three bits derived from the JavaThread are not relevant.
>> This call has to be made directly:
>> ` state = (jint)java_lang_Thread::get_thread_status(thread_oop);`
>> The SUSPEND bit has to be based on the call:
>> ` jt->is_carrier_thread_suspended();`
>>
>> The function `get_thread_state` will look as below:
>>
>> if (is_thread_carrying_vthread(jt, thread_oop)) {
>> jint state = (jint)java_lang_Thread::get_thread_status(thread_oop);
>> if (jt->is_carrier_thread_suspended()) {
>> state |= JVMTI_THREAD_STATE_SUSPENDED;
>> }
>> // It's okay for the JVMTI state to be reported as WAITING when waiting
>> // for something other than an Object.wait. So, we treat a thread
>> carrying
>> // a virtual thread as waiting indefinitely which is not runnable.
>> // It is why the RUNNABLE bit is cleared and the WAITING bits are added.
>> state &= ~JVMTI_THREAD_STATE_RUNNABLE;
>> state |= JVMTI_THREAD_STATE_WAITING |
>> JVMTI_THREAD_STATE_WAITING_INDEFINITELY;
>> return state;
>> } else {
>> return get_thread_state_base(thread_oop, jt);
>> }
>
> Do you need to check jt->is_interrupted(false) and set INTERRUPTED bit?
> It looks like java_lang_Thread::get_thread_status(thread_oop) can only return
> RUNNABLE in the case and we clear it, so the call is not needed:
>
> if (is_thread_carrying_vthread(jt, thread_oop)) {
> jint state = JVMTI_THREAD_STATE_WAITING |
> JVMTI_THREAD_STATE_WAITING_INDEFINITELY;
> if (jt->is_carrier_thread_suspended()) {
> state |= JVMTI_THREAD_STATE_SUSPENDED;
> }
> if (jt->is_interrupted(false)) {
> state |= JVMTI_THREAD_STATE_INTERRUPTED;
> }
> return state;
> } else ...
> A thread carrying a virtual thread can not be in native, blocked, parked,
> sleeping or waiting on some object.
Actually it can be in native.
And if I remember correctly synchronized block pins virtual thread, so inside
synchronized we can get other states
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PR Review Comment: https://git.openjdk.org/jdk/pull/14366#discussion_r1222255498
