On Mon, 28 Oct 2024 20:49:45 GMT, Patricio Chilano Mateo
<pchilanom...@openjdk.org> wrote:
>> src/hotspot/cpu/x86/sharedRuntime_x86_64.cpp line 2382:
>>
>>> 2380: __ bind(after_transition);
>>> 2381:
>>> 2382: if (LockingMode != LM_LEGACY && method->is_object_wait0()) {
>>
>> It bothers me that we have to add a check for a specific native method in
>> this code (notwithstanding there are already some checks in relation to
>> hashCode). As a follow up I wonder if we can deal with wait-preemption by
>> rewriting the Java code, instead of special casing the wait0 native code?
>
> Not sure. We would have to return from wait0 and immediately clear the
> physical stack from the frames just copied without safepoint polls in the
> middle. Otherwise if someone walks the thread's stack it will find the frames
> appearing twice: in the physical stack and in the heap.
It's conceivable that in the future we might have more native methods we want
to preempt. Instead of enumerating them all, we could set a flag on the method.
I was assuming that David was suggesting we have the Java caller do a yield()
or something, instead of having the native code call freeze.
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/21565#discussion_r1819880228
