On Thu, 4 May 2023 23:20:21 GMT, Alex Menkov <amen...@openjdk.org> wrote:
>> The fix updates JVMTI FollowReferences implementation to report references
>> from virtual threads:
>> - unmounted vthreads are detected, their stack references for
>> JVMTI_HEAP_REFERENCE_STACK_LOCAL/JVMTI_HEAP_REFERENCE_JNI_LOCAL;
>> - stacks of mounted vthreads are splitted into 2 parts (virtual thread stack
>> and carrier thread stack), references are reported with correct thread
>> id/class tag/object tags/frame depth;
>> - common code to handle stack frames are moved into separate class;
>>
>> Threads are reported as:
>> - platform threads: JVMTI_HEAP_REFERENCE_THREAD (as before);
>> - mounted vthreads (synthetic references, consider them as heap roots
>> because carrier threads are roots): JVMTI_HEAP_REFERENCE_OTHER;
>> - unmounted vthreads: not reported as heap roots.
>
> Alex Menkov has updated the pull request incrementally with one additional
> commit since the last revision:
>
> Updated test
test/hotspot/jtreg/serviceability/jvmti/vthread/FollowReferences/libVThreadStackRefTest.cpp
line 106:
> 104: extern "C" JNIEXPORT jint JNICALL
> 105: Agent_OnLoad(JavaVM *vm, char *options, void *reserved) {
> 106: if (vm->GetEnv(reinterpret_cast<void **>(&jvmti), JVMTI_VERSION) !=
> JNI_OK || jvmti == nullptr) {
Nit: This line is long and non readable. There are many examples in tests how
it is normally done.
test/hotspot/jtreg/serviceability/jvmti/vthread/FollowReferences/libVThreadStackRefTest.cpp
line 113:
> 111: memset(&capabilities, 0, sizeof(capabilities));
> 112: capabilities.can_tag_objects = 1;
> 113: //capabilities.can_support_virtual_threads = 1;
The line 113 can be removed.
test/hotspot/jtreg/serviceability/jvmti/vthread/FollowReferences/libVThreadStackRefTest.cpp
line 130:
> 128: Java_VThreadStackRefTest_test(JNIEnv* env, jclass clazz, jobjectArray
> classes) {
> 129: jsize classesCount = env->GetArrayLength(classes);
> 130: for (int i=0; i<classesCount; i++) {
Spaces are missed arounf '=' and '<' signs.
test/hotspot/jtreg/serviceability/jvmti/vthread/FollowReferences/libVThreadStackRefTest.cpp
line 154:
> 152: }
> 153:
> 154: static void printtCreatedClass(JNIEnv* env, jclass cls) {
Why is printt with 'tt' ?
test/hotspot/jtreg/serviceability/jvmti/vthread/FollowReferences/libVThreadStackRefTest.cpp
line 167:
> 165:
> 166: extern "C" JNIEXPORT void JNICALL
> 167: Java_VThreadStackRefTest_createObjAndCallback(JNIEnv* env, jclass clazz,
> jclass cls, jobject callback) {
Some comment would be helpful about what this function does.
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/13254#discussion_r1185720838
PR Review Comment: https://git.openjdk.org/jdk/pull/13254#discussion_r1185720066
PR Review Comment: https://git.openjdk.org/jdk/pull/13254#discussion_r1185721404
PR Review Comment: https://git.openjdk.org/jdk/pull/13254#discussion_r1185722065
PR Review Comment: https://git.openjdk.org/jdk/pull/13254#discussion_r1185722636
