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disable the profiler if -XX:+UseAdaptiveGCBoundary is set #9

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Merged
richardstartin merged 1 commit into from
Aug 23, 2023
Merged

disable the profiler if -XX:+UseAdaptiveGCBoundary is set #9

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4 changes: 4 additions & 0 deletions ddprof-lib/src/main/cpp/profiler.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1000,6 +1000,10 @@ Error Profiler::checkJvmCapabilities() {
return Error("Could not find VMThread bridge. Unsupported JVM?");
}

if (VM::isUseAdaptiveGCBoundarySet()) {
return Error("The user has explicitly set -XX:+UseAdaptiveGCBoundary so the profiler has been disabled to avoid the risk of crashing.");
}

if (_dlopen_entry == NULL) {
CodeCache* lib = findJvmLibrary("libj9prt");
if (lib == NULL || (_dlopen_entry = lib->findGlobalOffsetEntry((void*)dlopen)) == NULL) {
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8 changes: 8 additions & 0 deletions ddprof-lib/src/main/cpp/vmEntry.cpp
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Expand Up @@ -45,6 +45,7 @@ bool VM::_hotspot = false;
bool VM::_zing = false;
bool VM::_can_sample_objects = false;
bool VM::_can_intercept_binding = false;
bool VM::_is_adaptive_gc_boundary_flag_set = false;
jobject VM::_global_system_classloader = nullptr;
jobject VM::_global_platform_classloader = nullptr;

Expand Down Expand Up @@ -291,6 +292,13 @@ bool VM::init(JavaVM* vm, bool attach) {
}
}

// if the user sets -XX:+UseAdaptiveGCBoundary we will just disable the profiler to avoid the risk of crashing
// flag was made obsolete (inert) in 15 (see JDK-8228991) and removed in 16 (see JDK-8231560)
if (java_version() < 15) {
char* flag_addr = (char*)JVMFlag::find("UseAdaptiveGCBoundary");
_is_adaptive_gc_boundary_flag_set = flag_addr != NULL && *flag_addr == 1;
}

if (attach) {
loadAllMethodIDs(jvmti(), jni());
_jvmti->GenerateEvents(JVMTI_EVENT_DYNAMIC_CODE_GENERATED);
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5 changes: 5 additions & 0 deletions ddprof-lib/src/main/cpp/vmEntry.h
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Expand Up @@ -100,6 +100,7 @@ class VM {
static bool _zing;
static bool _can_sample_objects;
static bool _can_intercept_binding;
static bool _is_adaptive_gc_boundary_flag_set;

static jobject _global_system_classloader;
static jobject _global_platform_classloader;
Expand Down Expand Up @@ -170,6 +171,10 @@ class VM {
return _zing;
}

static bool isUseAdaptiveGCBoundarySet() {
return _is_adaptive_gc_boundary_flag_set;
}

static bool isSystemClassLoader(JNIEnv* jni, jobject& cl);

static void JNICALL VMInit(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread);
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