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8296492: Remove ObjectLocker in JVMTI get_subgroups call

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Reviewed-by: dholmes, alanb, sspitsyn
This commit is contained in:
Coleen Phillimore 2022-11-17 11:58:00 +00:00
parent 171553a611
commit d8c809b196
7 changed files with 56 additions and 100 deletions
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32
src/hotspot/share/classfile/javaClasses.cpp
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@ -1995,10 +1995,6 @@ int java_lang_ThreadGroup::_parent_offset;
int java_lang_ThreadGroup::_name_offset;
int java_lang_ThreadGroup::_maxPriority_offset;
int java_lang_ThreadGroup::_daemon_offset;
int java_lang_ThreadGroup::_ngroups_offset;
int java_lang_ThreadGroup::_groups_offset;
int java_lang_ThreadGroup::_nweaks_offset;
int java_lang_ThreadGroup::_weaks_offset;
oop java_lang_ThreadGroup::parent(oop java_thread_group) {
assert(oopDesc::is_oop(java_thread_group), "thread group must be oop");
@ -2026,37 +2022,11 @@ bool java_lang_ThreadGroup::is_daemon(oop java_thread_group) {
return java_thread_group->bool_field(_daemon_offset) != 0;
}
int java_lang_ThreadGroup::ngroups(oop java_thread_group) {
assert(oopDesc::is_oop(java_thread_group), "thread group must be oop");
return java_thread_group->int_field(_ngroups_offset);
}
objArrayOop java_lang_ThreadGroup::groups(oop java_thread_group) {
oop groups = java_thread_group->obj_field(_groups_offset);
assert(groups == NULL || groups->is_objArray(), "just checking"); // Todo: Add better type checking code
return objArrayOop(groups);
}
int java_lang_ThreadGroup::nweaks(oop java_thread_group) {
assert(oopDesc::is_oop(java_thread_group), "thread group must be oop");
return java_thread_group->int_field(_nweaks_offset);
}
objArrayOop java_lang_ThreadGroup::weaks(oop java_thread_group) {
oop weaks = java_thread_group->obj_field(_weaks_offset);
assert(weaks == NULL || weaks->is_objArray(), "just checking");
return objArrayOop(weaks);
}
#define THREADGROUP_FIELDS_DO(macro) \
macro(_parent_offset, k, vmSymbols::parent_name(), threadgroup_signature, false); \
macro(_name_offset, k, vmSymbols::name_name(), string_signature, false); \
macro(_maxPriority_offset, k, vmSymbols::maxPriority_name(), int_signature, false); \
macro(_daemon_offset, k, vmSymbols::daemon_name(), bool_signature, false); \
macro(_ngroups_offset, k, vmSymbols::ngroups_name(), int_signature, false); \
macro(_groups_offset, k, vmSymbols::groups_name(), threadgroup_array_signature, false); \
macro(_nweaks_offset, k, vmSymbols::nweaks_name(), int_signature, false); \
macro(_weaks_offset, k, vmSymbols::weaks_name(), weakreference_array_signature, false);
macro(_daemon_offset, k, vmSymbols::daemon_name(), bool_signature, false);
void java_lang_ThreadGroup::compute_offsets() {
assert(_parent_offset == 0, "offsets should be initialized only once");

15
src/hotspot/share/classfile/javaClasses.hpp
View file

@ -479,13 +479,7 @@ class java_lang_ThreadGroup : AllStatic {
static int _maxPriority_offset;
static int _daemon_offset;
static int _ngroups_offset;
static int _groups_offset;
static int _nweaks_offset;
static int _weaks_offset;
static void compute_offsets();
public:
static void serialize_offsets(SerializeClosure* f) NOT_CDS_RETURN;
@ -498,15 +492,6 @@ class java_lang_ThreadGroup : AllStatic {
// Daemon
static bool is_daemon(oop java_thread_group);
// Number of strongly reachable thread groups
static int ngroups(oop java_thread_group);
// Strongly reachable thread groups
static objArrayOop groups(oop java_thread_group);
// Number of weakly reachable thread groups
static int nweaks(oop java_thread_group);
// Weakly reachable thread groups
static objArrayOop weaks(oop java_thread_group);
// Debugging
friend class JavaClasses;
};

5
src/hotspot/share/classfile/vmSymbols.hpp
View file

@ -400,10 +400,6 @@
template(exit_method_name, "exit") \
template(remove_method_name, "remove") \
template(parent_name, "parent") \
template(ngroups_name, "ngroups") \
template(groups_name, "groups") \
template(nweaks_name, "nweaks") \
template(weaks_name, "weaks") \
template(maxPriority_name, "maxPriority") \
template(shutdown_name, "shutdown") \
template(finalize_method_name, "finalize") \
@ -607,6 +603,7 @@
template(thread_void_signature, "(Ljava/lang/Thread;)V") \
template(threadgroup_runnable_void_signature, "(Ljava/lang/ThreadGroup;Ljava/lang/Runnable;)V") \
template(threadgroup_string_void_signature, "(Ljava/lang/ThreadGroup;Ljava/lang/String;)V") \
template(void_threadgroup_array_signature, "()[Ljava/lang/ThreadGroup;") \
template(string_class_signature, "(Ljava/lang/String;)Ljava/lang/Class;") \
template(string_boolean_class_signature, "(Ljava/lang/String;Z)Ljava/lang/Class;") \
template(object_object_object_signature, "(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;") \

2
src/hotspot/share/prims/jvmtiEnv.cpp
View file

@ -1670,7 +1670,7 @@ JvmtiEnv::GetThreadGroupChildren(jthreadGroup group, jint* thread_count_ptr, jth
NULL_CHECK(group_obj, JVMTI_ERROR_INVALID_THREAD_GROUP);
Handle *thread_objs = NULL;
Handle *group_objs = NULL;
objArrayHandle group_objs;
jint nthreads = 0;
jint ngroups = 0;
int hidden_threads = 0;

87
src/hotspot/share/prims/jvmtiEnvBase.cpp
View file

@ -26,6 +26,7 @@
#include "classfile/classLoaderDataGraph.hpp"
#include "classfile/javaClasses.inline.hpp"
#include "classfile/moduleEntry.hpp"
#include "classfile/symbolTable.hpp"
#include "jvmtifiles/jvmtiEnv.hpp"
#include "memory/iterator.hpp"
#include "memory/resourceArea.hpp"
@ -46,6 +47,7 @@
#include "runtime/frame.inline.hpp"
#include "runtime/handles.inline.hpp"
#include "runtime/interfaceSupport.inline.hpp"
#include "runtime/javaCalls.hpp"
#include "runtime/javaThread.inline.hpp"
#include "runtime/jfieldIDWorkaround.hpp"
#include "runtime/jniHandles.inline.hpp"
@ -534,29 +536,34 @@ void JvmtiEnvBase::destroy_jni_reference(JavaThread *thread, jobject jobj) {
// Threads
//
jobject *
JvmtiEnvBase::new_jobjectArray(int length, Handle *handles) {
jthread *
JvmtiEnvBase::new_jthreadArray(int length, Handle *handles) {
if (length == 0) {
return NULL;
}
jobject *objArray = (jobject *) jvmtiMalloc(sizeof(jobject) * length);
jthread* objArray = (jthread *) jvmtiMalloc(sizeof(jthread) * length);
NULL_CHECK(objArray, NULL);
for (int i=0; i<length; i++) {
objArray[i] = jni_reference(handles[i]);
for (int i = 0; i < length; i++) {
objArray[i] = (jthread)jni_reference(handles[i]);
}
return objArray;
}
jthread *
JvmtiEnvBase::new_jthreadArray(int length, Handle *handles) {
return (jthread *) new_jobjectArray(length,handles);
}
jthreadGroup *
JvmtiEnvBase::new_jthreadGroupArray(int length, Handle *handles) {
return (jthreadGroup *) new_jobjectArray(length,handles);
JvmtiEnvBase::new_jthreadGroupArray(int length, objArrayHandle groups) {
if (length == 0) {
return NULL;
}
jthreadGroup* objArray = (jthreadGroup *) jvmtiMalloc(sizeof(jthreadGroup) * length);
NULL_CHECK(objArray, NULL);
for (int i = 0; i < length; i++) {
objArray[i] = (jthreadGroup)JNIHandles::make_local(groups->obj_at(i));
}
return objArray;
}
// Return the vframe on the specified thread and depth, NULL if no such frame.
@ -792,43 +799,33 @@ JvmtiEnvBase::get_live_threads(JavaThread* current_thread, Handle group_hdl, jin
}
jvmtiError
JvmtiEnvBase::get_subgroups(JavaThread* current_thread, Handle group_hdl, jint *count_ptr, Handle **group_objs_p) {
ObjectLocker ol(group_hdl, current_thread);
JvmtiEnvBase::get_subgroups(JavaThread* current_thread, Handle group_hdl, jint *count_ptr, objArrayHandle *group_objs_p) {
int ngroups = java_lang_ThreadGroup::ngroups(group_hdl());
int nweaks = java_lang_ThreadGroup::nweaks(group_hdl());
jint count = 0;
Handle *group_objs = NULL;
if (ngroups > 0 || nweaks > 0) {
group_objs = NEW_RESOURCE_ARRAY_RETURN_NULL(Handle, ngroups + nweaks);
NULL_CHECK(group_objs, JVMTI_ERROR_OUT_OF_MEMORY);
if (ngroups > 0) {
// Strongly reachable subgroups:
objArrayOop groups = java_lang_ThreadGroup::groups(group_hdl());
for (int j = 0; j < ngroups; j++) {
oop group_obj = groups->obj_at(j);
assert(group_obj != NULL, "group_obj != NULL");
group_objs[count++] = Handle(current_thread, group_obj);
// This call collects the strong and weak groups
JavaThread* THREAD = current_thread;
JavaValue result(T_OBJECT);
JavaCalls::call_virtual(&result,
group_hdl,
vmClasses::ThreadGroup_klass(),
SymbolTable::new_permanent_symbol("subgroupsAsArray"),
vmSymbols::void_threadgroup_array_signature(),
THREAD);
if (HAS_PENDING_EXCEPTION) {
Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
CLEAR_PENDING_EXCEPTION;
if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
return JVMTI_ERROR_OUT_OF_MEMORY;
} else {
return JVMTI_ERROR_INTERNAL;
}
}
if (nweaks > 0) {
// Weakly reachable subgroups:
objArrayOop weaks = java_lang_ThreadGroup::weaks(group_hdl());
for (int j = 0; j < nweaks; j++) {
oop weak_obj = weaks->obj_at(j);
assert(weak_obj != NULL, "weak_obj != NULL");
oop group_obj = java_lang_ref_Reference::weak_referent(weak_obj);
if (group_obj != NULL) {
group_objs[count++] = Handle(current_thread, group_obj);
}
}
}
}
*group_objs_p = group_objs;
*count_ptr = count;
assert(result.get_type() == T_OBJECT, "just checking");
objArrayOop groups = (objArrayOop)result.get_oop();
*count_ptr = groups == nullptr ? 0 : groups->length();
*group_objs_p = objArrayHandle(current_thread, groups);
return JVMTI_ERROR_NONE;
}

5
src/hotspot/share/prims/jvmtiEnvBase.hpp
View file

@ -332,9 +332,8 @@ class JvmtiEnvBase : public CHeapObj<mtInternal> {
protected:
// helper methods for creating arrays of global JNI Handles from local Handles
// allocated into environment specific storage
jobject * new_jobjectArray(int length, Handle *handles);
jthread * new_jthreadArray(int length, Handle *handles);
jthreadGroup * new_jthreadGroupArray(int length, Handle *handles);
jthreadGroup * new_jthreadGroupArray(int length, objArrayHandle groups);
// convert to a jni jclass from a non-null Klass*
jclass get_jni_class_non_null(Klass* k);
@ -378,7 +377,7 @@ class JvmtiEnvBase : public CHeapObj<mtInternal> {
static jvmtiError get_live_threads(JavaThread* current_thread, Handle group_hdl, jint *count_ptr, Handle **thread_objs_p);
// enumerates the subgroups in the given thread group
static jvmtiError get_subgroups(JavaThread* current_thread, Handle group_hdl, jint *count_ptr, Handle **group_objs_p);
static jvmtiError get_subgroups(JavaThread* current_thread, Handle group_hdl, jint *count_ptr, objArrayHandle *group_objs_p);
// JVMTI API helper functions which are called when target thread is suspended
// or at safepoint / thread local handshake.

8
src/java.base/share/classes/java/lang/ThreadGroup.java
View file

@ -792,6 +792,14 @@ public class ThreadGroup implements Thread.UncaughtExceptionHandler {
}
}
/**
* Returns a snapshot of the subgroups as an array, used by JVMTI.
*/
private ThreadGroup[] subgroupsAsArray() {
List<ThreadGroup> groups = synchronizedSubgroups();
return groups.toArray(new ThreadGroup[0]);
}
/**
* Returns a snapshot of the subgroups.
*/