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/*
* Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
#include "precompiled.hpp"
#include "jni.h"
#include "classfile/symbolTable.hpp"
#include "classfile/systemDictionary.hpp"
#include "classfile/vmSymbols.hpp"
#include "jfr/jni/jfrJavaSupport.hpp"
#include "jfr/recorder/storage/jfrStorage.hpp"
#include "jfr/support/jfrThreadId.hpp"
#include "jfr/utilities/jfrTypes.hpp"
#include "jfr/writers/jfrJavaEventWriter.hpp"
#include "memory/iterator.hpp"
#include "oops/instanceKlass.hpp"
#include "oops/oop.inline.hpp"
#include "runtime/fieldDescriptor.inline.hpp"
#include "runtime/handles.hpp"
#include "runtime/jniHandles.inline.hpp"
#include "runtime/thread.inline.hpp"
static int start_pos_offset = invalid_offset;
static int start_pos_address_offset = invalid_offset;
static int current_pos_offset = invalid_offset;
static int max_pos_offset = invalid_offset;
static int max_event_size_offset = invalid_offset;
static int notified_offset = invalid_offset;
static int thread_id_offset = invalid_offset;
static int valid_offset = invalid_offset;
static bool find_field(InstanceKlass* ik,
Symbol* name_symbol,
Symbol* signature_symbol,
fieldDescriptor* fd,
bool is_static = false,
bool allow_super = false) {
if (allow_super || is_static) {
return ik->find_field(name_symbol, signature_symbol, is_static, fd) != NULL;
} else {
return ik->find_local_field(name_symbol, signature_symbol, fd);
}
}
static void compute_offset(int &dest_offset,
Klass* klass,
Symbol* name_symbol,
Symbol* signature_symbol,
bool is_static = false, bool allow_super = false) {
fieldDescriptor fd;
InstanceKlass* ik = InstanceKlass::cast(klass);
if (!find_field(ik, name_symbol, signature_symbol, &fd, is_static, allow_super)) {
assert(false, "invariant");
}
dest_offset = fd.offset();
}
static bool setup_event_writer_offsets(TRAPS) {
const char class_name[] = "jdk/jfr/internal/EventWriter";
Symbol* const k_sym = SymbolTable::lookup(class_name, sizeof class_name - 1, CHECK_false);
assert(k_sym != NULL, "invariant");
Klass* klass = SystemDictionary::resolve_or_fail(k_sym, true, CHECK_false);
assert(klass != NULL, "invariant");
const char start_pos_name[] = "startPosition";
Symbol* const start_pos_sym = SymbolTable::lookup(start_pos_name, sizeof start_pos_name - 1, CHECK_false);
assert(start_pos_sym != NULL, "invariant");
assert(invalid_offset == start_pos_offset, "invariant");
compute_offset(start_pos_offset, klass, start_pos_sym, vmSymbols::long_signature());
assert(start_pos_offset != invalid_offset, "invariant");
const char start_pos_address_name[] = "startPositionAddress";
Symbol* const start_pos_address_sym = SymbolTable::lookup(start_pos_address_name, sizeof start_pos_address_name - 1, CHECK_false);
assert(start_pos_address_sym != NULL, "invariant");
assert(invalid_offset == start_pos_address_offset, "invariant");
compute_offset(start_pos_address_offset, klass, start_pos_address_sym, vmSymbols::long_signature());
assert(start_pos_address_offset != invalid_offset, "invariant");
const char event_pos_name[] = "currentPosition";
Symbol* const event_pos_sym = SymbolTable::lookup(event_pos_name, sizeof event_pos_name - 1, CHECK_false);
assert(event_pos_sym != NULL, "invariant");
assert(invalid_offset == current_pos_offset, "invariant");
compute_offset(current_pos_offset, klass, event_pos_sym,vmSymbols::long_signature());
assert(current_pos_offset != invalid_offset, "invariant");
const char max_pos_name[] = "maxPosition";
Symbol* const max_pos_sym = SymbolTable::lookup(max_pos_name, sizeof max_pos_name - 1, CHECK_false);
assert(max_pos_sym != NULL, "invariant");
assert(invalid_offset == max_pos_offset, "invariant");
compute_offset(max_pos_offset, klass, max_pos_sym, vmSymbols::long_signature());
assert(max_pos_offset != invalid_offset, "invariant");
const char max_event_size_name[] = "maxEventSize";
Symbol* const max_event_size_sym = SymbolTable::lookup(max_event_size_name, sizeof max_event_size_name - 1, CHECK_false);
assert (max_event_size_sym != NULL, "invariant");
assert(invalid_offset == max_event_size_offset, "invariant");
compute_offset(max_event_size_offset, klass, max_event_size_sym, vmSymbols::int_signature());
assert(max_event_size_offset != invalid_offset, "invariant");
const char notified_name[] = "notified";
Symbol* const notified_sym = SymbolTable::lookup(notified_name, sizeof notified_name - 1, CHECK_false);
assert (notified_sym != NULL, "invariant");
assert(invalid_offset == notified_offset, "invariant");
compute_offset(notified_offset, klass, notified_sym, vmSymbols::bool_signature());
assert(notified_offset != invalid_offset, "invariant");
const char valid_name[] = "valid";
Symbol* const valid_sym = SymbolTable::lookup(valid_name, sizeof valid_name - 1, CHECK_false);
assert (valid_sym != NULL, "invariant");
assert(invalid_offset == valid_offset, "invariant");
compute_offset(valid_offset, klass, valid_sym, vmSymbols::bool_signature());
assert(valid_offset != invalid_offset, "invariant");
return true;
}
bool JfrJavaEventWriter::initialize() {
static bool initialized = false;
if (!initialized) {
initialized = setup_event_writer_offsets(Thread::current());
}
return initialized;
}
jboolean JfrJavaEventWriter::flush(jobject writer, jint used, jint requested, JavaThread* jt) {
DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(jt));
assert(writer != NULL, "invariant");
oop const w = JNIHandles::resolve_non_null(writer);
assert(w != NULL, "invariant");
JfrBuffer* const current = jt->jfr_thread_local()->java_buffer();
assert(current != NULL, "invariant");
JfrBuffer* const buffer = JfrStorage::flush(current, used, requested, false, jt);
assert(buffer != NULL, "invariant");
// "validity" is contextually defined here to mean
// that some memory location was provided that is
// large enough to accommodate the "requested size".
const bool is_valid = buffer->free_size() >= (size_t)(used + requested);
u1* const new_current_position = is_valid ? buffer->pos() + used : buffer->pos();
assert(start_pos_offset != invalid_offset, "invariant");
w->long_field_put(start_pos_offset, (jlong)buffer->pos());
w->long_field_put(current_pos_offset, (jlong)new_current_position);
// only update java writer if underlying memory changed
if (buffer != current) {
w->long_field_put(start_pos_address_offset, (jlong)buffer->pos_address());
w->long_field_put(max_pos_offset, (jlong)buffer->end());
}
if (!is_valid) {
// mark writer as invalid for this write attempt
w->release_bool_field_put(valid_offset, JNI_FALSE);
return JNI_FALSE;
}
// An exclusive use of a leased buffer is treated equivalent to
// holding a system resource. As such, it should be released as soon as possible.
// Returning true here signals that the thread will need to call flush again
// on EventWriter.endEvent() and that flush will return the lease.
return buffer->lease() ? JNI_TRUE : JNI_FALSE;
}
class JfrJavaEventWriterNotificationClosure : public ThreadClosure {
public:
void do_thread(Thread* t) {
if (t->is_Java_thread()) {
JfrJavaEventWriter::notify((JavaThread*)t);
}
}
};
void JfrJavaEventWriter::notify() {
assert(SafepointSynchronize::is_at_safepoint(), "invariant");
JfrJavaEventWriterNotificationClosure closure;
Threads::threads_do(&closure);
}
void JfrJavaEventWriter::notify(JavaThread* jt) {
assert(jt != NULL, "invariant");
assert(SafepointSynchronize::is_at_safepoint(), "invariant");
if (jt->jfr_thread_local()->has_java_event_writer()) {
oop buffer_writer = JNIHandles::resolve_non_null(jt->jfr_thread_local()->java_event_writer());
assert(buffer_writer != NULL, "invariant");
buffer_writer->release_bool_field_put(notified_offset, JNI_TRUE);
}
}
static jobject create_new_event_writer(JfrBuffer* buffer, TRAPS) {
assert(buffer != NULL, "invariant");
DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(THREAD));
HandleMark hm(THREAD);
static const char klass[] = "jdk/jfr/internal/EventWriter";
static const char method[] = "<init>";
static const char signature[] = "(JJJJZ)V";
JavaValue result(T_OBJECT);
JfrJavaArguments args(&result, klass, method, signature, CHECK_NULL);
// parameters
args.push_long((jlong)buffer->pos());
args.push_long((jlong)buffer->end());
args.push_long((jlong)buffer->pos_address());
args.push_long((jlong)JFR_THREAD_ID(THREAD));
args.push_int((int)JNI_TRUE);
JfrJavaSupport::new_object_global_ref(&args, CHECK_NULL);
return result.get_jobject();
}
jobject JfrJavaEventWriter::event_writer(Thread* t) {
DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(t));
JfrThreadLocal* const tl = t->jfr_thread_local();
assert(tl->shelved_buffer() == NULL, "invariant");
return tl->java_event_writer();
}
jobject JfrJavaEventWriter::new_event_writer(TRAPS) {
DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(THREAD));
assert(event_writer(THREAD) == NULL, "invariant");
JfrThreadLocal* const tl = THREAD->jfr_thread_local();
assert(!tl->has_java_buffer(), "invariant");
JfrBuffer* const buffer = tl->java_buffer();
if (buffer == NULL) {
JfrJavaSupport::throw_out_of_memory_error("OOME for thread local buffer", THREAD);
return NULL;
}
jobject java_event_writer = create_new_event_writer(buffer, CHECK_NULL);
tl->set_java_event_writer(java_event_writer);
assert(tl->has_java_event_writer(), "invariant");
return java_event_writer;
}