1/*
2 * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25#include "precompiled.hpp"
26#include "jni.h"
27#include "classfile/symbolTable.hpp"
28#include "classfile/systemDictionary.hpp"
29#include "classfile/vmSymbols.hpp"
30#include "jfr/jni/jfrJavaSupport.hpp"
31#include "jfr/recorder/storage/jfrStorage.hpp"
32#include "jfr/support/jfrThreadId.hpp"
33#include "jfr/utilities/jfrTypes.hpp"
34#include "jfr/writers/jfrJavaEventWriter.hpp"
35#include "oops/instanceKlass.hpp"
36#include "oops/oop.inline.hpp"
37#include "runtime/fieldDescriptor.inline.hpp"
38#include "runtime/handles.inline.hpp"
39#include "runtime/jniHandles.inline.hpp"
40#include "runtime/thread.inline.hpp"
41
42static int start_pos_offset = invalid_offset;
43static int start_pos_address_offset = invalid_offset;
44static int current_pos_offset = invalid_offset;
45static int max_pos_offset = invalid_offset;
46static int max_event_size_offset = invalid_offset;
47static int notified_offset = invalid_offset;
48static int thread_id_offset = invalid_offset;
49static int valid_offset = invalid_offset;
50
51static bool find_field(InstanceKlass* ik,
52 Symbol* name_symbol,
53 Symbol* signature_symbol,
54 fieldDescriptor* fd,
55 bool is_static = false,
56 bool allow_super = false) {
57 if (allow_super || is_static) {
58 return ik->find_field(name_symbol, signature_symbol, is_static, fd) != NULL;
59 } else {
60 return ik->find_local_field(name_symbol, signature_symbol, fd);
61 }
62}
63
64static void compute_offset(int &dest_offset,
65 Klass* klass,
66 Symbol* name_symbol,
67 Symbol* signature_symbol,
68 bool is_static = false, bool allow_super = false) {
69 fieldDescriptor fd;
70 InstanceKlass* ik = InstanceKlass::cast(klass);
71 if (!find_field(ik, name_symbol, signature_symbol, &fd, is_static, allow_super)) {
72 assert(false, "invariant");
73 }
74 dest_offset = fd.offset();
75}
76
77static bool setup_event_writer_offsets(TRAPS) {
78 const char class_name[] = "jdk/jfr/internal/EventWriter";
79 Symbol* const k_sym = SymbolTable::new_symbol(class_name);
80 assert(k_sym != NULL, "invariant");
81 Klass* klass = SystemDictionary::resolve_or_fail(k_sym, true, CHECK_false);
82 assert(klass != NULL, "invariant");
83
84 const char start_pos_name[] = "startPosition";
85 Symbol* const start_pos_sym = SymbolTable::new_symbol(start_pos_name);
86 assert(start_pos_sym != NULL, "invariant");
87 assert(invalid_offset == start_pos_offset, "invariant");
88 compute_offset(start_pos_offset, klass, start_pos_sym, vmSymbols::long_signature());
89 assert(start_pos_offset != invalid_offset, "invariant");
90
91 const char start_pos_address_name[] = "startPositionAddress";
92 Symbol* const start_pos_address_sym = SymbolTable::new_symbol(start_pos_address_name);
93 assert(start_pos_address_sym != NULL, "invariant");
94 assert(invalid_offset == start_pos_address_offset, "invariant");
95 compute_offset(start_pos_address_offset, klass, start_pos_address_sym, vmSymbols::long_signature());
96 assert(start_pos_address_offset != invalid_offset, "invariant");
97
98 const char event_pos_name[] = "currentPosition";
99 Symbol* const event_pos_sym = SymbolTable::new_symbol(event_pos_name);
100 assert(event_pos_sym != NULL, "invariant");
101 assert(invalid_offset == current_pos_offset, "invariant");
102 compute_offset(current_pos_offset, klass, event_pos_sym,vmSymbols::long_signature());
103 assert(current_pos_offset != invalid_offset, "invariant");
104
105 const char max_pos_name[] = "maxPosition";
106 Symbol* const max_pos_sym = SymbolTable::new_symbol(max_pos_name);
107 assert(max_pos_sym != NULL, "invariant");
108 assert(invalid_offset == max_pos_offset, "invariant");
109 compute_offset(max_pos_offset, klass, max_pos_sym, vmSymbols::long_signature());
110 assert(max_pos_offset != invalid_offset, "invariant");
111
112 const char max_event_size_name[] = "maxEventSize";
113 Symbol* const max_event_size_sym = SymbolTable::new_symbol(max_event_size_name);
114 assert (max_event_size_sym != NULL, "invariant");
115 assert(invalid_offset == max_event_size_offset, "invariant");
116 compute_offset(max_event_size_offset, klass, max_event_size_sym, vmSymbols::int_signature());
117 assert(max_event_size_offset != invalid_offset, "invariant");
118
119 const char notified_name[] = "notified";
120 Symbol* const notified_sym = SymbolTable::new_symbol(notified_name);
121 assert (notified_sym != NULL, "invariant");
122 assert(invalid_offset == notified_offset, "invariant");
123 compute_offset(notified_offset, klass, notified_sym, vmSymbols::bool_signature());
124 assert(notified_offset != invalid_offset, "invariant");
125
126 const char valid_name[] = "valid";
127 Symbol* const valid_sym = SymbolTable::new_symbol(valid_name);
128 assert (valid_sym != NULL, "invariant");
129 assert(invalid_offset == valid_offset, "invariant");
130 compute_offset(valid_offset, klass, valid_sym, vmSymbols::bool_signature());
131 assert(valid_offset != invalid_offset, "invariant");
132 return true;
133}
134
135bool JfrJavaEventWriter::initialize() {
136 static bool initialized = false;
137 if (!initialized) {
138 initialized = setup_event_writer_offsets(Thread::current());
139 }
140 return initialized;
141}
142
143jboolean JfrJavaEventWriter::flush(jobject writer, jint used, jint requested, JavaThread* jt) {
144 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(jt));
145 assert(writer != NULL, "invariant");
146 oop const w = JNIHandles::resolve_non_null(writer);
147 assert(w != NULL, "invariant");
148 JfrBuffer* const current = jt->jfr_thread_local()->java_buffer();
149 assert(current != NULL, "invariant");
150 JfrBuffer* const buffer = JfrStorage::flush(current, used, requested, false, jt);
151 assert(buffer != NULL, "invariant");
152 // "validity" is contextually defined here to mean
153 // that some memory location was provided that is
154 // large enough to accommodate the "requested size".
155 const bool is_valid = buffer->free_size() >= (size_t)(used + requested);
156 u1* const new_current_position = is_valid ? buffer->pos() + used : buffer->pos();
157 assert(start_pos_offset != invalid_offset, "invariant");
158 w->long_field_put(start_pos_offset, (jlong)buffer->pos());
159 w->long_field_put(current_pos_offset, (jlong)new_current_position);
160 // only update java writer if underlying memory changed
161 if (buffer != current) {
162 w->long_field_put(start_pos_address_offset, (jlong)buffer->pos_address());
163 w->long_field_put(max_pos_offset, (jlong)buffer->end());
164 }
165 if (!is_valid) {
166 // mark writer as invalid for this write attempt
167 w->release_bool_field_put(valid_offset, JNI_FALSE);
168 return JNI_FALSE;
169 }
170 // An exclusive use of a leased buffer is treated equivalent to
171 // holding a system resource. As such, it should be released as soon as possible.
172 // Returning true here signals that the thread will need to call flush again
173 // on EventWriter.endEvent() and that flush will return the lease.
174 return buffer->lease() ? JNI_TRUE : JNI_FALSE;
175}
176
177class JfrJavaEventWriterNotificationClosure : public ThreadClosure {
178 public:
179 void do_thread(Thread* t) {
180 if (t->is_Java_thread()) {
181 JfrJavaEventWriter::notify((JavaThread*)t);
182 }
183 }
184};
185
186void JfrJavaEventWriter::notify() {
187 assert(SafepointSynchronize::is_at_safepoint(), "invariant");
188 JfrJavaEventWriterNotificationClosure closure;
189 Threads::threads_do(&closure);
190}
191
192void JfrJavaEventWriter::notify(JavaThread* jt) {
193 assert(jt != NULL, "invariant");
194 assert(SafepointSynchronize::is_at_safepoint(), "invariant");
195 if (jt->jfr_thread_local()->has_java_event_writer()) {
196 oop buffer_writer = JNIHandles::resolve_non_null(jt->jfr_thread_local()->java_event_writer());
197 assert(buffer_writer != NULL, "invariant");
198 buffer_writer->release_bool_field_put(notified_offset, JNI_TRUE);
199 }
200}
201
202static jobject create_new_event_writer(JfrBuffer* buffer, TRAPS) {
203 assert(buffer != NULL, "invariant");
204 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(THREAD));
205 HandleMark hm(THREAD);
206 static const char klass[] = "jdk/jfr/internal/EventWriter";
207 static const char method[] = "<init>";
208 static const char signature[] = "(JJJJZ)V";
209 JavaValue result(T_OBJECT);
210 JfrJavaArguments args(&result, klass, method, signature, CHECK_NULL);
211 // parameters
212 args.push_long((jlong)buffer->pos());
213 args.push_long((jlong)buffer->end());
214 args.push_long((jlong)buffer->pos_address());
215 args.push_long((jlong)JFR_THREAD_ID(THREAD));
216 args.push_int((int)JNI_TRUE);
217 JfrJavaSupport::new_object_global_ref(&args, CHECK_NULL);
218 return result.get_jobject();
219}
220
221jobject JfrJavaEventWriter::event_writer(Thread* t) {
222 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(t));
223 JfrThreadLocal* const tl = t->jfr_thread_local();
224 assert(tl->shelved_buffer() == NULL, "invariant");
225 return tl->java_event_writer();
226}
227
228jobject JfrJavaEventWriter::new_event_writer(TRAPS) {
229 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(THREAD));
230 assert(event_writer(THREAD) == NULL, "invariant");
231 JfrThreadLocal* const tl = THREAD->jfr_thread_local();
232 assert(!tl->has_java_buffer(), "invariant");
233 JfrBuffer* const buffer = tl->java_buffer();
234 if (buffer == NULL) {
235 JfrJavaSupport::throw_out_of_memory_error("OOME for thread local buffer", THREAD);
236 return NULL;
237 }
238 jobject java_event_writer = create_new_event_writer(buffer, CHECK_NULL);
239 tl->set_java_event_writer(java_event_writer);
240 assert(tl->has_java_event_writer(), "invariant");
241 return java_event_writer;
242}
243