1 /* 2 * Copyright (c) 2016, 2018, 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.hpp" 38 #include "runtime/handles.hpp" 39 #include "runtime/jniHandles.inline.hpp" 40 #include "runtime/thread.inline.hpp" 41 42 static int start_pos_offset = invalid_offset; 43 static int start_pos_address_offset = invalid_offset; 44 static int current_pos_offset = invalid_offset; 45 static int max_pos_offset = invalid_offset; 46 static int max_event_size_offset = invalid_offset; 47 static int notified_offset = invalid_offset; 48 static int thread_id_offset = invalid_offset; 49 static int valid_offset = invalid_offset; 50 51 static 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 64 static 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 77 static bool setup_event_writer_offsets(TRAPS) { 78 const char class_name[] = "jdk/jfr/internal/EventWriter"; 79 Symbol* const k_sym = SymbolTable::lookup(class_name, sizeof class_name - 1, CHECK_false); 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::lookup(start_pos_name, sizeof start_pos_name - 1, CHECK_false); 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::lookup(start_pos_address_name, sizeof start_pos_address_name - 1, CHECK_false); 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::lookup(event_pos_name, sizeof event_pos_name - 1, CHECK_false); 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::lookup(max_pos_name, sizeof max_pos_name - 1, CHECK_false); 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::lookup(max_event_size_name, sizeof max_event_size_name - 1, CHECK_false); 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::lookup(notified_name, sizeof notified_name - 1, CHECK_false); 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::lookup(valid_name, sizeof valid_name - 1, CHECK_false); 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 } 134 135 bool JfrJavaEventWriter::initialize() { 136 static bool initialized = false; 137 if (!initialized) { 138 Thread* thread = Thread::current(); 139 initialized = setup_event_writer_offsets(thread); 140 } 141 return initialized; 142 } 143 144 jboolean JfrJavaEventWriter::flush(jobject writer, jint used, jint requested, JavaThread* jt) { 145 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(jt)); 146 assert(writer != NULL, "invariant"); 147 oop const w = JNIHandles::resolve_non_null(writer); 148 assert(w != NULL, "invariant"); 149 JfrBuffer* const current = jt->jfr_thread_local()->java_buffer(); 150 assert(current != NULL, "invariant"); 151 JfrBuffer* const buffer = JfrStorage::flush(current, used, requested, false, jt); 152 assert(buffer != NULL, "invariant"); 153 // "validity" is contextually defined here to mean 154 // that some memory location was provided that is 155 // large enough to accommodate the "requested size". 156 const bool is_valid = buffer->free_size() >= (size_t)(used + requested); 157 u1* const new_current_position = is_valid ? buffer->pos() + used : buffer->pos(); 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 } 176 177 class 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 }; 185 186 void JfrJavaEventWriter::notify() { 187 assert(SafepointSynchronize::is_at_safepoint(), "invariant"); 188 JfrJavaEventWriterNotificationClosure closure; 189 Threads::threads_do(&closure); 190 } 191 192 void 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 } 201 202 static 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 } 220 221 jobject 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 } 227 228 jobject 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 }