1 /* 2 * Copyright (c) 2002, 2015, 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 "gc/parallel/gcTaskManager.hpp" 27 #include "gc/parallel/gcTaskThread.hpp" 28 #include "gc/shared/gcId.hpp" 29 #include "logging/log.hpp" 30 #include "memory/allocation.hpp" 31 #include "memory/allocation.inline.hpp" 32 #include "memory/resourceArea.hpp" 33 #include "runtime/atomic.inline.hpp" 34 #include "runtime/handles.hpp" 35 #include "runtime/handles.inline.hpp" 36 #include "runtime/os.hpp" 37 #include "runtime/thread.hpp" 38 39 GCTaskThread::GCTaskThread(GCTaskManager* manager, 40 uint which, 41 uint processor_id) : 42 _manager(manager), 43 _processor_id(processor_id), 44 _time_stamps(NULL), 45 _time_stamp_index(0) 46 { 47 if (!os::create_thread(this, os::pgc_thread)) 48 vm_exit_out_of_memory(0, OOM_MALLOC_ERROR, "Cannot create GC thread. Out of system resources."); 49 50 set_id(which); 51 set_name("ParGC Thread#%d", which); 52 } 53 54 GCTaskThread::~GCTaskThread() { 55 if (_time_stamps != NULL) { 56 FREE_C_HEAP_ARRAY(GCTaskTimeStamp, _time_stamps); 57 } 58 } 59 60 void GCTaskThread::start() { 61 os::start_thread(this); 62 } 63 64 GCTaskTimeStamp* GCTaskThread::time_stamp_at(uint index) { 65 guarantee(index < GCTaskTimeStampEntries, "increase GCTaskTimeStampEntries"); 66 if (_time_stamps == NULL) { 67 // We allocate the _time_stamps array lazily since logging can be enabled dynamically 68 GCTaskTimeStamp* time_stamps = NEW_C_HEAP_ARRAY(GCTaskTimeStamp, GCTaskTimeStampEntries, mtGC); 69 void* old = Atomic::cmpxchg_ptr(time_stamps, &_time_stamps, NULL); 70 if (old != NULL) { 71 // Someone already setup the time stamps 72 FREE_C_HEAP_ARRAY(GCTaskTimeStamp, time_stamps); 73 } 74 } 75 76 return &(_time_stamps[index]); 77 } 78 79 void GCTaskThread::print_task_time_stamps() { 80 assert(log_is_enabled(Debug, gc, task, time), "Sanity"); 81 assert(_time_stamps != NULL, "Sanity"); 82 83 log_debug(gc, task, time)("GC-Thread %u entries: %d", id(), _time_stamp_index); 84 for(uint i=0; i<_time_stamp_index; i++) { 85 GCTaskTimeStamp* time_stamp = time_stamp_at(i); 86 log_debug(gc, task, time)("\t[ %s " JLONG_FORMAT " " JLONG_FORMAT " ]", 87 time_stamp->name(), 88 time_stamp->entry_time(), 89 time_stamp->exit_time()); 90 } 91 92 // Reset after dumping the data 93 _time_stamp_index = 0; 94 } 95 96 // GC workers get tasks from the GCTaskManager and execute 97 // them in this method. If there are no tasks to execute, 98 // the GC workers wait in the GCTaskManager's get_task() 99 // for tasks to be enqueued for execution. 100 101 void GCTaskThread::run() { 102 // Set up the thread for stack overflow support 103 this->record_stack_base_and_size(); 104 this->initialize_named_thread(); 105 // Bind yourself to your processor. 106 if (processor_id() != GCTaskManager::sentinel_worker()) { 107 if (TraceGCTaskThread) { 108 tty->print_cr("GCTaskThread::run: " 109 " binding to processor %u", processor_id()); 110 } 111 if (!os::bind_to_processor(processor_id())) { 112 DEBUG_ONLY( 113 warning("Couldn't bind GCTaskThread %u to processor %u", 114 which(), processor_id()); 115 ) 116 } 117 } 118 // Part of thread setup. 119 // ??? Are these set up once here to make subsequent ones fast? 120 HandleMark hm_outer; 121 ResourceMark rm_outer; 122 123 TimeStamp timer; 124 125 for (;/* ever */;) { 126 // These are so we can flush the resources allocated in the inner loop. 127 HandleMark hm_inner; 128 ResourceMark rm_inner; 129 for (; /* break */; ) { 130 // This will block until there is a task to be gotten. 131 GCTask* task = manager()->get_task(which()); 132 GCIdMark gc_id_mark(task->gc_id()); 133 // Record if this is an idle task for later use. 134 bool is_idle_task = task->is_idle_task(); 135 // In case the update is costly 136 if (log_is_enabled(Debug, gc, task, time)) { 137 timer.update(); 138 } 139 140 jlong entry_time = timer.ticks(); 141 char* name = task->name(); 142 143 // If this is the barrier task, it can be destroyed 144 // by the GC task manager once the do_it() executes. 145 task->do_it(manager(), which()); 146 147 // Use the saved value of is_idle_task because references 148 // using "task" are not reliable for the barrier task. 149 if (!is_idle_task) { 150 manager()->note_completion(which()); 151 152 if (log_is_enabled(Debug, gc, task, time)) { 153 timer.update(); 154 155 GCTaskTimeStamp* time_stamp = time_stamp_at(_time_stamp_index); 156 157 time_stamp->set_name(name); 158 time_stamp->set_entry_time(entry_time); 159 time_stamp->set_exit_time(timer.ticks()); 160 161 // Update the index after we have set up the entry correctly since 162 // GCTaskThread::print_task_time_stamps() may read this value concurrently. 163 _time_stamp_index++; 164 } 165 } else { 166 // idle tasks complete outside the normal accounting 167 // so that a task can complete without waiting for idle tasks. 168 // They have to be terminated separately. 169 IdleGCTask::destroy((IdleGCTask*)task); 170 set_is_working(true); 171 } 172 173 // Check if we should release our inner resources. 174 if (manager()->should_release_resources(which())) { 175 manager()->note_release(which()); 176 break; 177 } 178 } 179 } 180 }