1
2 /*
3 * Copyright (c) 2002, 2015, Oracle and/or its affiliates. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "precompiled.hpp"
27 #include "gc/parallel/gcTaskManager.hpp"
28 #include "gc/parallel/gcTaskThread.hpp"
29 #include "gc/shared/gcId.hpp"
30 #include "logging/log.hpp"
31 #include "memory/allocation.hpp"
32 #include "memory/allocation.inline.hpp"
33 #include "memory/resourceArea.hpp"
34 #include "runtime/atomic.inline.hpp"
35 #include "runtime/handles.hpp"
36 #include "runtime/handles.inline.hpp"
37 #include "runtime/os.hpp"
38 #include "runtime/thread.hpp"
39
40 GCTaskThread::GCTaskThread(GCTaskManager* manager,
41 uint which,
42 uint processor_id) :
43 _manager(manager),
44 _processor_id(processor_id),
45 _time_stamps(NULL),
46 _time_stamp_index(0)
47 {
48 if (!os::create_thread(this, os::pgc_thread))
49 vm_exit_out_of_memory(0, OOM_MALLOC_ERROR, "Cannot create GC thread. Out of system resources.");
50
51 set_id(which);
52 set_name("ParGC Thread#%d", which);
53 }
54
55 GCTaskThread::~GCTaskThread() {
56 if (_time_stamps != NULL) {
57 FREE_C_HEAP_ARRAY(GCTaskTimeStamp, _time_stamps);
58 }
59 }
60
61 void GCTaskThread::start() {
62 os::start_thread(this);
63 }
64
65 GCTaskTimeStamp* GCTaskThread::time_stamp_at(uint index) {
66 guarantee(index < GCTaskTimeStampEntries, "increase GCTaskTimeStampEntries");
67 if (_time_stamps == NULL) {
68 // We allocate the _time_stamps array lazily since logging can be enabled dynamically
69 GCTaskTimeStamp* time_stamps = NEW_C_HEAP_ARRAY(GCTaskTimeStamp, GCTaskTimeStampEntries, mtGC);
70 void* old = Atomic::cmpxchg_ptr(time_stamps, &_time_stamps, NULL);
71 if (old != NULL) {
72 // Someone already setup the time stamps
73 FREE_C_HEAP_ARRAY(GCTaskTimeStamp, time_stamps);
74 }
75 }
76
77 return &(_time_stamps[index]);
78 }
79
80 void GCTaskThread::print_task_time_stamps() {
81 assert((Log<LOG_TAGS(gc, task, time)>::is_debug()), "Sanity");
82 assert(_time_stamps != NULL, "Sanity");
83
84 log_debug(gc, task, time)("GC-Thread %u entries: %d", id(), _time_stamp_index);
85 for(uint i=0; i<_time_stamp_index; i++) {
86 GCTaskTimeStamp* time_stamp = time_stamp_at(i);
87 log_debug(gc, task, time)("\t[ %s " JLONG_FORMAT " " JLONG_FORMAT " ]",
88 time_stamp->name(),
89 time_stamp->entry_time(),
90 time_stamp->exit_time());
91 }
92
93 // Reset after dumping the data
94 _time_stamp_index = 0;
95 }
96
97 // GC workers get tasks from the GCTaskManager and execute
98 // them in this method. If there are no tasks to execute,
99 // the GC workers wait in the GCTaskManager's get_task()
100 // for tasks to be enqueued for execution.
101
102 void GCTaskThread::run() {
103 // Set up the thread for stack overflow support
104 this->record_stack_base_and_size();
105 this->initialize_thread_local_storage();
106 this->initialize_named_thread();
107 // Bind yourself to your processor.
108 if (processor_id() != GCTaskManager::sentinel_worker()) {
109 if (TraceGCTaskThread) {
110 tty->print_cr("GCTaskThread::run: "
111 " binding to processor %u", processor_id());
112 }
113 if (!os::bind_to_processor(processor_id())) {
114 DEBUG_ONLY(
115 warning("Couldn't bind GCTaskThread %u to processor %u",
116 which(), processor_id());
117 )
118 }
119 }
120 // Part of thread setup.
121 // ??? Are these set up once here to make subsequent ones fast?
122 HandleMark hm_outer;
123 ResourceMark rm_outer;
124
125 TimeStamp timer;
126
127 for (;/* ever */;) {
128 // These are so we can flush the resources allocated in the inner loop.
129 HandleMark hm_inner;
130 ResourceMark rm_inner;
131 for (; /* break */; ) {
132 // This will block until there is a task to be gotten.
133 GCTask* task = manager()->get_task(which());
134 GCIdMark gc_id_mark(task->gc_id());
135 // Record if this is an idle task for later use.
136 bool is_idle_task = task->is_idle_task();
137 // In case the update is costly
138 if (Log<LOG_TAGS(gc, task, time)>::is_debug()) {
139 timer.update();
140 }
141
142 jlong entry_time = timer.ticks();
143 char* name = task->name();
144
145 // If this is the barrier task, it can be destroyed
146 // by the GC task manager once the do_it() executes.
147 task->do_it(manager(), which());
148
149 // Use the saved value of is_idle_task because references
150 // using "task" are not reliable for the barrier task.
151 if (!is_idle_task) {
152 manager()->note_completion(which());
153
154 if (Log<LOG_TAGS(gc, task, time)>::is_debug()) {
155 timer.update();
156
157 GCTaskTimeStamp* time_stamp = time_stamp_at(_time_stamp_index++);
158
159 time_stamp->set_name(name);
160 time_stamp->set_entry_time(entry_time);
161 time_stamp->set_exit_time(timer.ticks());
162 }
163 } else {
164 // idle tasks complete outside the normal accounting
165 // so that a task can complete without waiting for idle tasks.
166 // They have to be terminated separately.
167 IdleGCTask::destroy((IdleGCTask*)task);
168 set_is_working(true);
169 }
170
171 // Check if we should release our inner resources.
172 if (manager()->should_release_resources(which())) {
173 manager()->note_release(which());
174 break;
175 }
176 }
177 }
178 }