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