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
82 // Since _time_stamps is now lazily allocated we need to check that it
83 // has in fact been allocated when calling this function.
84 if (_time_stamps != NULL) {
85 log_debug(gc, task, time)("GC-Thread %u entries: %d", id(), _time_stamp_index);
86 for(uint i=0; i<_time_stamp_index; i++) {
87 GCTaskTimeStamp* time_stamp = time_stamp_at(i);
88 log_debug(gc, task, time)("\t[ %s " JLONG_FORMAT " " JLONG_FORMAT " ]",
89 time_stamp->name(),
90 time_stamp->entry_time(),
91 time_stamp->exit_time());
92 }
93
94 // Reset after dumping the data
95 _time_stamp_index = 0;
96 }
97 }
98
99 // GC workers get tasks from the GCTaskManager and execute
100 // them in this method. If there are no tasks to execute,
101 // the GC workers wait in the GCTaskManager's get_task()
102 // for tasks to be enqueued for execution.
103
104 void GCTaskThread::run() {
105 // Set up the thread for stack overflow support
106 this->record_stack_base_and_size();
107 this->initialize_named_thread();
108 // Bind yourself to your processor.
109 if (processor_id() != GCTaskManager::sentinel_worker()) {
110 if (TraceGCTaskThread) {
111 tty->print_cr("GCTaskThread::run: "
112 " binding to processor %u", processor_id());
113 }
114 if (!os::bind_to_processor(processor_id())) {
115 DEBUG_ONLY(
116 warning("Couldn't bind GCTaskThread %u to processor %u",
117 which(), processor_id());
118 )
119 }
120 }
121 // Part of thread setup.
122 // ??? Are these set up once here to make subsequent ones fast?
123 HandleMark hm_outer;
124 ResourceMark rm_outer;
125
126 TimeStamp timer;
127
128 for (;/* ever */;) {
129 // These are so we can flush the resources allocated in the inner loop.
130 HandleMark hm_inner;
131 ResourceMark rm_inner;
132 for (; /* break */; ) {
133 // This will block until there is a task to be gotten.
134 GCTask* task = manager()->get_task(which());
135 GCIdMark gc_id_mark(task->gc_id());
136 // Record if this is an idle task for later use.
137 bool is_idle_task = task->is_idle_task();
138 // In case the update is costly
139 if (log_is_enabled(Debug, gc, task, time)) {
140 timer.update();
141 }
142
143 jlong entry_time = timer.ticks();
144 char* name = task->name();
145
146 // If this is the barrier task, it can be destroyed
147 // by the GC task manager once the do_it() executes.
148 task->do_it(manager(), which());
149
150 // Use the saved value of is_idle_task because references
151 // using "task" are not reliable for the barrier task.
152 if (!is_idle_task) {
153 manager()->note_completion(which());
154
155 if (log_is_enabled(Debug, gc, task, time)) {
156 timer.update();
157
158 GCTaskTimeStamp* time_stamp = time_stamp_at(_time_stamp_index);
159
160 time_stamp->set_name(name);
161 time_stamp->set_entry_time(entry_time);
162 time_stamp->set_exit_time(timer.ticks());
163
164 // Update the index after we have set up the entry correctly since
165 // GCTaskThread::print_task_time_stamps() may read this value concurrently.
166 _time_stamp_index++;
167 }
168 } else {
169 // idle tasks complete outside the normal accounting
170 // so that a task can complete without waiting for idle tasks.
171 // They have to be terminated separately.
172 IdleGCTask::destroy((IdleGCTask*)task);
173 set_is_working(true);
174 }
175
176 // Check if we should release our inner resources.
177 if (manager()->should_release_resources(which())) {
178 manager()->note_release(which());
179 break;
180 }
181 }
182 }
183 }