|
342
|
1 /*
|
|
|
2 * Copyright 2001-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
|
|
|
20 * CA 95054 USA or visit www.sun.com if you need additional information or
|
|
|
21 * have any questions.
|
|
|
22 *
|
|
|
23 */
|
|
|
24
|
|
|
25 #include "incls/_precompiled.incl"
|
|
|
26 #include "incls/_concurrentZFThread.cpp.incl"
|
|
|
27
|
|
|
28 // ======= Concurrent Zero-Fill Thread ========
|
|
|
29
|
|
|
30 // The CM thread is created when the G1 garbage collector is used
|
|
|
31
|
|
|
32 int ConcurrentZFThread::_region_allocs = 0;
|
|
|
33 int ConcurrentZFThread::_sync_zfs = 0;
|
|
|
34 int ConcurrentZFThread::_zf_waits = 0;
|
|
|
35 int ConcurrentZFThread::_regions_filled = 0;
|
|
|
36
|
|
|
37 ConcurrentZFThread::ConcurrentZFThread() :
|
|
|
38 ConcurrentGCThread(),
|
|
|
39 _co_tracker(G1ZFGroup)
|
|
|
40 {
|
|
|
41 create_and_start();
|
|
|
42 }
|
|
|
43
|
|
|
44 void ConcurrentZFThread::wait_for_ZF_completed(HeapRegion* hr) {
|
|
|
45 assert(ZF_mon->owned_by_self(), "Precondition.");
|
|
|
46 note_zf_wait();
|
|
|
47 while (hr->zero_fill_state() == HeapRegion::ZeroFilling) {
|
|
|
48 ZF_mon->wait(Mutex::_no_safepoint_check_flag);
|
|
|
49 }
|
|
|
50 }
|
|
|
51
|
|
|
52 void ConcurrentZFThread::processHeapRegion(HeapRegion* hr) {
|
|
|
53 assert(!Universe::heap()->is_gc_active(),
|
|
|
54 "This should not happen during GC.");
|
|
|
55 assert(hr != NULL, "Precondition");
|
|
|
56 // These are unlocked reads, but if this test is successful, then no
|
|
|
57 // other thread will attempt this zero filling. Only a GC thread can
|
|
|
58 // modify the ZF state of a region whose state is zero-filling, and this
|
|
|
59 // should only happen while the ZF thread is locking out GC.
|
|
|
60 if (hr->zero_fill_state() == HeapRegion::ZeroFilling
|
|
|
61 && hr->zero_filler() == Thread::current()) {
|
|
|
62 assert(hr->top() == hr->bottom(), "better be empty!");
|
|
|
63 assert(!hr->isHumongous(), "Only free regions on unclean list.");
|
|
|
64 Copy::fill_to_words(hr->bottom(), hr->capacity()/HeapWordSize);
|
|
|
65 note_region_filled();
|
|
|
66 }
|
|
|
67 }
|
|
|
68
|
|
|
69 void ConcurrentZFThread::run() {
|
|
|
70 initialize_in_thread();
|
|
|
71 Thread* thr_self = Thread::current();
|
|
|
72 _vtime_start = os::elapsedVTime();
|
|
|
73 wait_for_universe_init();
|
|
|
74 _co_tracker.enable();
|
|
|
75 _co_tracker.start();
|
|
|
76
|
|
|
77 G1CollectedHeap* g1 = G1CollectedHeap::heap();
|
|
|
78 _sts.join();
|
|
|
79 while (!_should_terminate) {
|
|
|
80 _sts.leave();
|
|
|
81
|
|
|
82 {
|
|
|
83 MutexLockerEx x(ZF_mon, Mutex::_no_safepoint_check_flag);
|
|
|
84
|
|
|
85 // This local variable will hold a region being zero-filled. This
|
|
|
86 // region will neither be on the unclean or zero-filled lists, and
|
|
|
87 // will not be available for allocation; thus, we might have an
|
|
|
88 // allocation fail, causing a full GC, because of this, but this is a
|
|
|
89 // price we will pay. (In future, we might want to make the fact
|
|
|
90 // that there's a region being zero-filled apparent to the G1 heap,
|
|
|
91 // which could then wait for it in this extreme case...)
|
|
|
92 HeapRegion* to_fill;
|
|
|
93
|
|
|
94 while (!g1->should_zf()
|
|
|
95 || (to_fill = g1->pop_unclean_region_list_locked()) == NULL)
|
|
|
96 ZF_mon->wait(Mutex::_no_safepoint_check_flag);
|
|
|
97 while (to_fill->zero_fill_state() == HeapRegion::ZeroFilling)
|
|
|
98 ZF_mon->wait(Mutex::_no_safepoint_check_flag);
|
|
|
99
|
|
|
100 // So now to_fill is non-NULL and is not ZeroFilling. It might be
|
|
|
101 // Allocated or ZeroFilled. (The latter could happen if this thread
|
|
|
102 // starts the zero-filling of a region, but a GC intervenes and
|
|
|
103 // pushes new regions needing on the front of the filling on the
|
|
|
104 // front of the list.)
|
|
|
105
|
|
|
106 switch (to_fill->zero_fill_state()) {
|
|
|
107 case HeapRegion::Allocated:
|
|
|
108 to_fill = NULL;
|
|
|
109 break;
|
|
|
110
|
|
|
111 case HeapRegion::NotZeroFilled:
|
|
|
112 to_fill->set_zero_fill_in_progress(thr_self);
|
|
|
113
|
|
|
114 ZF_mon->unlock();
|
|
|
115 _sts.join();
|
|
|
116 processHeapRegion(to_fill);
|
|
|
117 _sts.leave();
|
|
|
118 ZF_mon->lock_without_safepoint_check();
|
|
|
119
|
|
|
120 if (to_fill->zero_fill_state() == HeapRegion::ZeroFilling
|
|
|
121 && to_fill->zero_filler() == thr_self) {
|
|
|
122 to_fill->set_zero_fill_complete();
|
|
|
123 (void)g1->put_free_region_on_list_locked(to_fill);
|
|
|
124 }
|
|
|
125 break;
|
|
|
126
|
|
|
127 case HeapRegion::ZeroFilled:
|
|
|
128 (void)g1->put_free_region_on_list_locked(to_fill);
|
|
|
129 break;
|
|
|
130
|
|
|
131 case HeapRegion::ZeroFilling:
|
|
|
132 ShouldNotReachHere();
|
|
|
133 break;
|
|
|
134 }
|
|
|
135 }
|
|
|
136 _vtime_accum = (os::elapsedVTime() - _vtime_start);
|
|
|
137 _sts.join();
|
|
|
138
|
|
|
139 _co_tracker.update();
|
|
|
140 }
|
|
|
141 _co_tracker.update(false);
|
|
|
142 _sts.leave();
|
|
|
143
|
|
|
144 assert(_should_terminate, "just checking");
|
|
|
145 terminate();
|
|
|
146 }
|
|
|
147
|
|
|
148 bool ConcurrentZFThread::offer_yield() {
|
|
|
149 if (_sts.should_yield()) {
|
|
|
150 _sts.yield("Concurrent ZF");
|
|
|
151 return true;
|
|
|
152 } else {
|
|
|
153 return false;
|
|
|
154 }
|
|
|
155 }
|
|
|
156
|
|
|
157 void ConcurrentZFThread::stop() {
|
|
|
158 // it is ok to take late safepoints here, if needed
|
|
|
159 MutexLockerEx mu(Terminator_lock);
|
|
|
160 _should_terminate = true;
|
|
|
161 while (!_has_terminated) {
|
|
|
162 Terminator_lock->wait();
|
|
|
163 }
|
|
|
164 }
|
|
|
165
|
|
|
166 void ConcurrentZFThread::print() {
|
|
|
167 gclog_or_tty->print("\"Concurrent ZF Thread\" ");
|
|
|
168 Thread::print();
|
|
|
169 gclog_or_tty->cr();
|
|
|
170 }
|
|
|
171
|
|
|
172
|
|
|
173 double ConcurrentZFThread::_vtime_accum;
|
|
|
174
|
|
|
175 void ConcurrentZFThread::print_summary_info() {
|
|
|
176 gclog_or_tty->print("\nConcurrent Zero-Filling:\n");
|
|
|
177 gclog_or_tty->print(" Filled %d regions, used %5.2fs.\n",
|
|
|
178 _regions_filled,
|
|
|
179 vtime_accum());
|
|
|
180 gclog_or_tty->print(" Of %d region allocs, %d (%5.2f%%) required sync ZF,\n",
|
|
|
181 _region_allocs, _sync_zfs,
|
|
|
182 (_region_allocs > 0 ?
|
|
|
183 (float)_sync_zfs/(float)_region_allocs*100.0 :
|
|
|
184 0.0));
|
|
|
185 gclog_or_tty->print(" and %d (%5.2f%%) required a ZF wait.\n",
|
|
|
186 _zf_waits,
|
|
|
187 (_region_allocs > 0 ?
|
|
|
188 (float)_zf_waits/(float)_region_allocs*100.0 :
|
|
|
189 0.0));
|
|
|
190
|
|
|
191 }
|
