Mercurial > hg > graal-compiler
annotate src/share/vm/memory/gcLocker.cpp @ 4712:e7dead7e90af
7117303: VM uses non-monotonic time source and complains that it is non-monotonic
Summary: Replaces calls to os::javaTimeMillis(), which does not (and cannot) guarantee monotonicity, in GC code to an equivalent expression that uses os::javaTimeNanos(). os::javaTimeNanos is guaranteed monotonically non-decreasing if the underlying platform provides a monotonic time source. Changes in OS files are to make use of the newly defined constants in globalDefinitions.hpp.
Reviewed-by: dholmes, ysr
author | johnc |
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date | Mon, 19 Dec 2011 10:02:05 -0800 |
parents | f95d63e2154a |
children | 1a2723f7ad8e |
rev | line source |
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0 | 1 /* |
1972 | 2 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved. |
0 | 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 * | |
1552
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
1972 | 25 #include "precompiled.hpp" |
26 #include "memory/gcLocker.inline.hpp" | |
27 #include "memory/resourceArea.hpp" | |
28 #include "memory/sharedHeap.hpp" | |
0 | 29 |
30 volatile jint GC_locker::_jni_lock_count = 0; | |
31 volatile jint GC_locker::_lock_count = 0; | |
32 volatile bool GC_locker::_needs_gc = false; | |
33 volatile bool GC_locker::_doing_gc = false; | |
34 | |
35 void GC_locker::stall_until_clear() { | |
36 assert(!JavaThread::current()->in_critical(), "Would deadlock"); | |
139
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37 if (PrintJNIGCStalls && PrintGCDetails) { |
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38 ResourceMark rm; // JavaThread::name() allocates to convert to UTF8 |
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39 gclog_or_tty->print_cr( |
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40 "Allocation failed. Thread \"%s\" is stalled by JNI critical section.", |
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41 JavaThread::current()->name()); |
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42 } |
0 | 43 MutexLocker ml(JNICritical_lock); |
44 // Wait for _needs_gc to be cleared | |
45 while (GC_locker::needs_gc()) { | |
46 JNICritical_lock->wait(); | |
47 } | |
48 } | |
49 | |
50 void GC_locker::jni_lock_slow() { | |
51 MutexLocker mu(JNICritical_lock); | |
52 // Block entering threads if we know at least one thread is in a | |
53 // JNI critical region and we need a GC. | |
54 // We check that at least one thread is in a critical region before | |
55 // blocking because blocked threads are woken up by a thread exiting | |
56 // a JNI critical region. | |
57 while ((is_jni_active() && needs_gc()) || _doing_gc) { | |
58 JNICritical_lock->wait(); | |
59 } | |
60 jni_lock(); | |
61 } | |
62 | |
63 void GC_locker::jni_unlock_slow() { | |
64 MutexLocker mu(JNICritical_lock); | |
65 jni_unlock(); | |
66 if (needs_gc() && !is_jni_active()) { | |
67 // We're the last thread out. Cause a GC to occur. | |
68 // GC will also check is_active, so this check is not | |
69 // strictly needed. It's added here to make it clear that | |
70 // the GC will NOT be performed if any other caller | |
71 // of GC_locker::lock() still needs GC locked. | |
72 if (!is_active()) { | |
73 _doing_gc = true; | |
74 { | |
75 // Must give up the lock while at a safepoint | |
76 MutexUnlocker munlock(JNICritical_lock); | |
77 Universe::heap()->collect(GCCause::_gc_locker); | |
78 } | |
79 _doing_gc = false; | |
80 } | |
81 clear_needs_gc(); | |
82 JNICritical_lock->notify_all(); | |
83 } | |
84 } | |
85 | |
86 // Implementation of No_GC_Verifier | |
87 | |
88 #ifdef ASSERT | |
89 | |
90 No_GC_Verifier::No_GC_Verifier(bool verifygc) { | |
91 _verifygc = verifygc; | |
92 if (_verifygc) { | |
93 CollectedHeap* h = Universe::heap(); | |
94 assert(!h->is_gc_active(), "GC active during No_GC_Verifier"); | |
95 _old_invocations = h->total_collections(); | |
96 } | |
97 } | |
98 | |
99 | |
100 No_GC_Verifier::~No_GC_Verifier() { | |
101 if (_verifygc) { | |
102 CollectedHeap* h = Universe::heap(); | |
103 assert(!h->is_gc_active(), "GC active during No_GC_Verifier"); | |
104 if (_old_invocations != h->total_collections()) { | |
105 fatal("collection in a No_GC_Verifier secured function"); | |
106 } | |
107 } | |
108 } | |
109 | |
110 Pause_No_GC_Verifier::Pause_No_GC_Verifier(No_GC_Verifier * ngcv) { | |
111 _ngcv = ngcv; | |
112 if (_ngcv->_verifygc) { | |
113 // if we were verifying, then make sure that nothing is | |
114 // wrong before we "pause" verification | |
115 CollectedHeap* h = Universe::heap(); | |
116 assert(!h->is_gc_active(), "GC active during No_GC_Verifier"); | |
117 if (_ngcv->_old_invocations != h->total_collections()) { | |
118 fatal("collection in a No_GC_Verifier secured function"); | |
119 } | |
120 } | |
121 } | |
122 | |
123 | |
124 Pause_No_GC_Verifier::~Pause_No_GC_Verifier() { | |
125 if (_ngcv->_verifygc) { | |
126 // if we were verifying before, then reenable verification | |
127 CollectedHeap* h = Universe::heap(); | |
128 assert(!h->is_gc_active(), "GC active during No_GC_Verifier"); | |
129 _ngcv->_old_invocations = h->total_collections(); | |
130 } | |
131 } | |
132 | |
133 | |
134 // JRT_LEAF rules: | |
135 // A JRT_LEAF method may not interfere with safepointing by | |
136 // 1) acquiring or blocking on a Mutex or JavaLock - checked | |
137 // 2) allocating heap memory - checked | |
138 // 3) executing a VM operation - checked | |
139 // 4) executing a system call (including malloc) that could block or grab a lock | |
140 // 5) invoking GC | |
141 // 6) reaching a safepoint | |
142 // 7) running too long | |
143 // Nor may any method it calls. | |
144 JRT_Leaf_Verifier::JRT_Leaf_Verifier() | |
145 : No_Safepoint_Verifier(true, JRT_Leaf_Verifier::should_verify_GC()) | |
146 { | |
147 } | |
148 | |
149 JRT_Leaf_Verifier::~JRT_Leaf_Verifier() | |
150 { | |
151 } | |
152 | |
153 bool JRT_Leaf_Verifier::should_verify_GC() { | |
154 switch (JavaThread::current()->thread_state()) { | |
155 case _thread_in_Java: | |
156 // is in a leaf routine, there must be no safepoint. | |
157 return true; | |
158 case _thread_in_native: | |
159 // A native thread is not subject to safepoints. | |
160 // Even while it is in a leaf routine, GC is ok | |
161 return false; | |
162 default: | |
163 // Leaf routines cannot be called from other contexts. | |
164 ShouldNotReachHere(); | |
165 return false; | |
166 } | |
167 } | |
168 #endif |