Mercurial > hg > truffle
annotate agent/src/os/win32/Monitor.cpp @ 1994:6cd6d394f280
7001033: assert(gch->gc_cause() == GCCause::_scavenge_alot || !gch->incremental_collection_failed())
7002546: regression on SpecJbb2005 on 7b118 comparing to 7b117 on small heaps
Summary: Relaxed assertion checking related to incremental_collection_failed flag to allow for ExplicitGCInvokesConcurrent behaviour where we do not want a failing scavenge to bail to a stop-world collection. Parameterized incremental_collection_will_fail() so we can selectively use, or not use, as appropriate, the statistical prediction at specific use sites. This essentially reverts the scavenge bail-out logic to what it was prior to some recent changes that had inadvertently started using the statistical prediction which can be noisy in the presence of bursty loads. Added some associated verbose non-product debugging messages.
Reviewed-by: johnc, tonyp
| author | ysr |
|---|---|
| date | Tue, 07 Dec 2010 21:55:53 -0800 |
| parents | c18cbe5936b8 |
| children |
| rev | line source |
|---|---|
| 0 | 1 /* |
|
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2 * Copyright (c) 2001, Oracle and/or its affiliates. All rights reserved. |
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| 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. | |
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| 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. | |
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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 | |
| 25 #include <stdio.h> | |
| 26 #include <assert.h> | |
| 27 #include "Monitor.hpp" | |
| 28 | |
| 29 Monitor::Monitor() { | |
| 30 _lock_count = -1; // No threads have entered the critical section | |
| 31 _owner = NULL; | |
| 32 _lock_event = CreateEvent(NULL, false, false, NULL); | |
| 33 _wait_event = CreateEvent(NULL, true, false, NULL); | |
| 34 _counter = 0; | |
| 35 _tickets = 0; | |
| 36 _waiters = 0; | |
| 37 } | |
| 38 | |
| 39 Monitor::~Monitor() { | |
| 40 assert(_owner == NULL); // Otherwise, owned monitor being deleted | |
| 41 assert(_lock_count == -1); // Otherwise, monitor being deleted with non -1 lock count | |
| 42 CloseHandle(_lock_event); | |
| 43 CloseHandle(_wait_event); | |
| 44 } | |
| 45 | |
| 46 void | |
| 47 Monitor::lock() { | |
| 48 if (InterlockedIncrement(&_lock_count) == 0) { | |
| 49 // Success, we now own the lock | |
| 50 } else { | |
| 51 DWORD dwRet = WaitForSingleObject((HANDLE)_lock_event, INFINITE); | |
| 52 assert(dwRet == WAIT_OBJECT_0); // Unexpected return value from WaitForSingleObject | |
| 53 } | |
| 54 assert(owner() == NULL); // Otherwise, lock count and owner are inconsistent | |
| 55 setOwner(GetCurrentThread()); | |
| 56 } | |
| 57 | |
| 58 void | |
| 59 Monitor::unlock() { | |
| 60 setOwner(NULL); | |
| 61 if (InterlockedDecrement(&_lock_count) >= 0) { | |
| 62 // Wake a waiting thread up | |
| 63 DWORD dwRet = SetEvent(_lock_event); | |
| 64 assert(dwRet != 0); // Unexpected return value from SetEvent | |
| 65 } | |
| 66 } | |
| 67 | |
| 68 bool | |
| 69 Monitor::wait(long timeout) { | |
| 70 assert(owner() != NULL); | |
| 71 assert(owner() == GetCurrentThread()); | |
| 72 | |
| 73 // 0 means forever. Convert to Windows specific code. | |
| 74 DWORD timeout_value = (timeout == 0) ? INFINITE : timeout; | |
| 75 DWORD which; | |
| 76 | |
| 77 long c = _counter; | |
| 78 bool retry = false; | |
| 79 | |
| 80 _waiters++; | |
| 81 // Loop until condition variable is signaled. The event object is | |
| 82 // set whenever the condition variable is signaled, and tickets will | |
| 83 // reflect the number of threads which have been notified. The counter | |
| 84 // field is used to make sure we don't respond to notifications that | |
| 85 // have occurred *before* we started waiting, and is incremented each | |
| 86 // time the condition variable is signaled. | |
| 87 | |
| 88 while (true) { | |
| 89 | |
| 90 // Leave critical region | |
| 91 unlock(); | |
| 92 | |
| 93 // If this is a retry, let other low-priority threads have a chance | |
| 94 // to run. Make sure that we sleep outside of the critical section. | |
| 95 if (retry) { | |
| 96 Sleep(1); | |
| 97 } else { | |
| 98 retry = true; | |
| 99 } | |
| 100 | |
| 101 which = WaitForSingleObject(_wait_event, timeout_value); | |
| 102 // Enter critical section | |
| 103 lock(); | |
| 104 | |
| 105 if (_tickets != 0 && _counter != c) break; | |
| 106 | |
| 107 if (which == WAIT_TIMEOUT) { | |
| 108 --_waiters; | |
| 109 return true; | |
| 110 } | |
| 111 } | |
| 112 _waiters--; | |
| 113 | |
| 114 // If this was the last thread to be notified, then we need to reset | |
| 115 // the event object. | |
| 116 if (--_tickets == 0) { | |
| 117 ResetEvent(_wait_event); | |
| 118 } | |
| 119 | |
| 120 return false; | |
| 121 } | |
| 122 | |
| 123 // Notify a single thread waiting on this monitor | |
| 124 bool | |
| 125 Monitor::notify() { | |
| 126 assert(ownedBySelf()); // Otherwise, notify on unknown thread | |
| 127 | |
| 128 if (_waiters > _tickets) { | |
| 129 if (!SetEvent(_wait_event)) { | |
| 130 return false; | |
| 131 } | |
| 132 _tickets++; | |
| 133 _counter++; | |
| 134 } | |
| 135 | |
| 136 return true; | |
| 137 } | |
| 138 | |
| 139 // Notify all threads waiting on this monitor | |
| 140 bool | |
| 141 Monitor::notifyAll() { | |
| 142 assert(ownedBySelf()); // Otherwise, notifyAll on unknown thread | |
| 143 | |
| 144 if (_waiters > 0) { | |
| 145 if (!SetEvent(_wait_event)) { | |
| 146 return false; | |
| 147 } | |
| 148 _tickets = _waiters; | |
| 149 _counter++; | |
| 150 } | |
| 151 | |
| 152 return true; | |
| 153 } | |
| 154 | |
| 155 HANDLE | |
| 156 Monitor::owner() { | |
| 157 return _owner; | |
| 158 } | |
| 159 | |
| 160 void | |
| 161 Monitor::setOwner(HANDLE owner) { | |
| 162 if (owner != NULL) { | |
| 163 assert(_owner == NULL); // Setting owner thread of already owned monitor | |
| 164 assert(owner == GetCurrentThread()); // Else should not be doing this | |
| 165 } else { | |
| 166 HANDLE oldOwner = _owner; | |
| 167 assert(oldOwner != NULL); // Removing the owner thread of an unowned mutex | |
| 168 assert(oldOwner == GetCurrentThread()); | |
| 169 } | |
| 170 _owner = owner; | |
| 171 } | |
| 172 | |
| 173 bool | |
| 174 Monitor::ownedBySelf() { | |
| 175 return (_owner == GetCurrentThread()); | |
| 176 } |