1 /* |
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2 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. |
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8 * |
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9 * This code is distributed in the hope that it will be useful, but WITHOUT |
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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12 * version 2 for more details (a copy is included in the LICENSE file that |
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13 * accompanied this code). |
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14 * |
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15 * You should have received a copy of the GNU General Public License version |
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16 * 2 along with this work; if not, write to the Free Software Foundation, |
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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18 * |
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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. |
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22 * |
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23 */ |
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24 |
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25 #include "precompiled.hpp" |
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26 #include "runtime/orderAccess.inline.hpp" |
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27 #include "trace/tracingExport.hpp" |
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28 |
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29 // Allow lock-free reads of _sampler_thread. |
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30 Thread* volatile TracingExport::_sampler_thread = NULL; |
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31 |
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32 Thread* TracingExport::sampler_thread_acquire() { |
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33 return (Thread*)OrderAccess::load_acquire(&_sampler_thread); |
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34 } |
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35 |
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36 void TracingExport::set_sampler_thread_with_lock(Thread* thread) { |
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37 // Grab Threads_lock to avoid conflicts with Thread-SMR scans. |
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38 MutexLocker ml(Threads_lock); |
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39 assert(thread == NULL || _sampler_thread == NULL, "_sampler_thread should not already be set."); |
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40 // To match with the lock-free load_acquire(): |
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41 OrderAccess::release_store(&_sampler_thread, thread); |
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42 } |
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