Mercurial > hg > truffle
annotate src/os/windows/vm/threadCritical_windows.cpp @ 20295:3f2894c5052e
8048112: G1 Full GC needs to support the case when the very first region is not available
Summary: Refactor preparation for compaction during Full GC so that it lazily initializes the first compaction point. This also avoids problems later when the first region may not be committed. Also reviewed by K. Barrett.
Reviewed-by: brutisso
author | tschatzl |
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date | Mon, 21 Jul 2014 10:00:31 +0200 |
parents | f34d701e952e |
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rev | line source |
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0 | 1 /* |
1972 | 2 * Copyright (c) 2001, 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 | |
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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 * | |
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6941466: Oracle rebranding changes for Hotspot repositories
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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" |
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f34d701e952e
8003935: Simplify the needed includes for using Thread::current()
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26 #include "runtime/thread.inline.hpp" |
1972 | 27 #include "runtime/threadCritical.hpp" |
0 | 28 |
29 // OS-includes here | |
30 # include <windows.h> | |
31 # include <winbase.h> | |
32 | |
33 // | |
34 // See threadCritical.hpp for details of this class. | |
35 // | |
36 | |
37 static bool initialized = false; | |
38 static volatile jint lock_count = -1; | |
39 static HANDLE lock_event; | |
40 static DWORD lock_owner = -1; | |
41 | |
42 // | |
43 // Note that Microsoft's critical region code contains a race | |
44 // condition, and is not suitable for use. A thread holding the | |
45 // critical section cannot safely suspend a thread attempting | |
46 // to enter the critical region. The failure mode is that both | |
47 // threads are permanently suspended. | |
48 // | |
49 // I experiemented with the use of ordinary windows mutex objects | |
50 // and found them ~30 times slower than the critical region code. | |
51 // | |
52 | |
53 void ThreadCritical::initialize() { | |
54 } | |
55 | |
56 void ThreadCritical::release() { | |
57 assert(lock_owner == -1, "Mutex being deleted while owned."); | |
58 assert(lock_count == -1, "Mutex being deleted while recursively locked"); | |
59 assert(lock_event != NULL, "Sanity check"); | |
60 CloseHandle(lock_event); | |
61 } | |
62 | |
63 ThreadCritical::ThreadCritical() { | |
64 DWORD current_thread = GetCurrentThreadId(); | |
65 | |
66 if (lock_owner != current_thread) { | |
67 // Grab the lock before doing anything. | |
68 while (Atomic::cmpxchg(0, &lock_count, -1) != -1) { | |
69 if (initialized) { | |
70 DWORD ret = WaitForSingleObject(lock_event, INFINITE); | |
71 assert(ret == WAIT_OBJECT_0, "unexpected return value from WaitForSingleObject"); | |
72 } | |
73 } | |
74 | |
75 // Make sure the event object is allocated. | |
76 if (!initialized) { | |
77 // Locking will not work correctly unless this is autoreset. | |
78 lock_event = CreateEvent(NULL, false, false, NULL); | |
79 initialized = true; | |
80 } | |
81 | |
82 assert(lock_owner == -1, "Lock acquired illegally."); | |
83 lock_owner = current_thread; | |
84 } else { | |
85 // Atomicity isn't required. Bump the recursion count. | |
86 lock_count++; | |
87 } | |
88 | |
89 assert(lock_owner == GetCurrentThreadId(), "Lock acquired illegally."); | |
90 } | |
91 | |
92 ThreadCritical::~ThreadCritical() { | |
93 assert(lock_owner == GetCurrentThreadId(), "unlock attempt by wrong thread"); | |
94 assert(lock_count >= 0, "Attempt to unlock when already unlocked"); | |
95 | |
96 if (lock_count == 0) { | |
97 // We're going to unlock | |
98 lock_owner = -1; | |
99 lock_count = -1; | |
100 // No lost wakeups, lock_event stays signaled until reset. | |
101 DWORD ret = SetEvent(lock_event); | |
102 assert(ret != 0, "unexpected return value from SetEvent"); | |
103 } else { | |
104 // Just unwinding a recursive lock; | |
105 lock_count--; | |
106 } | |
107 } |