Mercurial > hg > graal-compiler
comparison src/os/windows/vm/threadCritical_windows.cpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
parents | |
children | c18cbe5936b8 |
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1 /* | |
2 * Copyright 2001-2003 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/_threadCritical_windows.cpp.incl" | |
27 | |
28 // OS-includes here | |
29 # include <windows.h> | |
30 # include <winbase.h> | |
31 | |
32 // | |
33 // See threadCritical.hpp for details of this class. | |
34 // | |
35 | |
36 static bool initialized = false; | |
37 static volatile jint lock_count = -1; | |
38 static HANDLE lock_event; | |
39 static DWORD lock_owner = -1; | |
40 | |
41 // | |
42 // Note that Microsoft's critical region code contains a race | |
43 // condition, and is not suitable for use. A thread holding the | |
44 // critical section cannot safely suspend a thread attempting | |
45 // to enter the critical region. The failure mode is that both | |
46 // threads are permanently suspended. | |
47 // | |
48 // I experiemented with the use of ordinary windows mutex objects | |
49 // and found them ~30 times slower than the critical region code. | |
50 // | |
51 | |
52 void ThreadCritical::initialize() { | |
53 } | |
54 | |
55 void ThreadCritical::release() { | |
56 assert(lock_owner == -1, "Mutex being deleted while owned."); | |
57 assert(lock_count == -1, "Mutex being deleted while recursively locked"); | |
58 assert(lock_event != NULL, "Sanity check"); | |
59 CloseHandle(lock_event); | |
60 } | |
61 | |
62 ThreadCritical::ThreadCritical() { | |
63 DWORD current_thread = GetCurrentThreadId(); | |
64 | |
65 if (lock_owner != current_thread) { | |
66 // Grab the lock before doing anything. | |
67 while (Atomic::cmpxchg(0, &lock_count, -1) != -1) { | |
68 if (initialized) { | |
69 DWORD ret = WaitForSingleObject(lock_event, INFINITE); | |
70 assert(ret == WAIT_OBJECT_0, "unexpected return value from WaitForSingleObject"); | |
71 } | |
72 } | |
73 | |
74 // Make sure the event object is allocated. | |
75 if (!initialized) { | |
76 // Locking will not work correctly unless this is autoreset. | |
77 lock_event = CreateEvent(NULL, false, false, NULL); | |
78 initialized = true; | |
79 } | |
80 | |
81 assert(lock_owner == -1, "Lock acquired illegally."); | |
82 lock_owner = current_thread; | |
83 } else { | |
84 // Atomicity isn't required. Bump the recursion count. | |
85 lock_count++; | |
86 } | |
87 | |
88 assert(lock_owner == GetCurrentThreadId(), "Lock acquired illegally."); | |
89 } | |
90 | |
91 ThreadCritical::~ThreadCritical() { | |
92 assert(lock_owner == GetCurrentThreadId(), "unlock attempt by wrong thread"); | |
93 assert(lock_count >= 0, "Attempt to unlock when already unlocked"); | |
94 | |
95 if (lock_count == 0) { | |
96 // We're going to unlock | |
97 lock_owner = -1; | |
98 lock_count = -1; | |
99 // No lost wakeups, lock_event stays signaled until reset. | |
100 DWORD ret = SetEvent(lock_event); | |
101 assert(ret != 0, "unexpected return value from SetEvent"); | |
102 } else { | |
103 // Just unwinding a recursive lock; | |
104 lock_count--; | |
105 } | |
106 } |