0
|
1 /*
|
|
2 * Copyright 2001-2002 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 // ThreadCritical is used to protect short non-blocking critical sections.
|
|
26 // This class must use no vm facilities that require initialization.
|
|
27 // It is used very early in the vm's initialization, in allocation
|
|
28 // code and other areas. ThreadCritical regions are reentrant.
|
|
29 //
|
|
30 // Due to race conditions during vm exit, some of the os level
|
|
31 // synchronization primitives may not be deallocated at exit. It
|
605
|
32 // is a good plan to implement the platform dependent sections of
|
0
|
33 // code with resources that are recoverable during process
|
|
34 // cleanup by the os. Calling the initialize method before use
|
|
35 // is also problematic, it is best to use preinitialized primitives
|
|
36 // if possible. As an example:
|
|
37 //
|
|
38 // mutex_t mp = DEFAULTMUTEX;
|
|
39 //
|
|
40 // Also note that this class is declared as a StackObj to enforce
|
|
41 // block structured short locks. It cannot be declared a ResourceObj
|
|
42 // or CHeapObj, due to initialization issues.
|
|
43
|
|
44 class ThreadCritical : public StackObj {
|
|
45 friend class os;
|
|
46 private:
|
|
47 static void initialize();
|
|
48 static void release();
|
|
49
|
|
50 public:
|
|
51 ThreadCritical();
|
|
52 ~ThreadCritical();
|
|
53 };
|