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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24 /*
25 * Per-thread blocking support for JSR166. See the Java-level
26 * Documentation for rationale. Basically, park acts like wait, unpark
27 * like notify.
28 *
29 * 6271289 --
30 * To avoid errors where an os thread expires but the JavaThread still
31 * exists, Parkers are immortal (type-stable) and are recycled across
32 * new threads. This parallels the ParkEvent implementation.
33 * Because park-unpark allow spurious wakeups it is harmless if an
34 * unpark call unparks a new thread using the old Parker reference.
35 *
36 * In the future we'll want to think about eliminating Parker and using
37 * ParkEvent instead. There's considerable duplication between the two
38 * services.
39 *
40 */
41
42 class Parker : public os::PlatformParker {
43 private:
150 FreeNext = NULL ;
151 ListNext = NULL ;
152 ListPrev = NULL ;
153 OnList = 0 ;
154 TState = 0 ;
155 Notified = 0 ;
156 IsWaiting = 0 ;
157 }
158
159 // We use placement-new to force ParkEvent instances to be
160 // aligned on 256-byte address boundaries. This ensures that the least
161 // significant byte of a ParkEvent address is always 0.
162
163 void * operator new (size_t sz) ;
164 void operator delete (void * a) ;
165
166 public:
167 static ParkEvent * Allocate (Thread * t) ;
168 static void Release (ParkEvent * e) ;
169 } ;
|
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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_VM_RUNTIME_PARK_HPP
26 #define SHARE_VM_RUNTIME_PARK_HPP
27
28 #include "utilities/debug.hpp"
29 #include "utilities/globalDefinitions.hpp"
30 /*
31 * Per-thread blocking support for JSR166. See the Java-level
32 * Documentation for rationale. Basically, park acts like wait, unpark
33 * like notify.
34 *
35 * 6271289 --
36 * To avoid errors where an os thread expires but the JavaThread still
37 * exists, Parkers are immortal (type-stable) and are recycled across
38 * new threads. This parallels the ParkEvent implementation.
39 * Because park-unpark allow spurious wakeups it is harmless if an
40 * unpark call unparks a new thread using the old Parker reference.
41 *
42 * In the future we'll want to think about eliminating Parker and using
43 * ParkEvent instead. There's considerable duplication between the two
44 * services.
45 *
46 */
47
48 class Parker : public os::PlatformParker {
49 private:
156 FreeNext = NULL ;
157 ListNext = NULL ;
158 ListPrev = NULL ;
159 OnList = 0 ;
160 TState = 0 ;
161 Notified = 0 ;
162 IsWaiting = 0 ;
163 }
164
165 // We use placement-new to force ParkEvent instances to be
166 // aligned on 256-byte address boundaries. This ensures that the least
167 // significant byte of a ParkEvent address is always 0.
168
169 void * operator new (size_t sz) ;
170 void operator delete (void * a) ;
171
172 public:
173 static ParkEvent * Allocate (Thread * t) ;
174 static void Release (ParkEvent * e) ;
175 } ;
176
177 #endif // SHARE_VM_RUNTIME_PARK_HPP
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