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_RUNTIME_HANDSHAKE_HPP
26 #define SHARE_RUNTIME_HANDSHAKE_HPP
27
28 #include "memory/allocation.hpp"
29 #include "runtime/flags/flagSetting.hpp"
30 #include "runtime/semaphore.hpp"
31
32 class ThreadClosure;
33 class JavaThread;
34
35 // A handshake operation is a callback that is executed for each JavaThread
36 // while that thread is in a safepoint safe state. The callback is executed
37 // either by the thread itself or by the VM thread while keeping the thread
38 // in a blocked state. A handshake can be performed with a single
39 // JavaThread as well.
40 class Handshake : public AllStatic {
41 public:
42 // Execution of handshake operation
43 static void execute(ThreadClosure* thread_cl);
44 static bool execute(ThreadClosure* thread_cl, JavaThread* target);
45 };
46
47 class HandshakeOperation;
48
49 // The HandshakeState keep tracks of an ongoing handshake for one JavaThread.
50 // VM thread and JavaThread are serialized with the semaphore making sure
51 // the operation is only done by either VM thread on behalf of the JavaThread
52 // or the JavaThread itself.
53 class HandshakeState {
54 HandshakeOperation* volatile _operation;
55
56 Semaphore _semaphore;
57 bool _thread_in_process_handshake;
58
59 bool claim_handshake_for_vmthread();
60 bool vmthread_can_process_handshake(JavaThread* target);
61
62 void clear_handshake(JavaThread* thread);
63
64 void process_self_inner(JavaThread* thread);
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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_RUNTIME_HANDSHAKE_HPP
26 #define SHARE_RUNTIME_HANDSHAKE_HPP
27
28 #include "memory/allocation.hpp"
29 #include "memory/iterator.hpp"
30 #include "runtime/flags/flagSetting.hpp"
31 #include "runtime/semaphore.hpp"
32
33 class JavaThread;
34
35 // A handshake closure is a callback that is executed for each JavaThread
36 // while that thread is in a safepoint safe state. The callback is executed
37 // either by the thread itself or by the VM thread while keeping the thread
38 // in a blocked state. A handshake can be performed with a single
39 // JavaThread as well.
40 class HandshakeClosure : public ThreadClosure {
41 const char* const _name;
42 public:
43 HandshakeClosure(const char* name) : _name(name) {}
44 const char* name() const {
45 return _name;
46 }
47 virtual void do_thread(Thread* thread) = 0;
48 };
49
50 class Handshake : public AllStatic {
51 public:
52 // Execution of handshake operation
53 static void execute(HandshakeClosure* hs_cl);
54 static bool execute(HandshakeClosure* hs_cl, JavaThread* target);
55 };
56
57 class HandshakeOperation;
58
59 // The HandshakeState keep tracks of an ongoing handshake for one JavaThread.
60 // VM thread and JavaThread are serialized with the semaphore making sure
61 // the operation is only done by either VM thread on behalf of the JavaThread
62 // or the JavaThread itself.
63 class HandshakeState {
64 HandshakeOperation* volatile _operation;
65
66 Semaphore _semaphore;
67 bool _thread_in_process_handshake;
68
69 bool claim_handshake_for_vmthread();
70 bool vmthread_can_process_handshake(JavaThread* target);
71
72 void clear_handshake(JavaThread* thread);
73
74 void process_self_inner(JavaThread* thread);
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