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);
65 public:
66 HandshakeState();
67
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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 JavaThread;
33
34 // A handshake operation is a callback that is executed for each JavaThread
35 // while that thread is in a safepoint safe state. The callback is executed
36 // either by the thread itself or by the VM thread while keeping the thread
37 // in a blocked state. A handshake can be performed with a single
38 // JavaThread as well.
39 class HandshakeOperation: public StackObj {
40 static Semaphore _done;
41 const char* _name;
42 bool _executed;
43 public:
44 HandshakeOperation(const char* name) : _name(name), _executed(false) {}
45
46 void do_handshake(JavaThread* thread);
47 bool thread_has_completed() { return _done.trywait(); }
48 bool executed() const { return _executed; }
49 const char* name() { return _name; };
50
51 #ifdef ASSERT
52 void check_state() {
53 assert(!_done.trywait(), "Must be zero");
54 }
55 #endif
56
57 // Impl
58 virtual void do_thread(JavaThread* thread) = 0;
59 };
60
61 class Handshake : public AllStatic {
62 public:
63 // Execution of handshake operation
64 static void execute(HandshakeOperation* hs_op);
65 static bool execute(HandshakeOperation* hs_op, JavaThread* target);
66 };
67
68 // The HandshakeState keep tracks of an ongoing handshake for one JavaThread.
69 // VM thread and JavaThread are serialized with the semaphore making sure
70 // the operation is only done by either VM thread on behalf of the JavaThread
71 // or the JavaThread itself.
72 class HandshakeState {
73 HandshakeOperation* volatile _operation;
74
75 Semaphore _semaphore;
76 bool _thread_in_process_handshake;
77
78 bool claim_handshake_for_vmthread();
79 bool vmthread_can_process_handshake(JavaThread* target);
80
81 void clear_handshake(JavaThread* thread);
82
83 void process_self_inner(JavaThread* thread);
84 public:
85 HandshakeState();
86
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