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
68 void set_operation(JavaThread* thread, HandshakeOperation* op);
69
70 bool has_operation() const {
71 return _operation != NULL;
72 }
73
74 void process_by_self(JavaThread* thread) {
75 if (!_thread_in_process_handshake) {
76 FlagSetting fs(_thread_in_process_handshake, true);
77 process_self_inner(thread);
78 }
79 }
80
81 void process_by_vmthread(JavaThread* target);
82 };
83
84 #endif // SHARE_RUNTIME_HANDSHAKE_HPP
|
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 bool _executed;
42 public:
43 HandshakeOperation() : _executed(false) {}
44
45 void do_handshake(JavaThread* thread);
46 bool thread_has_completed() { return _done.trywait(); }
47 bool executed() const { return _executed; }
48
49 #ifdef ASSERT
50 void check_state() {
51 assert(!_done.trywait(), "Must be zero");
52 }
53 #endif
54
55 // Impl
56 virtual void do_thread(JavaThread* thread) = 0;
57 virtual const char* name() = 0;
58 };
59
60 class Handshake : public AllStatic {
61 public:
62 // Execution of handshake operation
63 static void execute(HandshakeOperation* hs_op);
64 static bool execute(HandshakeOperation* hs_op, JavaThread* target);
65 };
66
67 // The HandshakeState keep tracks of an ongoing handshake for one JavaThread.
68 // VM thread and JavaThread are serialized with the semaphore making sure
69 // the operation is only done by either VM thread on behalf of the JavaThread
70 // or the JavaThread itself.
71 class HandshakeState {
72 HandshakeOperation* volatile _operation;
73
74 Semaphore _semaphore;
75 bool _thread_in_process_handshake;
76
77 bool claim_handshake_for_vmthread();
78 bool vmthread_can_process_handshake(JavaThread* target);
79
80 void clear_handshake(JavaThread* thread);
81
82 void process_self_inner(JavaThread* thread);
83 public:
84 HandshakeState();
85
86 void set_operation(JavaThread* thread, HandshakeOperation* op);
87
88 bool has_operation() const {
89 return _operation != NULL;
90 }
91
92 void process_by_self(JavaThread* thread) {
93 if (!_thread_in_process_handshake) {
94 FlagSetting fs(_thread_in_process_handshake, true);
95 process_self_inner(thread);
96 }
97 }
98
99 bool process_by_vmthread(JavaThread* target);
100 };
101
102 #endif // SHARE_RUNTIME_HANDSHAKE_HPP
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