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 #include "precompiled.hpp"
26 #include "jfr/recorder/checkpoint/types/traceid/jfrTraceIdEpoch.hpp"
27 #include "runtime/safepoint.hpp"
28 #include "runtime/orderAccess.inline.hpp"
29
30 // Alternating epochs on each rotation allow for concurrent tagging.
31 // The regular epoch shift happens only during a safepoint.
32 // The fence is there only for the emergency dump case which happens outside of safepoint.
33 bool JfrTraceIdEpoch::_epoch_state = false;
34 void JfrTraceIdEpoch::shift_epoch() {
35 _epoch_state = !_epoch_state;
36 if (!SafepointSynchronize::is_at_safepoint()) {
37 OrderAccess::fence();
38 }
39 }
|
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 #include "precompiled.hpp"
26 #include "jfr/recorder/checkpoint/types/traceid/jfrTraceIdEpoch.hpp"
27 #include "runtime/safepoint.hpp"
28 #include "runtime/orderAccess.hpp"
29
30 // Alternating epochs on each rotation allow for concurrent tagging.
31 // The regular epoch shift happens only during a safepoint.
32 // The fence is there only for the emergency dump case which happens outside of safepoint.
33 bool JfrTraceIdEpoch::_epoch_state = false;
34 void JfrTraceIdEpoch::shift_epoch() {
35 _epoch_state = !_epoch_state;
36 if (!SafepointSynchronize::is_at_safepoint()) {
37 OrderAccess::fence();
38 }
39 }
|