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 "gc/g1/g1CollectedHeap.inline.hpp"
27 #include "gc/g1/g1CollectorPolicy.hpp"
28 #include "gc/g1/g1YoungRemSetSamplingThread.hpp"
29 #include "gc/g1/heapRegion.inline.hpp"
30 #include "gc/g1/heapRegionRemSet.hpp"
31 #include "gc/g1/suspendibleThreadSet.hpp"
32 #include "runtime/mutexLocker.hpp"
33
34 void G1YoungRemSetSamplingThread::run() {
35 initialize_in_thread();
36 wait_for_universe_init();
37
38 run_service();
39
40 terminate();
41 }
42
43 void G1YoungRemSetSamplingThread::stop() {
44 // it is ok to take late safepoints here, if needed
45 {
46 MutexLockerEx mu(Terminator_lock);
47 _should_terminate = true;
97 }
98
99 void G1YoungRemSetSamplingThread::sample_young_list_rs_lengths() {
100 SuspendibleThreadSetJoiner sts;
101 G1CollectedHeap* g1h = G1CollectedHeap::heap();
102 G1CollectorPolicy* g1p = g1h->g1_policy();
103 if (g1p->adaptive_young_list_length()) {
104 int regions_visited = 0;
105 HeapRegion* hr = g1h->young_list()->first_region();
106 size_t sampled_rs_lengths = 0;
107
108 while (hr != NULL) {
109 size_t rs_length = hr->rem_set()->occupied();
110 sampled_rs_lengths += rs_length;
111
112 // The current region may not yet have been added to the
113 // incremental collection set (it gets added when it is
114 // retired as the current allocation region).
115 if (hr->in_collection_set()) {
116 // Update the collection set policy information for this region
117 g1p->update_incremental_cset_info(hr, rs_length);
118 }
119
120 ++regions_visited;
121
122 // we try to yield every time we visit 10 regions
123 if (regions_visited == 10) {
124 if (sts.should_yield()) {
125 sts.yield();
126 // A gc may have occurred and our sampling data is stale and further
127 // traversal of the young list is unsafe
128 return;
129 }
130 regions_visited = 0;
131 }
132 hr = hr->get_next_young_region();
133 }
134 g1p->revise_young_list_target_length_if_necessary(sampled_rs_lengths);
135 }
136 }
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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 "gc/g1/g1CollectedHeap.inline.hpp"
27 #include "gc/g1/g1CollectorPolicy.hpp"
28 #include "gc/g1/g1CollectionSet.hpp"
29 #include "gc/g1/g1YoungRemSetSamplingThread.hpp"
30 #include "gc/g1/heapRegion.inline.hpp"
31 #include "gc/g1/heapRegionRemSet.hpp"
32 #include "gc/g1/suspendibleThreadSet.hpp"
33 #include "runtime/mutexLocker.hpp"
34
35 void G1YoungRemSetSamplingThread::run() {
36 initialize_in_thread();
37 wait_for_universe_init();
38
39 run_service();
40
41 terminate();
42 }
43
44 void G1YoungRemSetSamplingThread::stop() {
45 // it is ok to take late safepoints here, if needed
46 {
47 MutexLockerEx mu(Terminator_lock);
48 _should_terminate = true;
98 }
99
100 void G1YoungRemSetSamplingThread::sample_young_list_rs_lengths() {
101 SuspendibleThreadSetJoiner sts;
102 G1CollectedHeap* g1h = G1CollectedHeap::heap();
103 G1CollectorPolicy* g1p = g1h->g1_policy();
104 if (g1p->adaptive_young_list_length()) {
105 int regions_visited = 0;
106 HeapRegion* hr = g1h->young_list()->first_region();
107 size_t sampled_rs_lengths = 0;
108
109 while (hr != NULL) {
110 size_t rs_length = hr->rem_set()->occupied();
111 sampled_rs_lengths += rs_length;
112
113 // The current region may not yet have been added to the
114 // incremental collection set (it gets added when it is
115 // retired as the current allocation region).
116 if (hr->in_collection_set()) {
117 // Update the collection set policy information for this region
118 g1h->collection_set()->update_young_region_prediction(hr, rs_length);
119 }
120
121 ++regions_visited;
122
123 // we try to yield every time we visit 10 regions
124 if (regions_visited == 10) {
125 if (sts.should_yield()) {
126 sts.yield();
127 // A gc may have occurred and our sampling data is stale and further
128 // traversal of the young list is unsafe
129 return;
130 }
131 regions_visited = 0;
132 }
133 hr = hr->get_next_young_region();
134 }
135 g1p->revise_young_list_target_length_if_necessary(sampled_rs_lengths);
136 }
137 }
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