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
27 #include "gc/shenandoah/heuristics/shenandoahPassiveHeuristics.hpp"
28 #include "gc/shenandoah/shenandoahCollectionSet.hpp"
29 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
30 #include "gc/shenandoah/shenandoahHeapRegion.inline.hpp"
31 #include "logging/log.hpp"
32 #include "logging/logTag.hpp"
33
34 bool ShenandoahPassiveHeuristics::should_start_gc() {
35 // Never do concurrent GCs.
36 return false;
37 }
38
39 bool ShenandoahPassiveHeuristics::should_unload_classes() {
40 // Always unload classes, if we can.
41 return can_unload_classes();
42 }
43
44 bool ShenandoahPassiveHeuristics::should_degenerate_cycle() {
45 // Always fail to Degenerated GC, if enabled
46 return ShenandoahDegeneratedGC;
47 }
48
49 void ShenandoahPassiveHeuristics::choose_collection_set_from_regiondata(ShenandoahCollectionSet* cset,
50 RegionData* data, size_t size,
51 size_t actual_free) {
52 assert(ShenandoahDegeneratedGC, "This path is only taken for Degenerated GC");
53
54 // Do not select too large CSet that would overflow the available free space.
55 // Take at least the entire evacuation reserve, and be free to overflow to free space.
56 size_t max_capacity = ShenandoahHeap::heap()->max_capacity();
57 size_t available = MAX2(max_capacity / 100 * ShenandoahEvacReserve, actual_free);
58 size_t max_cset = (size_t)(available / ShenandoahEvacWaste);
59
60 log_info(gc, ergo)("CSet Selection. Actual Free: " SIZE_FORMAT "%s, Max CSet: " SIZE_FORMAT "%s",
61 byte_size_in_proper_unit(actual_free), proper_unit_for_byte_size(actual_free),
62 byte_size_in_proper_unit(max_cset), proper_unit_for_byte_size(max_cset));
63
64 size_t threshold = ShenandoahHeapRegion::region_size_bytes() * ShenandoahGarbageThreshold / 100;
65
66 size_t live_cset = 0;
67 for (size_t idx = 0; idx < size; idx++) {
68 ShenandoahHeapRegion* r = data[idx]._region;
69 size_t new_cset = live_cset + r->get_live_data_bytes();
70 if (new_cset < max_cset && r->garbage() > threshold) {
71 live_cset = new_cset;
72 cset->add_region(r);
73 }
74 }
75 }
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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
27 #include "gc/shenandoah/heuristics/shenandoahPassiveHeuristics.hpp"
28 #include "gc/shenandoah/shenandoahCollectionSet.hpp"
29 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
30 #include "gc/shenandoah/shenandoahHeapRegion.inline.hpp"
31 #include "logging/log.hpp"
32 #include "logging/logTag.hpp"
33
34 ShenandoahPassiveHeuristics::ShenandoahPassiveHeuristics(ShenandoahSpaceInfo* space_info) :
35 ShenandoahHeuristics(space_info) {}
36
37 bool ShenandoahPassiveHeuristics::should_start_gc() {
38 // Never do concurrent GCs.
39 return false;
40 }
41
42 bool ShenandoahPassiveHeuristics::should_unload_classes() {
43 // Always unload classes, if we can.
44 return can_unload_classes();
45 }
46
47 bool ShenandoahPassiveHeuristics::should_degenerate_cycle() {
48 // Always fail to Degenerated GC, if enabled
49 return ShenandoahDegeneratedGC;
50 }
51
52 void ShenandoahPassiveHeuristics::choose_collection_set_from_regiondata(ShenandoahCollectionSet* cset,
53 RegionData* data, size_t size,
54 size_t actual_free) {
55 assert(ShenandoahDegeneratedGC, "This path is only taken for Degenerated GC");
56
57 // Do not select too large CSet that would overflow the available free space.
58 // Take at least the entire evacuation reserve, and be free to overflow to free space.
59 size_t max_capacity = _space_info->max_capacity();
60 size_t available = MAX2(max_capacity / 100 * ShenandoahEvacReserve, actual_free);
61 size_t max_cset = (size_t)(available / ShenandoahEvacWaste);
62
63 log_info(gc, ergo)("CSet Selection. Actual Free: " SIZE_FORMAT "%s, Max CSet: " SIZE_FORMAT "%s",
64 byte_size_in_proper_unit(actual_free), proper_unit_for_byte_size(actual_free),
65 byte_size_in_proper_unit(max_cset), proper_unit_for_byte_size(max_cset));
66
67 size_t threshold = ShenandoahHeapRegion::region_size_bytes() * ShenandoahGarbageThreshold / 100;
68
69 size_t live_cset = 0;
70 for (size_t idx = 0; idx < size; idx++) {
71 ShenandoahHeapRegion* r = data[idx]._region;
72 size_t new_cset = live_cset + r->get_live_data_bytes();
73 if (new_cset < max_cset && r->garbage() > threshold) {
74 live_cset = new_cset;
75 cset->add_region(r);
76 }
77 }
78 }
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