| /* |
| * Copyright (c) 2018, Red Hat, Inc. All rights reserved. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| |
| #include "gc/shenandoah/heuristics/shenandoahPassiveHeuristics.hpp" |
| #include "gc/shenandoah/shenandoahCollectionSet.hpp" |
| #include "gc/shenandoah/shenandoahHeap.inline.hpp" |
| #include "gc/shenandoah/shenandoahHeapRegion.inline.hpp" |
| #include "logging/log.hpp" |
| #include "logging/logTag.hpp" |
| |
| bool ShenandoahPassiveHeuristics::should_start_gc() const { |
| // Never do concurrent GCs. |
| return false; |
| } |
| |
| bool ShenandoahPassiveHeuristics::should_process_references() { |
| // Always process references, if we can. |
| return can_process_references(); |
| } |
| |
| bool ShenandoahPassiveHeuristics::should_unload_classes() { |
| // Always unload classes, if we can. |
| return can_unload_classes(); |
| } |
| |
| bool ShenandoahPassiveHeuristics::should_degenerate_cycle() { |
| // Always fail to Degenerated GC, if enabled |
| return ShenandoahDegeneratedGC; |
| } |
| |
| void ShenandoahPassiveHeuristics::choose_collection_set_from_regiondata(ShenandoahCollectionSet* cset, |
| RegionData* data, size_t size, |
| size_t actual_free) { |
| assert(ShenandoahDegeneratedGC, "This path is only taken for Degenerated GC"); |
| |
| // Do not select too large CSet that would overflow the available free space. |
| // Take at least the entire evacuation reserve, and be free to overflow to free space. |
| size_t max_capacity = ShenandoahHeap::heap()->max_capacity(); |
| size_t available = MAX2(max_capacity / 100 * ShenandoahEvacReserve, actual_free); |
| size_t max_cset = (size_t)(available / ShenandoahEvacWaste); |
| |
| log_info(gc, ergo)("CSet Selection. Actual Free: " SIZE_FORMAT "%s, Max CSet: " SIZE_FORMAT "%s", |
| byte_size_in_proper_unit(actual_free), proper_unit_for_byte_size(actual_free), |
| byte_size_in_proper_unit(max_cset), proper_unit_for_byte_size(max_cset)); |
| |
| size_t threshold = ShenandoahHeapRegion::region_size_bytes() * ShenandoahGarbageThreshold / 100; |
| |
| size_t live_cset = 0; |
| for (size_t idx = 0; idx < size; idx++) { |
| ShenandoahHeapRegion* r = data[idx]._region; |
| size_t new_cset = live_cset + r->get_live_data_bytes(); |
| if (new_cset < max_cset && r->garbage() > threshold) { |
| live_cset = new_cset; |
| cset->add_region(r); |
| } |
| } |
| } |