1 /* 2 * Copyright (c) 2018, Red Hat, Inc. and/or its affiliates. 3 * 4 * This code is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License version 2 only, as 6 * published by the Free Software Foundation. 7 * 8 * This code is distributed in the hope that it will be useful, but WITHOUT 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 11 * version 2 for more details (a copy is included in the LICENSE file that 12 * accompanied this code). 13 * 14 * You should have received a copy of the GNU General Public License version 15 * 2 along with this work; if not, write to the Free Software Foundation, 16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 17 * 18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 19 * or visit www.oracle.com if you need additional information or have any 20 * questions. 21 * 22 */ 23 24 #include "precompiled.hpp" 25 #include "gc_implementation/shenandoah/shenandoahCollectionSet.hpp" 26 #include "gc_implementation/shenandoah/heuristics/shenandoahCompactHeuristics.hpp" 27 #include "gc_implementation/shenandoah/shenandoahFreeSet.hpp" 28 #include "gc_implementation/shenandoah/shenandoahHeapRegion.hpp" 29 #include "gc_implementation/shenandoah/shenandoahLogging.hpp" 30 31 ShenandoahCompactHeuristics::ShenandoahCompactHeuristics() : ShenandoahHeuristics() { 32 SHENANDOAH_ERGO_ENABLE_FLAG(ShenandoahUncommit); 33 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahAllocationThreshold, 10); 34 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahImmediateThreshold, 100); 35 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahUncommitDelay, 5000); 36 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahGuaranteedGCInterval, 30000); 37 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahGarbageThreshold, 20); 38 } 39 40 bool ShenandoahCompactHeuristics::should_start_normal_gc() const { 41 ShenandoahHeap* heap = ShenandoahHeap::heap(); 42 43 size_t available = heap->free_set()->available(); 44 double last_time_ms = (os::elapsedTime() - _last_cycle_end) * 1000; 45 bool periodic_gc = (last_time_ms > ShenandoahGuaranteedGCInterval); 46 size_t bytes_allocated = heap->bytes_allocated_since_gc_start(); 47 size_t threshold_bytes_allocated = heap->capacity() * ShenandoahAllocationThreshold / 100; 48 49 if (available < threshold_bytes_allocated || bytes_allocated > threshold_bytes_allocated) { 50 log_info(gc,ergo)("Concurrent marking triggered. Free: " SIZE_FORMAT "M, Allocated: " SIZE_FORMAT "M, Alloc Threshold: " SIZE_FORMAT "M", 51 available / M, bytes_allocated / M, threshold_bytes_allocated / M); 52 return true; 53 } else if (periodic_gc) { 54 log_info(gc,ergo)("Periodic GC triggered. Time since last GC: %.0f ms, Guaranteed Interval: " UINTX_FORMAT " ms", 55 last_time_ms, ShenandoahGuaranteedGCInterval); 56 return true; 57 } 58 59 return false; 60 } 61 62 void ShenandoahCompactHeuristics::choose_collection_set_from_regiondata(ShenandoahCollectionSet* cset, 63 RegionData* data, size_t size, 64 size_t actual_free) { 65 66 // Do not select too large CSet that would overflow the available free space 67 size_t max_cset = actual_free * 3 / 4; 68 69 log_info(gc, ergo)("CSet Selection. Actual Free: " SIZE_FORMAT "M, Max CSet: " SIZE_FORMAT "M", 70 actual_free / M, max_cset / M); 71 72 size_t threshold = ShenandoahHeapRegion::region_size_bytes() * ShenandoahGarbageThreshold / 100; 73 74 size_t live_cset = 0; 75 for (size_t idx = 0; idx < size; idx++) { 76 ShenandoahHeapRegion* r = data[idx]._region; 77 size_t new_cset = live_cset + r->get_live_data_bytes(); 78 if (new_cset < max_cset && r->garbage() > threshold) { 79 live_cset = new_cset; 80 cset->add_region(r); 81 } 82 } 83 } 84 85 const char* ShenandoahCompactHeuristics::name() { 86 return "compact"; 87 } 88 89 bool ShenandoahCompactHeuristics::is_diagnostic() { 90 return false; 91 } 92 93 bool ShenandoahCompactHeuristics::is_experimental() { 94 return false; 95 }