1 /* 2 * Copyright (c) 2018, Red Hat, Inc. All rights reserved. 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 26 #include "gc/shenandoah/heuristics/shenandoahPassiveHeuristics.hpp" 27 #include "logging/log.hpp" 28 #include "logging/logTag.hpp" 29 30 ShenandoahPassiveHeuristics::ShenandoahPassiveHeuristics() : ShenandoahAdaptiveHeuristics() { 31 // Do not allow concurrent cycles. 32 FLAG_SET_DEFAULT(ExplicitGCInvokesConcurrent, false); 33 FLAG_SET_DEFAULT(ShenandoahImplicitGCInvokesConcurrent, false); 34 35 // Passive runs with max speed, reacts on allocation failure. 36 FLAG_SET_DEFAULT(ShenandoahPacing, false); 37 38 // No need for evacuation reserve with Full GC, only for Degenerated GC. 39 if (!ShenandoahDegeneratedGC) { 40 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahEvacReserve, 0); 41 } 42 43 // Disable known barriers by default. 44 SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahSATBBarrier); 45 SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahKeepAliveBarrier); 46 SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahWriteBarrier); 47 SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahReadBarrier); 48 SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahStoreValEnqueueBarrier); 49 SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahStoreValReadBarrier); 50 SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahCASBarrier); 51 SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahAcmpBarrier); 52 SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahCloneBarrier); 53 } 54 55 bool ShenandoahPassiveHeuristics::should_start_normal_gc() const { 56 // Never do concurrent GCs. 57 return false; 58 } 59 60 bool ShenandoahPassiveHeuristics::should_process_references() { 61 // Always process references, if we can. 62 return can_process_references(); 63 } 64 65 bool ShenandoahPassiveHeuristics::should_unload_classes() { 66 // Always unload classes, if we can. 67 return can_unload_classes(); 68 } 69 70 bool ShenandoahPassiveHeuristics::should_degenerate_cycle() { 71 // Always fail to Degenerated GC, if enabled 72 return ShenandoahDegeneratedGC; 73 } 74 75 const char* ShenandoahPassiveHeuristics::name() { 76 return "passive"; 77 } 78 79 bool ShenandoahPassiveHeuristics::is_diagnostic() { 80 return true; 81 } 82 83 bool ShenandoahPassiveHeuristics::is_experimental() { 84 return false; 85 }