1 /* 2 * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 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/parallel/asPSOldGen.hpp" 27 #include "gc/parallel/parallelScavengeHeap.hpp" 28 #include "gc/parallel/psAdaptiveSizePolicy.hpp" 29 #include "gc/shared/cardTableBarrierSet.hpp" 30 #include "gc/shared/genArguments.hpp" 31 #include "oops/oop.inline.hpp" 32 #include "runtime/java.hpp" 33 #include "utilities/align.hpp" 34 35 // Whereas PSOldGen takes the maximum size of the generation 36 // (which doesn't change in the case of PSOldGen) as a parameter, 37 // ASPSOldGen takes the upper limit on the size of 38 // the generation as a parameter. In ASPSOldGen the 39 // maximum size of the generation can change as the boundary 40 // moves. The "maximum size of the generation" is still a valid 41 // concept since the generation can grow and shrink within that 42 // maximum. There are lots of useful checks that use that 43 // maximum. In PSOldGen the method max_gen_size() returns 44 // _max_gen_size (as set by the PSOldGen constructor). This 45 // is how it always worked. In ASPSOldGen max_gen_size() 46 // returned the size of the reserved space for the generation. 47 // That can change as the boundary moves. Below the limit of 48 // the size of the generation is passed to the PSOldGen constructor 49 // for "_max_gen_size" (have to pass something) but it is not used later. 50 // 51 ASPSOldGen::ASPSOldGen(size_t initial_size, 52 size_t min_size, 53 size_t size_limit, 54 const char* gen_name, 55 int level) : 56 PSOldGen(initial_size, min_size, size_limit, gen_name, level), 57 _gen_size_limit(size_limit) 58 {} 59 60 ASPSOldGen::ASPSOldGen(PSVirtualSpace* vs, 61 size_t initial_size, 62 size_t min_size, 63 size_t size_limit, 64 const char* gen_name, 65 int level) : 66 PSOldGen(initial_size, min_size, size_limit, gen_name, level), 67 _gen_size_limit(size_limit) 68 { 69 _virtual_space = vs; 70 } 71 72 void ASPSOldGen::initialize_work(const char* perf_data_name, int level) { 73 PSOldGen::initialize_work(perf_data_name, level); 74 75 // The old gen can grow to gen_size_limit(). _reserve reflects only 76 // the current maximum that can be committed. 77 assert(_reserved.byte_size() <= gen_size_limit(), "Consistency check"); 78 79 initialize_performance_counters(perf_data_name, level); 80 } 81 82 void ASPSOldGen::reset_after_change() { 83 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(), 84 (HeapWord*)virtual_space()->high_boundary()); 85 post_resize(); 86 } 87 88 89 size_t ASPSOldGen::available_for_expansion() { 90 assert(virtual_space()->is_aligned(gen_size_limit()), "not aligned"); 91 assert(gen_size_limit() >= virtual_space()->committed_size(), "bad gen size"); 92 93 size_t result = gen_size_limit() - virtual_space()->committed_size(); 94 size_t result_aligned = align_down(result, GenAlignment); 95 return result_aligned; 96 } 97 98 size_t ASPSOldGen::available_for_contraction() { 99 size_t uncommitted_bytes = virtual_space()->uncommitted_size(); 100 if (uncommitted_bytes != 0) { 101 return uncommitted_bytes; 102 } 103 104 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 105 PSAdaptiveSizePolicy* policy = heap->size_policy(); 106 const size_t working_size = 107 used_in_bytes() + (size_t) policy->avg_promoted()->padded_average(); 108 const size_t working_aligned = align_up(working_size, GenAlignment); 109 const size_t working_or_min = MAX2(working_aligned, min_gen_size()); 110 if (working_or_min > reserved().byte_size()) { 111 // If the used or minimum gen size (aligned up) is greater 112 // than the total reserved size, then the space available 113 // for contraction should (after proper alignment) be 0 114 return 0; 115 } 116 const size_t max_contraction = 117 reserved().byte_size() - working_or_min; 118 119 // Use the "increment" fraction instead of the "decrement" fraction 120 // to allow the other gen to expand more aggressively. The 121 // "decrement" fraction is conservative because its intent is to 122 // only reduce the footprint. 123 124 size_t result = policy->promo_increment_aligned_down(max_contraction); 125 // Also adjust for inter-generational alignment 126 size_t result_aligned = align_down(result, GenAlignment); 127 128 Log(gc, ergo) log; 129 if (log.is_trace()) { 130 size_t working_promoted = (size_t) policy->avg_promoted()->padded_average(); 131 size_t promo_increment = policy->promo_increment(max_contraction); 132 log.trace("ASPSOldGen::available_for_contraction: " SIZE_FORMAT " K / " SIZE_FORMAT_HEX, result_aligned/K, result_aligned); 133 log.trace(" reserved().byte_size() " SIZE_FORMAT " K / " SIZE_FORMAT_HEX, reserved().byte_size()/K, reserved().byte_size()); 134 log.trace(" padded promoted " SIZE_FORMAT " K / " SIZE_FORMAT_HEX, working_promoted/K, working_promoted); 135 log.trace(" used " SIZE_FORMAT " K / " SIZE_FORMAT_HEX, used_in_bytes()/K, used_in_bytes()); 136 log.trace(" min_gen_size() " SIZE_FORMAT " K / " SIZE_FORMAT_HEX, min_gen_size()/K, min_gen_size()); 137 log.trace(" max_contraction " SIZE_FORMAT " K / " SIZE_FORMAT_HEX, max_contraction/K, max_contraction); 138 log.trace(" without alignment " SIZE_FORMAT " K / " SIZE_FORMAT_HEX, promo_increment/K, promo_increment); 139 log.trace(" alignment " SIZE_FORMAT_HEX, GenAlignment); 140 } 141 142 assert(result_aligned <= max_contraction, "arithmetic is wrong"); 143 return result_aligned; 144 }