1 /* 2 * Copyright (c) 2003, 2010, 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_implementation/parallelScavenge/asPSOldGen.hpp" 27 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp" 28 #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp" 29 #include "gc_implementation/parallelScavenge/psMarkSweepDecorator.hpp" 30 #include "memory/cardTableModRefBS.hpp" 31 #include "oops/oop.inline.hpp" 32 #include "runtime/java.hpp" 33 34 // Whereas PSOldGen takes the maximum size of the generation 35 // (which doesn't change in the case of PSOldGen) as a parameter, 36 // ASPSOldGen takes the upper limit on the size of 37 // the generation as a parameter. In ASPSOldGen the 38 // maximum size of the generation can change as the boundary 39 // moves. The "maximum size of the generation" is still a valid 40 // concept since the generation can grow and shrink within that 41 // maximum. There are lots of useful checks that use that 42 // maximum. In PSOldGen the method max_gen_size() returns 43 // _max_gen_size (as set by the PSOldGen constructor). This 44 // is how it always worked. In ASPSOldGen max_gen_size() 45 // returned the size of the reserved space for the generation. 46 // That can change as the boundary moves. Below the limit of 47 // the size of the generation is passed to the PSOldGen constructor 48 // for "_max_gen_size" (have to pass something) but it is not used later. 49 // 50 ASPSOldGen::ASPSOldGen(size_t initial_size, 51 size_t min_size, 52 size_t size_limit, 53 const char* gen_name, 54 int level) : 55 PSOldGen(initial_size, min_size, size_limit, gen_name, level), 56 _gen_size_limit(size_limit) 57 {} 58 59 ASPSOldGen::ASPSOldGen(PSVirtualSpace* vs, 60 size_t initial_size, 61 size_t min_size, 62 size_t size_limit, 63 const char* gen_name, 64 int level) : 65 PSOldGen(initial_size, min_size, size_limit, gen_name, level), 66 _gen_size_limit(size_limit) 67 { 68 _virtual_space = vs; 69 } 70 71 void ASPSOldGen::initialize_work(const char* perf_data_name, int level) { 72 PSOldGen::initialize_work(perf_data_name, level); 73 74 // The old gen can grow to gen_size_limit(). _reserve reflects only 75 // the current maximum that can be committed. 76 assert(_reserved.byte_size() <= gen_size_limit(), "Consistency check"); 77 78 initialize_performance_counters(perf_data_name, level); 79 } 80 81 void ASPSOldGen::reset_after_change() { 82 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(), 83 (HeapWord*)virtual_space()->high_boundary()); 84 post_resize(); 85 } 86 87 88 size_t ASPSOldGen::available_for_expansion() { 89 assert(virtual_space()->is_aligned(gen_size_limit()), "not aligned"); 90 assert(gen_size_limit() >= virtual_space()->committed_size(), "bad gen size"); 91 92 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); 93 size_t result = gen_size_limit() - virtual_space()->committed_size(); 94 size_t result_aligned = align_size_down(result, heap->generation_alignment()); 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*)Universe::heap(); 105 const size_t gen_alignment = heap->generation_alignment(); 106 PSAdaptiveSizePolicy* policy = heap->size_policy(); 107 const size_t working_size = 108 used_in_bytes() + (size_t) policy->avg_promoted()->padded_average(); 109 const size_t working_aligned = align_size_up(working_size, gen_alignment); 110 const size_t working_or_min = MAX2(working_aligned, min_gen_size()); 111 if (working_or_min > reserved().byte_size()) { 112 // If the used or minimum gen size (aligned up) is greater 113 // than the total reserved size, then the space available 114 // for contraction should (after proper alignment) be 0 115 return 0; 116 } 117 const size_t max_contraction = 118 reserved().byte_size() - working_or_min; 119 120 // Use the "increment" fraction instead of the "decrement" fraction 121 // to allow the other gen to expand more aggressively. The 122 // "decrement" fraction is conservative because its intent is to 123 // only reduce the footprint. 124 125 size_t result = policy->promo_increment_aligned_down(max_contraction); 126 // Also adjust for inter-generational alignment 127 size_t result_aligned = align_size_down(result, gen_alignment); 128 if (PrintAdaptiveSizePolicy && Verbose) { 129 gclog_or_tty->print_cr("\nASPSOldGen::available_for_contraction:" 130 " %d K / 0x%x", result_aligned/K, result_aligned); 131 gclog_or_tty->print_cr(" reserved().byte_size() %d K / 0x%x ", 132 reserved().byte_size()/K, reserved().byte_size()); 133 size_t working_promoted = (size_t) policy->avg_promoted()->padded_average(); 134 gclog_or_tty->print_cr(" padded promoted %d K / 0x%x", 135 working_promoted/K, working_promoted); 136 gclog_or_tty->print_cr(" used %d K / 0x%x", 137 used_in_bytes()/K, used_in_bytes()); 138 gclog_or_tty->print_cr(" min_gen_size() %d K / 0x%x", 139 min_gen_size()/K, min_gen_size()); 140 gclog_or_tty->print_cr(" max_contraction %d K / 0x%x", 141 max_contraction/K, max_contraction); 142 gclog_or_tty->print_cr(" without alignment %d K / 0x%x", 143 policy->promo_increment(max_contraction)/K, 144 policy->promo_increment(max_contraction)); 145 gclog_or_tty->print_cr(" alignment 0x%x", gen_alignment); 146 } 147 assert(result_aligned <= max_contraction, "arithmetic is wrong"); 148 return result_aligned; 149 }