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.
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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
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 {
70 _virtual_space = vs;
71 }
72
73 void ASPSOldGen::initialize_work(const char* perf_data_name, int level) {
74
75 PSOldGen::initialize_work(perf_data_name, level);
76
77 // The old gen can grow to gen_size_limit(). _reserve reflects only
78 // the current maximum that can be committed.
79 assert(_reserved.byte_size() <= gen_size_limit(), "Consistency check");
80
81 initialize_performance_counters(perf_data_name, level);
82 }
83
84 void ASPSOldGen::reset_after_change() {
85 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
86 (HeapWord*)virtual_space()->high_boundary());
87 post_resize();
88 }
89
90
91 size_t ASPSOldGen::available_for_expansion() {
92 assert(virtual_space()->is_aligned(gen_size_limit()), "not aligned");
93 assert(gen_size_limit() >= virtual_space()->committed_size(), "bad gen size");
94
95 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
96 size_t result = gen_size_limit() - virtual_space()->committed_size();
97 size_t result_aligned = align_size_down(result, heap->old_gen_alignment());
98 return result_aligned;
99 }
100
101 size_t ASPSOldGen::available_for_contraction() {
102 size_t uncommitted_bytes = virtual_space()->uncommitted_size();
103 if (uncommitted_bytes != 0) {
104 return uncommitted_bytes;
105 }
106
107 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
108 const size_t gen_alignment = heap->old_gen_alignment();
109 PSAdaptiveSizePolicy* policy = heap->size_policy();
110 const size_t working_size =
111 used_in_bytes() + (size_t) policy->avg_promoted()->padded_average();
112 const size_t working_aligned = align_size_up(working_size, gen_alignment);
113 const size_t working_or_min = MAX2(working_aligned, min_gen_size());
114 if (working_or_min > reserved().byte_size()) {
115 // If the used or minimum gen size (aligned up) is greater
116 // than the total reserved size, then the space available
117 // for contraction should (after proper alignment) be 0
118 return 0;
119 }
120 const size_t max_contraction =
121 reserved().byte_size() - working_or_min;
122
123 // Use the "increment" fraction instead of the "decrement" fraction
124 // to allow the other gen to expand more aggressively. The
125 // "decrement" fraction is conservative because its intent is to
126 // only reduce the footprint.
127
128 size_t result = policy->promo_increment_aligned_down(max_contraction);
129 // Also adjust for inter-generational alignment
130 size_t result_aligned = align_size_down(result, gen_alignment);
131 if (PrintAdaptiveSizePolicy && Verbose) {
132 gclog_or_tty->print_cr("\nASPSOldGen::available_for_contraction:"
133 " %d K / 0x%x", result_aligned/K, result_aligned);
134 gclog_or_tty->print_cr(" reserved().byte_size() %d K / 0x%x ",
135 reserved().byte_size()/K, reserved().byte_size());
136 size_t working_promoted = (size_t) policy->avg_promoted()->padded_average();
137 gclog_or_tty->print_cr(" padded promoted %d K / 0x%x",
138 working_promoted/K, working_promoted);
139 gclog_or_tty->print_cr(" used %d K / 0x%x",
140 used_in_bytes()/K, used_in_bytes());
141 gclog_or_tty->print_cr(" min_gen_size() %d K / 0x%x",
142 min_gen_size()/K, min_gen_size());
143 gclog_or_tty->print_cr(" max_contraction %d K / 0x%x",
144 max_contraction/K, max_contraction);
145 gclog_or_tty->print_cr(" without alignment %d K / 0x%x",
146 policy->promo_increment(max_contraction)/K,
147 policy->promo_increment(max_contraction));
148 gclog_or_tty->print_cr(" alignment 0x%x", gen_alignment);
149 }
150 assert(result_aligned <= max_contraction, "arithmetic is wrong");
151 return result_aligned;
152 }