1 /*
2 * Copyright (c) 2003, 2015, 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/parallel/psMarkSweepDecorator.hpp"
30 #include "gc/shared/cardTableModRefBS.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 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
94 size_t result = gen_size_limit() - virtual_space()->committed_size();
95 size_t result_aligned = align_down(result, heap->generation_alignment());
96 return result_aligned;
97 }
98
99 size_t ASPSOldGen::available_for_contraction() {
100 size_t uncommitted_bytes = virtual_space()->uncommitted_size();
101 if (uncommitted_bytes != 0) {
102 return uncommitted_bytes;
103 }
104
105 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
106 const size_t gen_alignment = heap->generation_alignment();
107 PSAdaptiveSizePolicy* policy = heap->size_policy();
108 const size_t working_size =
109 used_in_bytes() + (size_t) policy->avg_promoted()->padded_average();
110 const size_t working_aligned = align_up(working_size, gen_alignment);
111 const size_t working_or_min = MAX2(working_aligned, min_gen_size());
112 if (working_or_min > reserved().byte_size()) {
113 // If the used or minimum gen size (aligned up) is greater
114 // than the total reserved size, then the space available
115 // for contraction should (after proper alignment) be 0
116 return 0;
117 }
118 const size_t max_contraction =
119 reserved().byte_size() - working_or_min;
120
121 // Use the "increment" fraction instead of the "decrement" fraction
122 // to allow the other gen to expand more aggressively. The
123 // "decrement" fraction is conservative because its intent is to
124 // only reduce the footprint.
125
126 size_t result = policy->promo_increment_aligned_down(max_contraction);
127 // Also adjust for inter-generational alignment
128 size_t result_aligned = align_down(result, gen_alignment);
129
130 Log(gc, ergo) log;
131 if (log.is_trace()) {
132 size_t working_promoted = (size_t) policy->avg_promoted()->padded_average();
133 size_t promo_increment = policy->promo_increment(max_contraction);
134 log.trace("ASPSOldGen::available_for_contraction: " SIZE_FORMAT " K / " SIZE_FORMAT_HEX, result_aligned/K, result_aligned);
135 log.trace(" reserved().byte_size() " SIZE_FORMAT " K / " SIZE_FORMAT_HEX, reserved().byte_size()/K, reserved().byte_size());
136 log.trace(" padded promoted " SIZE_FORMAT " K / " SIZE_FORMAT_HEX, working_promoted/K, working_promoted);
137 log.trace(" used " SIZE_FORMAT " K / " SIZE_FORMAT_HEX, used_in_bytes()/K, used_in_bytes());
138 log.trace(" min_gen_size() " SIZE_FORMAT " K / " SIZE_FORMAT_HEX, min_gen_size()/K, min_gen_size());
139 log.trace(" max_contraction " SIZE_FORMAT " K / " SIZE_FORMAT_HEX, max_contraction/K, max_contraction);
140 log.trace(" without alignment " SIZE_FORMAT " K / " SIZE_FORMAT_HEX, promo_increment/K, promo_increment);
141 log.trace(" alignment " SIZE_FORMAT_HEX, gen_alignment);
142 }
143
144 assert(result_aligned <= max_contraction, "arithmetic is wrong");
145 return result_aligned;
146 }