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.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
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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.
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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//
51ASPSOldGen::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
60ASPSOldGen::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
72void 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
82void ASPSOldGen::reset_after_change() {
83  _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
84                        (HeapWord*)virtual_space()->high_boundary());
85  post_resize();
86}
87
88
89size_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
99size_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}
147