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comparison src/share/vm/gc_implementation/parallelScavenge/asPSOldGen.cpp @ 0:a61af66fc99e jdk7-b24

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author duke
date Sat, 01 Dec 2007 00:00:00 +0000
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1 /*
2 * Copyright 2003-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 # include "incls/_precompiled.incl"
26 # include "incls/_asPSOldGen.cpp.incl"
27
28 // Whereas PSOldGen takes the maximum size of the generation
29 // (which doesn't change in the case of PSOldGen) as a parameter,
30 // ASPSOldGen takes the upper limit on the size of
31 // the generation as a parameter. In ASPSOldGen the
32 // maximum size of the generation can change as the boundary
33 // moves. The "maximum size of the generation" is still a valid
34 // concept since the generation can grow and shrink within that
35 // maximum. There are lots of useful checks that use that
36 // maximum. In PSOldGen the method max_gen_size() returns
37 // _max_gen_size (as set by the PSOldGen constructor). This
38 // is how it always worked. In ASPSOldGen max_gen_size()
39 // returned the size of the reserved space for the generation.
40 // That can change as the boundary moves. Below the limit of
41 // the size of the generation is passed to the PSOldGen constructor
42 // for "_max_gen_size" (have to pass something) but it is not used later.
43 //
44 ASPSOldGen::ASPSOldGen(size_t initial_size,
45 size_t min_size,
46 size_t size_limit,
47 const char* gen_name,
48 int level) :
49 PSOldGen(initial_size, min_size, size_limit, gen_name, level),
50 _gen_size_limit(size_limit)
51
52 {}
53
54 ASPSOldGen::ASPSOldGen(PSVirtualSpace* vs,
55 size_t initial_size,
56 size_t min_size,
57 size_t size_limit,
58 const char* gen_name,
59 int level) :
60 PSOldGen(initial_size, min_size, size_limit, gen_name, level),
61 _gen_size_limit(size_limit)
62
63 {
64 _virtual_space = vs;
65 }
66
67 void ASPSOldGen::reset_after_change() {
68 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
69 (HeapWord*)virtual_space()->high_boundary());
70 post_resize();
71 }
72
73
74 size_t ASPSOldGen::available_for_expansion() {
75 assert(virtual_space()->is_aligned(gen_size_limit()), "not aligned");
76 assert(gen_size_limit() >= virtual_space()->committed_size(), "bad gen size");
77
78 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
79 size_t result = gen_size_limit() - virtual_space()->committed_size();
80 size_t result_aligned = align_size_down(result, heap->old_gen_alignment());
81 return result_aligned;
82 }
83
84 size_t ASPSOldGen::available_for_contraction() {
85 size_t uncommitted_bytes = virtual_space()->uncommitted_size();
86 if (uncommitted_bytes != 0) {
87 return uncommitted_bytes;
88 }
89
90 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
91 const size_t gen_alignment = heap->old_gen_alignment();
92 PSAdaptiveSizePolicy* policy = heap->size_policy();
93 const size_t working_size =
94 used_in_bytes() + (size_t) policy->avg_promoted()->padded_average();
95 const size_t working_aligned = align_size_up(working_size, gen_alignment);
96 const size_t working_or_min = MAX2(working_aligned, min_gen_size());
97 if (working_or_min > reserved().byte_size()) {
98 // If the used or minimum gen size (aligned up) is greater
99 // than the total reserved size, then the space available
100 // for contraction should (after proper alignment) be 0
101 return 0;
102 }
103 const size_t max_contraction =
104 reserved().byte_size() - working_or_min;
105
106 // Use the "increment" fraction instead of the "decrement" fraction
107 // to allow the other gen to expand more aggressively. The
108 // "decrement" fraction is conservative because its intent is to
109 // only reduce the footprint.
110
111 size_t result = policy->promo_increment_aligned_down(max_contraction);
112 // Also adjust for inter-generational alignment
113 size_t result_aligned = align_size_down(result, gen_alignment);
114 if (PrintAdaptiveSizePolicy && Verbose) {
115 gclog_or_tty->print_cr("\nASPSOldGen::available_for_contraction:"
116 " %d K / 0x%x", result_aligned/K, result_aligned);
117 gclog_or_tty->print_cr(" reserved().byte_size() %d K / 0x%x ",
118 reserved().byte_size()/K, reserved().byte_size());
119 size_t working_promoted = (size_t) policy->avg_promoted()->padded_average();
120 gclog_or_tty->print_cr(" padded promoted %d K / 0x%x",
121 working_promoted/K, working_promoted);
122 gclog_or_tty->print_cr(" used %d K / 0x%x",
123 used_in_bytes()/K, used_in_bytes());
124 gclog_or_tty->print_cr(" min_gen_size() %d K / 0x%x",
125 min_gen_size()/K, min_gen_size());
126 gclog_or_tty->print_cr(" max_contraction %d K / 0x%x",
127 max_contraction/K, max_contraction);
128 gclog_or_tty->print_cr(" without alignment %d K / 0x%x",
129 policy->promo_increment(max_contraction)/K,
130 policy->promo_increment(max_contraction));
131 gclog_or_tty->print_cr(" alignment 0x%x", gen_alignment);
132 }
133 assert(result_aligned <= max_contraction, "arithmetic is wrong");
134 return result_aligned;
135 }