1 /*
2 * Copyright (c) 2001, 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/parallelScavengeHeap.hpp"
27 #include "gc_implementation/parallelScavenge/psMarkSweepDecorator.hpp"
28 #include "gc_implementation/parallelScavenge/psParallelCompact.hpp"
29 #include "gc_implementation/parallelScavenge/psPermGen.hpp"
30 #include "gc_implementation/shared/gcUtil.hpp"
31 #include "gc_implementation/shared/markSweep.inline.hpp"
32 #include "oops/markOop.inline.hpp"
33
34 PSPermGen::PSPermGen(ReservedSpace rs, size_t alignment,
35 size_t initial_size, size_t min_size, size_t max_size,
36 const char* gen_name, int level) :
37 PSOldGen(rs, alignment, initial_size, min_size, max_size, gen_name, level),
38 _last_used(0)
39 {
40 assert(object_mark_sweep() != NULL, "Sanity");
41
42 object_mark_sweep()->set_allowed_dead_ratio(PermMarkSweepDeadRatio);
43 _avg_size = new AdaptivePaddedAverage(AdaptivePermSizeWeight,
44 PermGenPadding);
45 }
46
47 HeapWord* PSPermGen::allocate_permanent(size_t size) {
48 assert_locked_or_safepoint(Heap_lock);
49 HeapWord* obj = allocate_noexpand(size, false);
50
51 if (obj == NULL) {
52 obj = expand_and_allocate(size, false);
53 }
54
55 return obj;
56 }
57
58 void PSPermGen::compute_new_size(size_t used_before_collection) {
59 // Update our padded average of objects allocated in perm
60 // gen between collections.
61 assert(used_before_collection >= _last_used,
62 "negative allocation amount since last GC?");
63
64 const size_t alloc_since_last_gc = used_before_collection - _last_used;
65 _avg_size->sample(alloc_since_last_gc);
66
67 const size_t current_live = used_in_bytes();
68 // Stash away the current amount live for the next call to this method.
69 _last_used = current_live;
70
71 // We have different alignment constraints than the rest of the heap.
72 const size_t alignment = MAX2(MinPermHeapExpansion,
73 virtual_space()->alignment());
74
75 // Compute the desired size:
76 // The free space is the newly computed padded average,
77 // so the desired size is what's live + the free space.
78 size_t desired_size = current_live + (size_t)_avg_size->padded_average();
79 desired_size = align_size_up(desired_size, alignment);
80
81 // ...and no larger or smaller than our max and min allowed.
82 desired_size = MAX2(MIN2(desired_size, _max_gen_size), _min_gen_size);
83 assert(desired_size <= _max_gen_size, "just checking");
84
85 const size_t size_before = _virtual_space->committed_size();
86
87 if (desired_size == size_before) {
88 // no change, we're done
89 return;
90 }
91
92 {
93 // We'll be growing or shrinking the heap: in either case,
94 // we need to hold a lock.
95 MutexLocker x(ExpandHeap_lock);
96 if (desired_size > size_before) {
97 const size_t change_bytes = desired_size - size_before;
98 const size_t aligned_change_bytes =
99 align_size_up(change_bytes, alignment);
100 expand_by(aligned_change_bytes);
101 } else {
102 // Shrinking
103 const size_t change_bytes =
104 size_before - desired_size;
105 const size_t aligned_change_bytes = align_size_down(change_bytes, alignment);
106 shrink(aligned_change_bytes);
107 }
108 }
109
110 // While this code isn't controlled by AdaptiveSizePolicy, it's
111 // convenient to see all resizing decsions under the same flag.
112 if (PrintAdaptiveSizePolicy) {
113 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
114 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
115
116 gclog_or_tty->print_cr("AdaptiveSizePolicy::perm generation size: "
117 "collection: %d "
118 "(" SIZE_FORMAT ") -> (" SIZE_FORMAT ") ",
119 heap->total_collections(),
120 size_before, _virtual_space->committed_size());
121 }
122 }
123
124
125
126 void PSPermGen::move_and_update(ParCompactionManager* cm) {
127 PSParallelCompact::move_and_update(cm, PSParallelCompact::perm_space_id);
128 }
129
130 void PSPermGen::precompact() {
131 // Reset start array first.
132 _start_array.reset();
133 object_mark_sweep()->precompact();
134 }