Mon, 03 Aug 2009 12:59:30 -0700
6865703: G1: Parallelize hot card cache cleanup
Summary: Have the GC worker threads clear the hot card cache in parallel by having each worker thread claim a chunk of the card cache and process the cards in that chunk. The size of the chunks that each thread will claim is determined at VM initialization from the size of the card cache and the number of worker threads.
Reviewed-by: jmasa, tonyp
1 /*
2 * Copyright 2001-2007 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 */
25 inline HeapWord* G1BlockOffsetTable::block_start(const void* addr) {
26 if (addr >= _bottom && addr < _end) {
27 return block_start_unsafe(addr);
28 } else {
29 return NULL;
30 }
31 }
33 inline HeapWord*
34 G1BlockOffsetTable::block_start_const(const void* addr) const {
35 if (addr >= _bottom && addr < _end) {
36 return block_start_unsafe_const(addr);
37 } else {
38 return NULL;
39 }
40 }
42 inline size_t G1BlockOffsetSharedArray::index_for(const void* p) const {
43 char* pc = (char*)p;
44 assert(pc >= (char*)_reserved.start() &&
45 pc < (char*)_reserved.end(),
46 "p not in range.");
47 size_t delta = pointer_delta(pc, _reserved.start(), sizeof(char));
48 size_t result = delta >> LogN;
49 assert(result < _vs.committed_size(), "bad index from address");
50 return result;
51 }
53 inline HeapWord*
54 G1BlockOffsetSharedArray::address_for_index(size_t index) const {
55 assert(index < _vs.committed_size(), "bad index");
56 HeapWord* result = _reserved.start() + (index << LogN_words);
57 assert(result >= _reserved.start() && result < _reserved.end(),
58 "bad address from index");
59 return result;
60 }
62 inline HeapWord*
63 G1BlockOffsetArray::block_at_or_preceding(const void* addr,
64 bool has_max_index,
65 size_t max_index) const {
66 assert(_array->offset_array(0) == 0, "objects can't cross covered areas");
67 size_t index = _array->index_for(addr);
68 // We must make sure that the offset table entry we use is valid. If
69 // "addr" is past the end, start at the last known one and go forward.
70 if (has_max_index) {
71 index = MIN2(index, max_index);
72 }
73 HeapWord* q = _array->address_for_index(index);
75 uint offset = _array->offset_array(index); // Extend u_char to uint.
76 while (offset >= N_words) {
77 // The excess of the offset from N_words indicates a power of Base
78 // to go back by.
79 size_t n_cards_back = BlockOffsetArray::entry_to_cards_back(offset);
80 q -= (N_words * n_cards_back);
81 assert(q >= _sp->bottom(), "Went below bottom!");
82 index -= n_cards_back;
83 offset = _array->offset_array(index);
84 }
85 assert(offset < N_words, "offset too large");
86 q -= offset;
87 return q;
88 }
90 inline HeapWord*
91 G1BlockOffsetArray::
92 forward_to_block_containing_addr_const(HeapWord* q, HeapWord* n,
93 const void* addr) const {
94 if (csp() != NULL) {
95 if (addr >= csp()->top()) return csp()->top();
96 while (n <= addr) {
97 q = n;
98 oop obj = oop(q);
99 if (obj->klass_or_null() == NULL) return q;
100 n += obj->size();
101 }
102 } else {
103 while (n <= addr) {
104 q = n;
105 oop obj = oop(q);
106 if (obj->klass_or_null() == NULL) return q;
107 n += _sp->block_size(q);
108 }
109 }
110 assert(q <= n, "wrong order for q and addr");
111 assert(addr < n, "wrong order for addr and n");
112 return q;
113 }
115 inline HeapWord*
116 G1BlockOffsetArray::forward_to_block_containing_addr(HeapWord* q,
117 const void* addr) {
118 if (oop(q)->klass_or_null() == NULL) return q;
119 HeapWord* n = q + _sp->block_size(q);
120 // In the normal case, where the query "addr" is a card boundary, and the
121 // offset table chunks are the same size as cards, the block starting at
122 // "q" will contain addr, so the test below will fail, and we'll fall
123 // through quickly.
124 if (n <= addr) {
125 q = forward_to_block_containing_addr_slow(q, n, addr);
126 }
127 assert(q <= addr, "wrong order for current and arg");
128 return q;
129 }
131 //////////////////////////////////////////////////////////////////////////
132 // BlockOffsetArrayNonContigSpace inlines
133 //////////////////////////////////////////////////////////////////////////
134 inline void G1BlockOffsetArray::freed(HeapWord* blk_start, HeapWord* blk_end) {
135 // Verify that the BOT shows [blk_start, blk_end) to be one block.
136 verify_single_block(blk_start, blk_end);
137 // adjust _unallocated_block upward or downward
138 // as appropriate
139 if (BlockOffsetArrayUseUnallocatedBlock) {
140 assert(_unallocated_block <= _end,
141 "Inconsistent value for _unallocated_block");
142 if (blk_end >= _unallocated_block && blk_start <= _unallocated_block) {
143 // CMS-specific note: a block abutting _unallocated_block to
144 // its left is being freed, a new block is being added or
145 // we are resetting following a compaction
146 _unallocated_block = blk_start;
147 }
148 }
149 }
151 inline void G1BlockOffsetArray::freed(HeapWord* blk, size_t size) {
152 freed(blk, blk + size);
153 }