Thu, 21 Aug 2014 16:44:41 +0200
8055098: WB API should be extended to provide information about size and age of object.
Summary: Extend the WhiteBox API to provide information about the size and age of objects. Further add a mechanism to trigger a young GC.
Reviewed-by: tschatzl, sjohanss
Contributed-by: Leonid Mesnik <leonid.mesnik@oracle.com>
1 /*
2 * Copyright (c) 2001, 2014, 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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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).
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23 */
25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1BLOCKOFFSETTABLE_INLINE_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1BLOCKOFFSETTABLE_INLINE_HPP
28 #include "gc_implementation/g1/g1BlockOffsetTable.hpp"
29 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
30 #include "gc_implementation/g1/heapRegion.inline.hpp"
31 #include "memory/space.hpp"
33 inline HeapWord* G1BlockOffsetTable::block_start(const void* addr) {
34 if (addr >= _bottom && addr < _end) {
35 return block_start_unsafe(addr);
36 } else {
37 return NULL;
38 }
39 }
41 inline HeapWord*
42 G1BlockOffsetTable::block_start_const(const void* addr) const {
43 if (addr >= _bottom && addr < _end) {
44 return block_start_unsafe_const(addr);
45 } else {
46 return NULL;
47 }
48 }
50 #define check_index(index, msg) \
51 assert((index) < (_reserved.word_size() >> LogN_words), \
52 err_msg("%s - index: "SIZE_FORMAT", _vs.committed_size: "SIZE_FORMAT, \
53 msg, (index), (_reserved.word_size() >> LogN_words))); \
54 assert(G1CollectedHeap::heap()->is_in_exact(address_for_index_raw(index)), \
55 err_msg("Index "SIZE_FORMAT" corresponding to "PTR_FORMAT \
56 " (%u) is not in committed area.", \
57 (index), \
58 p2i(address_for_index_raw(index)), \
59 G1CollectedHeap::heap()->addr_to_region(address_for_index_raw(index))));
61 u_char G1BlockOffsetSharedArray::offset_array(size_t index) const {
62 check_index(index, "index out of range");
63 return _offset_array[index];
64 }
66 void G1BlockOffsetSharedArray::set_offset_array(size_t index, u_char offset) {
67 check_index(index, "index out of range");
68 set_offset_array_raw(index, offset);
69 }
71 void G1BlockOffsetSharedArray::set_offset_array(size_t index, HeapWord* high, HeapWord* low) {
72 check_index(index, "index out of range");
73 assert(high >= low, "addresses out of order");
74 size_t offset = pointer_delta(high, low);
75 check_offset(offset, "offset too large");
76 set_offset_array(index, (u_char)offset);
77 }
79 void G1BlockOffsetSharedArray::set_offset_array(size_t left, size_t right, u_char offset) {
80 check_index(right, "right index out of range");
81 assert(left <= right, "indexes out of order");
82 size_t num_cards = right - left + 1;
83 if (UseMemSetInBOT) {
84 memset(&_offset_array[left], offset, num_cards);
85 } else {
86 size_t i = left;
87 const size_t end = i + num_cards;
88 for (; i < end; i++) {
89 _offset_array[i] = offset;
90 }
91 }
92 }
94 void G1BlockOffsetSharedArray::check_offset_array(size_t index, HeapWord* high, HeapWord* low) const {
95 check_index(index, "index out of range");
96 assert(high >= low, "addresses out of order");
97 check_offset(pointer_delta(high, low), "offset too large");
98 assert(_offset_array[index] == pointer_delta(high, low), "Wrong offset");
99 }
101 // Variant of index_for that does not check the index for validity.
102 inline size_t G1BlockOffsetSharedArray::index_for_raw(const void* p) const {
103 return pointer_delta((char*)p, _reserved.start(), sizeof(char)) >> LogN;
104 }
106 inline size_t G1BlockOffsetSharedArray::index_for(const void* p) const {
107 char* pc = (char*)p;
108 assert(pc >= (char*)_reserved.start() &&
109 pc < (char*)_reserved.end(),
110 err_msg("p (" PTR_FORMAT ") not in reserved [" PTR_FORMAT ", " PTR_FORMAT ")",
111 p2i(p), p2i(_reserved.start()), p2i(_reserved.end())));
112 size_t result = index_for_raw(p);
113 check_index(result, "bad index from address");
114 return result;
115 }
117 inline HeapWord*
118 G1BlockOffsetSharedArray::address_for_index(size_t index) const {
119 check_index(index, "index out of range");
120 HeapWord* result = address_for_index_raw(index);
121 assert(result >= _reserved.start() && result < _reserved.end(),
122 err_msg("bad address from index result " PTR_FORMAT
123 " _reserved.start() " PTR_FORMAT " _reserved.end() "
124 PTR_FORMAT,
125 p2i(result), p2i(_reserved.start()), p2i(_reserved.end())));
126 return result;
127 }
129 #undef check_index
131 inline size_t
132 G1BlockOffsetArray::block_size(const HeapWord* p) const {
133 return gsp()->block_size(p);
134 }
136 inline HeapWord*
137 G1BlockOffsetArray::block_at_or_preceding(const void* addr,
138 bool has_max_index,
139 size_t max_index) const {
140 assert(_array->offset_array(0) == 0, "objects can't cross covered areas");
141 size_t index = _array->index_for(addr);
142 // We must make sure that the offset table entry we use is valid. If
143 // "addr" is past the end, start at the last known one and go forward.
144 if (has_max_index) {
145 index = MIN2(index, max_index);
146 }
147 HeapWord* q = _array->address_for_index(index);
149 uint offset = _array->offset_array(index); // Extend u_char to uint.
150 while (offset >= N_words) {
151 // The excess of the offset from N_words indicates a power of Base
152 // to go back by.
153 size_t n_cards_back = BlockOffsetArray::entry_to_cards_back(offset);
154 q -= (N_words * n_cards_back);
155 assert(q >= gsp()->bottom(), "Went below bottom!");
156 index -= n_cards_back;
157 offset = _array->offset_array(index);
158 }
159 assert(offset < N_words, "offset too large");
160 q -= offset;
161 return q;
162 }
164 inline HeapWord*
165 G1BlockOffsetArray::
166 forward_to_block_containing_addr_const(HeapWord* q, HeapWord* n,
167 const void* addr) const {
168 if (addr >= gsp()->top()) return gsp()->top();
169 while (n <= addr) {
170 q = n;
171 oop obj = oop(q);
172 if (obj->klass_or_null() == NULL) return q;
173 n += block_size(q);
174 }
175 assert(q <= n, "wrong order for q and addr");
176 assert(addr < n, "wrong order for addr and n");
177 return q;
178 }
180 inline HeapWord*
181 G1BlockOffsetArray::forward_to_block_containing_addr(HeapWord* q,
182 const void* addr) {
183 if (oop(q)->klass_or_null() == NULL) return q;
184 HeapWord* n = q + block_size(q);
185 // In the normal case, where the query "addr" is a card boundary, and the
186 // offset table chunks are the same size as cards, the block starting at
187 // "q" will contain addr, so the test below will fail, and we'll fall
188 // through quickly.
189 if (n <= addr) {
190 q = forward_to_block_containing_addr_slow(q, n, addr);
191 }
192 assert(q <= addr, "wrong order for current and arg");
193 return q;
194 }
196 //////////////////////////////////////////////////////////////////////////
197 // BlockOffsetArrayNonContigSpace inlines
198 //////////////////////////////////////////////////////////////////////////
199 inline void G1BlockOffsetArray::freed(HeapWord* blk_start, HeapWord* blk_end) {
200 // Verify that the BOT shows [blk_start, blk_end) to be one block.
201 verify_single_block(blk_start, blk_end);
202 // adjust _unallocated_block upward or downward
203 // as appropriate
204 if (BlockOffsetArrayUseUnallocatedBlock) {
205 assert(_unallocated_block <= _end,
206 "Inconsistent value for _unallocated_block");
207 if (blk_end >= _unallocated_block && blk_start <= _unallocated_block) {
208 // CMS-specific note: a block abutting _unallocated_block to
209 // its left is being freed, a new block is being added or
210 // we are resetting following a compaction
211 _unallocated_block = blk_start;
212 }
213 }
214 }
216 inline void G1BlockOffsetArray::freed(HeapWord* blk, size_t size) {
217 freed(blk, blk + size);
218 }
220 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1BLOCKOFFSETTABLE_INLINE_HPP