Mercurial > hg > graal-compiler
annotate src/share/vm/gc_implementation/parallelScavenge/objectStartArray.cpp @ 1656:4e5661ba9d98
6944166: G1: explicit GCs are not always handled correctly
Summary: G1 was not handling explicit GCs correctly in many ways. It does now. See the CR for the list of improvements contained in this changeset.
Reviewed-by: iveresov, ysr, johnc
author | tonyp |
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date | Mon, 28 Jun 2010 14:13:17 -0400 |
parents | c18cbe5936b8 |
children | f95d63e2154a |
rev | line source |
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0 | 1 /* |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
25 # include "incls/_precompiled.incl" | |
26 # include "incls/_objectStartArray.cpp.incl" | |
27 | |
28 void ObjectStartArray::initialize(MemRegion reserved_region) { | |
29 // We're based on the assumption that we use the same | |
30 // size blocks as the card table. | |
31 assert((int)block_size == (int)CardTableModRefBS::card_size, "Sanity"); | |
32 assert((int)block_size <= 512, "block_size must be less than or equal to 512"); | |
33 | |
34 // Calculate how much space must be reserved | |
35 _reserved_region = reserved_region; | |
36 | |
37 size_t bytes_to_reserve = reserved_region.word_size() / block_size_in_words; | |
38 assert(bytes_to_reserve > 0, "Sanity"); | |
39 | |
40 bytes_to_reserve = | |
41 align_size_up(bytes_to_reserve, os::vm_allocation_granularity()); | |
42 | |
43 // Do not use large-pages for the backing store. The one large page region | |
44 // will be used for the heap proper. | |
45 ReservedSpace backing_store(bytes_to_reserve); | |
46 if (!backing_store.is_reserved()) { | |
47 vm_exit_during_initialization("Could not reserve space for ObjectStartArray"); | |
48 } | |
49 | |
50 // We do not commit any memory initially | |
51 if (!_virtual_space.initialize(backing_store, 0)) { | |
52 vm_exit_during_initialization("Could not commit space for ObjectStartArray"); | |
53 } | |
54 | |
55 _raw_base = (jbyte*)_virtual_space.low_boundary(); | |
56 if (_raw_base == NULL) { | |
57 vm_exit_during_initialization("Could not get raw_base address"); | |
58 } | |
59 | |
60 _offset_base = _raw_base - (size_t(reserved_region.start()) >> block_shift); | |
61 | |
62 _covered_region.set_start(reserved_region.start()); | |
63 _covered_region.set_word_size(0); | |
64 | |
65 _blocks_region.set_start((HeapWord*)_raw_base); | |
66 _blocks_region.set_word_size(0); | |
67 } | |
68 | |
69 void ObjectStartArray::set_covered_region(MemRegion mr) { | |
70 assert(_reserved_region.contains(mr), "MemRegion outside of reserved space"); | |
71 assert(_reserved_region.start() == mr.start(), "Attempt to move covered region"); | |
72 | |
73 HeapWord* low_bound = mr.start(); | |
74 HeapWord* high_bound = mr.end(); | |
75 assert((uintptr_t(low_bound) & (block_size - 1)) == 0, "heap must start at block boundary"); | |
76 assert((uintptr_t(high_bound) & (block_size - 1)) == 0, "heap must end at block boundary"); | |
77 | |
78 size_t requested_blocks_size_in_bytes = mr.word_size() / block_size_in_words; | |
79 | |
80 // Only commit memory in page sized chunks | |
81 requested_blocks_size_in_bytes = | |
82 align_size_up(requested_blocks_size_in_bytes, os::vm_page_size()); | |
83 | |
84 _covered_region = mr; | |
85 | |
86 size_t current_blocks_size_in_bytes = _blocks_region.byte_size(); | |
87 | |
88 if (requested_blocks_size_in_bytes > current_blocks_size_in_bytes) { | |
89 // Expand | |
90 size_t expand_by = requested_blocks_size_in_bytes - current_blocks_size_in_bytes; | |
91 if (!_virtual_space.expand_by(expand_by)) { | |
92 vm_exit_out_of_memory(expand_by, "object start array expansion"); | |
93 } | |
94 // Clear *only* the newly allocated region | |
95 memset(_blocks_region.end(), clean_block, expand_by); | |
96 } | |
97 | |
98 if (requested_blocks_size_in_bytes < current_blocks_size_in_bytes) { | |
99 // Shrink | |
100 size_t shrink_by = current_blocks_size_in_bytes - requested_blocks_size_in_bytes; | |
101 _virtual_space.shrink_by(shrink_by); | |
102 } | |
103 | |
104 _blocks_region.set_word_size(requested_blocks_size_in_bytes / sizeof(HeapWord)); | |
105 | |
106 assert(requested_blocks_size_in_bytes % sizeof(HeapWord) == 0, "Block table not expanded in word sized increment"); | |
107 assert(requested_blocks_size_in_bytes == _blocks_region.byte_size(), "Sanity"); | |
108 assert(block_for_addr(low_bound) == &_raw_base[0], "Checking start of map"); | |
109 assert(block_for_addr(high_bound-1) <= &_raw_base[_blocks_region.byte_size()-1], "Checking end of map"); | |
110 } | |
111 | |
112 void ObjectStartArray::reset() { | |
113 memset(_blocks_region.start(), clean_block, _blocks_region.byte_size()); | |
114 } | |
115 | |
116 | |
117 bool ObjectStartArray::object_starts_in_range(HeapWord* start_addr, | |
118 HeapWord* end_addr) const { | |
119 assert(start_addr <= end_addr, "range is wrong"); | |
120 if (start_addr > end_addr) { | |
121 return false; | |
122 } | |
123 | |
124 jbyte* start_block = block_for_addr(start_addr); | |
125 jbyte* end_block = block_for_addr(end_addr); | |
126 | |
127 for (jbyte* block = start_block; block <= end_block; block++) { | |
128 if (*block != clean_block) { | |
129 return true; | |
130 } | |
131 } | |
132 // No object starts in this slice; verify this using | |
133 // more traditional methods: | |
134 assert(object_start(end_addr - 1) <= start_addr, | |
135 "Oops an object does start in this slice?"); | |
136 return false; | |
137 } |