Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/g1/heapRegionSeq.cpp @ 4784:02838862dec8
7121623: G1: always be able to reliably calculate the length of a forwarded chunked array
Summary: Store the "next chunk start index" in the length field of the to-space object, instead of the from-space object, so that we can always reliably read the size of all from-space objects.
Reviewed-by: johnc, ysr, jmasa
author | tonyp |
---|---|
date | Sat, 07 Jan 2012 00:43:59 -0500 |
parents | c3f1170908be |
children | 720b6a76dd9d |
rev | line source |
---|---|
342 | 1 /* |
2133
2250ee17e258
7007068: G1: refine the BOT during evac failure handling
tonyp
parents:
1972
diff
changeset
|
2 * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved. |
342 | 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 * | |
1552
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
960
diff
changeset
|
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
960
diff
changeset
|
20 * or visit www.oracle.com if you need additional information or have any |
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
960
diff
changeset
|
21 * questions. |
342 | 22 * |
23 */ | |
24 | |
1972 | 25 #include "precompiled.hpp" |
3766 | 26 #include "gc_implementation/g1/heapRegion.hpp" |
27 #include "gc_implementation/g1/heapRegionSeq.inline.hpp" | |
28 #include "gc_implementation/g1/heapRegionSets.hpp" | |
1972 | 29 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp" |
30 #include "memory/allocation.hpp" | |
342 | 31 |
3766 | 32 // Private |
342 | 33 |
3766 | 34 size_t HeapRegionSeq::find_contiguous_from(size_t from, size_t num) { |
35 size_t len = length(); | |
36 assert(num > 1, "use this only for sequences of length 2 or greater"); | |
37 assert(from <= len, | |
38 err_msg("from: "SIZE_FORMAT" should be valid and <= than "SIZE_FORMAT, | |
39 from, len)); | |
342 | 40 |
3766 | 41 size_t curr = from; |
42 size_t first = G1_NULL_HRS_INDEX; | |
2152 | 43 size_t num_so_far = 0; |
3766 | 44 while (curr < len && num_so_far < num) { |
45 if (at(curr)->is_empty()) { | |
46 if (first == G1_NULL_HRS_INDEX) { | |
2152 | 47 first = curr; |
48 num_so_far = 1; | |
49 } else { | |
50 num_so_far += 1; | |
51 } | |
52 } else { | |
3766 | 53 first = G1_NULL_HRS_INDEX; |
2152 | 54 num_so_far = 0; |
55 } | |
56 curr += 1; | |
57 } | |
58 assert(num_so_far <= num, "post-condition"); | |
59 if (num_so_far == num) { | |
2361 | 60 // we found enough space for the humongous object |
3766 | 61 assert(from <= first && first < len, "post-condition"); |
62 assert(first < curr && (curr - first) == num, "post-condition"); | |
63 for (size_t i = first; i < first + num; ++i) { | |
64 assert(at(i)->is_empty(), "post-condition"); | |
2152 | 65 } |
66 return first; | |
67 } else { | |
68 // we failed to find enough space for the humongous object | |
3766 | 69 return G1_NULL_HRS_INDEX; |
2152 | 70 } |
71 } | |
72 | |
3766 | 73 // Public |
74 | |
75 void HeapRegionSeq::initialize(HeapWord* bottom, HeapWord* end, | |
76 size_t max_length) { | |
77 assert((size_t) bottom % HeapRegion::GrainBytes == 0, | |
78 "bottom should be heap region aligned"); | |
79 assert((size_t) end % HeapRegion::GrainBytes == 0, | |
80 "end should be heap region aligned"); | |
81 | |
82 _length = 0; | |
83 _heap_bottom = bottom; | |
84 _heap_end = end; | |
85 _region_shift = HeapRegion::LogOfHRGrainBytes; | |
86 _next_search_index = 0; | |
87 _allocated_length = 0; | |
88 _max_length = max_length; | |
89 | |
90 _regions = NEW_C_HEAP_ARRAY(HeapRegion*, max_length); | |
91 memset(_regions, 0, max_length * sizeof(HeapRegion*)); | |
92 _regions_biased = _regions - ((size_t) bottom >> _region_shift); | |
93 | |
94 assert(&_regions[0] == &_regions_biased[addr_to_index_biased(bottom)], | |
95 "bottom should be included in the region with index 0"); | |
96 } | |
97 | |
98 MemRegion HeapRegionSeq::expand_by(HeapWord* old_end, | |
99 HeapWord* new_end, | |
100 FreeRegionList* list) { | |
101 assert(old_end < new_end, "don't call it otherwise"); | |
102 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
103 | |
104 HeapWord* next_bottom = old_end; | |
105 assert(_heap_bottom <= next_bottom, "invariant"); | |
106 while (next_bottom < new_end) { | |
107 assert(next_bottom < _heap_end, "invariant"); | |
108 size_t index = length(); | |
2152 | 109 |
3766 | 110 assert(index < _max_length, "otherwise we cannot expand further"); |
111 if (index == 0) { | |
112 // We have not allocated any regions so far | |
113 assert(next_bottom == _heap_bottom, "invariant"); | |
114 } else { | |
115 // next_bottom should match the end of the last/previous region | |
116 assert(next_bottom == at(index - 1)->end(), "invariant"); | |
117 } | |
118 | |
119 if (index == _allocated_length) { | |
120 // We have to allocate a new HeapRegion. | |
121 HeapRegion* new_hr = g1h->new_heap_region(index, next_bottom); | |
122 if (new_hr == NULL) { | |
123 // allocation failed, we bail out and return what we have done so far | |
124 return MemRegion(old_end, next_bottom); | |
125 } | |
126 assert(_regions[index] == NULL, "invariant"); | |
127 _regions[index] = new_hr; | |
128 increment_length(&_allocated_length); | |
129 } | |
130 // Have to increment the length first, otherwise we will get an | |
131 // assert failure at(index) below. | |
132 increment_length(&_length); | |
133 HeapRegion* hr = at(index); | |
134 list->add_as_tail(hr); | |
135 | |
136 next_bottom = hr->end(); | |
2152 | 137 } |
3766 | 138 assert(next_bottom == new_end, "post-condition"); |
139 return MemRegion(old_end, next_bottom); | |
140 } | |
141 | |
142 size_t HeapRegionSeq::free_suffix() { | |
143 size_t res = 0; | |
144 size_t index = length(); | |
145 while (index > 0) { | |
146 index -= 1; | |
147 if (!at(index)->is_empty()) { | |
148 break; | |
149 } | |
150 res += 1; | |
2152 | 151 } |
342 | 152 return res; |
153 } | |
154 | |
3766 | 155 size_t HeapRegionSeq::find_contiguous(size_t num) { |
156 assert(num > 1, "use this only for sequences of length 2 or greater"); | |
157 assert(_next_search_index <= length(), | |
158 err_msg("_next_search_indeex: "SIZE_FORMAT" " | |
159 "should be valid and <= than "SIZE_FORMAT, | |
160 _next_search_index, length())); | |
161 | |
162 size_t start = _next_search_index; | |
163 size_t res = find_contiguous_from(start, num); | |
164 if (res == G1_NULL_HRS_INDEX && start > 0) { | |
165 // Try starting from the beginning. If _next_search_index was 0, | |
166 // no point in doing this again. | |
167 res = find_contiguous_from(0, num); | |
168 } | |
169 if (res != G1_NULL_HRS_INDEX) { | |
170 assert(res < length(), | |
171 err_msg("res: "SIZE_FORMAT" should be valid", res)); | |
172 _next_search_index = res + num; | |
173 assert(_next_search_index <= length(), | |
174 err_msg("_next_search_indeex: "SIZE_FORMAT" " | |
175 "should be valid and <= than "SIZE_FORMAT, | |
176 _next_search_index, length())); | |
177 } | |
178 return res; | |
342 | 179 } |
180 | |
3766 | 181 void HeapRegionSeq::iterate(HeapRegionClosure* blk) const { |
182 iterate_from((HeapRegion*) NULL, blk); | |
183 } | |
342 | 184 |
3766 | 185 void HeapRegionSeq::iterate_from(HeapRegion* hr, HeapRegionClosure* blk) const { |
186 size_t hr_index = 0; | |
187 if (hr != NULL) { | |
188 hr_index = (size_t) hr->hrs_index(); | |
342 | 189 } |
3766 | 190 |
191 size_t len = length(); | |
192 for (size_t i = hr_index; i < len; i += 1) { | |
193 bool res = blk->doHeapRegion(at(i)); | |
342 | 194 if (res) { |
195 blk->incomplete(); | |
196 return; | |
197 } | |
198 } | |
3766 | 199 for (size_t i = 0; i < hr_index; i += 1) { |
200 bool res = blk->doHeapRegion(at(i)); | |
342 | 201 if (res) { |
202 blk->incomplete(); | |
203 return; | |
204 } | |
205 } | |
206 } | |
207 | |
208 MemRegion HeapRegionSeq::shrink_by(size_t shrink_bytes, | |
3766 | 209 size_t* num_regions_deleted) { |
2152 | 210 // Reset this in case it's currently pointing into the regions that |
211 // we just removed. | |
3766 | 212 _next_search_index = 0; |
2152 | 213 |
342 | 214 assert(shrink_bytes % os::vm_page_size() == 0, "unaligned"); |
215 assert(shrink_bytes % HeapRegion::GrainBytes == 0, "unaligned"); | |
3766 | 216 assert(length() > 0, "the region sequence should not be empty"); |
217 assert(length() <= _allocated_length, "invariant"); | |
218 assert(_allocated_length > 0, "we should have at least one region committed"); | |
342 | 219 |
3766 | 220 // around the loop, i will be the next region to be removed |
221 size_t i = length() - 1; | |
222 assert(i > 0, "we should never remove all regions"); | |
223 // [last_start, end) is the MemRegion that covers the regions we will remove. | |
224 HeapWord* end = at(i)->end(); | |
342 | 225 HeapWord* last_start = end; |
3766 | 226 *num_regions_deleted = 0; |
227 while (shrink_bytes > 0) { | |
228 HeapRegion* cur = at(i); | |
229 // We should leave the humongous regions where they are. | |
230 if (cur->isHumongous()) break; | |
231 // We should stop shrinking if we come across a non-empty region. | |
342 | 232 if (!cur->is_empty()) break; |
3766 | 233 |
234 i -= 1; | |
235 *num_regions_deleted += 1; | |
342 | 236 shrink_bytes -= cur->capacity(); |
237 last_start = cur->bottom(); | |
3766 | 238 decrement_length(&_length); |
239 // We will reclaim the HeapRegion. _allocated_length should be | |
240 // covering this index. So, even though we removed the region from | |
241 // the active set by decreasing _length, we still have it | |
242 // available in the future if we need to re-use it. | |
243 assert(i > 0, "we should never remove all regions"); | |
244 assert(length() > 0, "we should never remove all regions"); | |
342 | 245 } |
246 return MemRegion(last_start, end); | |
247 } | |
248 | |
3766 | 249 #ifndef PRODUCT |
250 void HeapRegionSeq::verify_optional() { | |
251 guarantee(_length <= _allocated_length, | |
252 err_msg("invariant: _length: "SIZE_FORMAT" " | |
253 "_allocated_length: "SIZE_FORMAT, | |
254 _length, _allocated_length)); | |
255 guarantee(_allocated_length <= _max_length, | |
256 err_msg("invariant: _allocated_length: "SIZE_FORMAT" " | |
257 "_max_length: "SIZE_FORMAT, | |
258 _allocated_length, _max_length)); | |
259 guarantee(_next_search_index <= _length, | |
260 err_msg("invariant: _next_search_index: "SIZE_FORMAT" " | |
261 "_length: "SIZE_FORMAT, | |
262 _next_search_index, _length)); | |
263 | |
264 HeapWord* prev_end = _heap_bottom; | |
265 for (size_t i = 0; i < _allocated_length; i += 1) { | |
266 HeapRegion* hr = _regions[i]; | |
267 guarantee(hr != NULL, err_msg("invariant: i: "SIZE_FORMAT, i)); | |
268 guarantee(hr->bottom() == prev_end, | |
269 err_msg("invariant i: "SIZE_FORMAT" "HR_FORMAT" " | |
270 "prev_end: "PTR_FORMAT, | |
271 i, HR_FORMAT_PARAMS(hr), prev_end)); | |
272 guarantee(hr->hrs_index() == i, | |
273 err_msg("invariant: i: "SIZE_FORMAT" hrs_index(): "SIZE_FORMAT, | |
274 i, hr->hrs_index())); | |
275 if (i < _length) { | |
276 // Asserts will fire if i is >= _length | |
277 HeapWord* addr = hr->bottom(); | |
278 guarantee(addr_to_region(addr) == hr, "sanity"); | |
279 guarantee(addr_to_region_unsafe(addr) == hr, "sanity"); | |
280 } else { | |
281 guarantee(hr->is_empty(), "sanity"); | |
282 guarantee(!hr->isHumongous(), "sanity"); | |
283 // using assert instead of guarantee here since containing_set() | |
284 // is only available in non-product builds. | |
285 assert(hr->containing_set() == NULL, "sanity"); | |
286 } | |
287 if (hr->startsHumongous()) { | |
288 prev_end = hr->orig_end(); | |
289 } else { | |
290 prev_end = hr->end(); | |
291 } | |
342 | 292 } |
3766 | 293 for (size_t i = _allocated_length; i < _max_length; i += 1) { |
294 guarantee(_regions[i] == NULL, err_msg("invariant i: "SIZE_FORMAT, i)); | |
295 } | |
342 | 296 } |
3766 | 297 #endif // PRODUCT |