Tue, 19 Aug 2014 02:05:49 -0700
8044406: JVM crash with JDK8 (build 1.8.0-b132) with G1 GC
Summary: Fill the last card that has been allocated into with a dummy object
Reviewed-by: tschatzl, mgerdin
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.
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.
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23 */
25 #include "precompiled.hpp"
26 #include "gc_implementation/g1/heapRegion.hpp"
27 #include "gc_implementation/g1/heapRegionSeq.inline.hpp"
28 #include "gc_implementation/g1/heapRegionSet.hpp"
29 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
30 #include "memory/allocation.hpp"
32 // Private
34 uint HeapRegionSeq::find_contiguous_from(uint from, uint num) {
35 uint len = length();
36 assert(num > 1, "use this only for sequences of length 2 or greater");
37 assert(from <= len,
38 err_msg("from: %u should be valid and <= than %u", from, len));
40 uint curr = from;
41 uint first = G1_NULL_HRS_INDEX;
42 uint num_so_far = 0;
43 while (curr < len && num_so_far < num) {
44 if (at(curr)->is_empty()) {
45 if (first == G1_NULL_HRS_INDEX) {
46 first = curr;
47 num_so_far = 1;
48 } else {
49 num_so_far += 1;
50 }
51 } else {
52 first = G1_NULL_HRS_INDEX;
53 num_so_far = 0;
54 }
55 curr += 1;
56 }
57 assert(num_so_far <= num, "post-condition");
58 if (num_so_far == num) {
59 // we found enough space for the humongous object
60 assert(from <= first && first < len, "post-condition");
61 assert(first < curr && (curr - first) == num, "post-condition");
62 for (uint i = first; i < first + num; ++i) {
63 assert(at(i)->is_empty(), "post-condition");
64 }
65 return first;
66 } else {
67 // we failed to find enough space for the humongous object
68 return G1_NULL_HRS_INDEX;
69 }
70 }
72 // Public
74 void HeapRegionSeq::initialize(HeapWord* bottom, HeapWord* end) {
75 assert((uintptr_t) bottom % HeapRegion::GrainBytes == 0,
76 "bottom should be heap region aligned");
77 assert((uintptr_t) end % HeapRegion::GrainBytes == 0,
78 "end should be heap region aligned");
80 _next_search_index = 0;
81 _allocated_length = 0;
83 _regions.initialize(bottom, end, HeapRegion::GrainBytes);
84 }
86 MemRegion HeapRegionSeq::expand_by(HeapWord* old_end,
87 HeapWord* new_end,
88 FreeRegionList* list) {
89 assert(old_end < new_end, "don't call it otherwise");
90 G1CollectedHeap* g1h = G1CollectedHeap::heap();
92 HeapWord* next_bottom = old_end;
93 assert(heap_bottom() <= next_bottom, "invariant");
94 while (next_bottom < new_end) {
95 assert(next_bottom < heap_end(), "invariant");
96 uint index = length();
98 assert(index < max_length(), "otherwise we cannot expand further");
99 if (index == 0) {
100 // We have not allocated any regions so far
101 assert(next_bottom == heap_bottom(), "invariant");
102 } else {
103 // next_bottom should match the end of the last/previous region
104 assert(next_bottom == at(index - 1)->end(), "invariant");
105 }
107 if (index == _allocated_length) {
108 // We have to allocate a new HeapRegion.
109 HeapRegion* new_hr = g1h->new_heap_region(index, next_bottom);
110 if (new_hr == NULL) {
111 // allocation failed, we bail out and return what we have done so far
112 return MemRegion(old_end, next_bottom);
113 }
114 assert(_regions.get_by_index(index) == NULL, "invariant");
115 _regions.set_by_index(index, new_hr);
116 increment_allocated_length();
117 }
118 // Have to increment the length first, otherwise we will get an
119 // assert failure at(index) below.
120 increment_length();
121 HeapRegion* hr = at(index);
122 list->add_as_tail(hr);
124 next_bottom = hr->end();
125 }
126 assert(next_bottom == new_end, "post-condition");
127 return MemRegion(old_end, next_bottom);
128 }
130 uint HeapRegionSeq::free_suffix() {
131 uint res = 0;
132 uint index = length();
133 while (index > 0) {
134 index -= 1;
135 if (!at(index)->is_empty()) {
136 break;
137 }
138 res += 1;
139 }
140 return res;
141 }
143 uint HeapRegionSeq::find_contiguous(uint num) {
144 assert(num > 1, "use this only for sequences of length 2 or greater");
145 assert(_next_search_index <= length(),
146 err_msg("_next_search_index: %u should be valid and <= than %u",
147 _next_search_index, length()));
149 uint start = _next_search_index;
150 uint res = find_contiguous_from(start, num);
151 if (res == G1_NULL_HRS_INDEX && start > 0) {
152 // Try starting from the beginning. If _next_search_index was 0,
153 // no point in doing this again.
154 res = find_contiguous_from(0, num);
155 }
156 if (res != G1_NULL_HRS_INDEX) {
157 assert(res < length(), err_msg("res: %u should be valid", res));
158 _next_search_index = res + num;
159 assert(_next_search_index <= length(),
160 err_msg("_next_search_index: %u should be valid and <= than %u",
161 _next_search_index, length()));
162 }
163 return res;
164 }
166 void HeapRegionSeq::iterate(HeapRegionClosure* blk) const {
167 iterate_from((HeapRegion*) NULL, blk);
168 }
170 void HeapRegionSeq::iterate_from(HeapRegion* hr, HeapRegionClosure* blk) const {
171 uint hr_index = 0;
172 if (hr != NULL) {
173 hr_index = hr->hrs_index();
174 }
176 uint len = length();
177 for (uint i = hr_index; i < len; i += 1) {
178 bool res = blk->doHeapRegion(at(i));
179 if (res) {
180 blk->incomplete();
181 return;
182 }
183 }
184 for (uint i = 0; i < hr_index; i += 1) {
185 bool res = blk->doHeapRegion(at(i));
186 if (res) {
187 blk->incomplete();
188 return;
189 }
190 }
191 }
193 uint HeapRegionSeq::shrink_by(uint num_regions_to_remove) {
194 // Reset this in case it's currently pointing into the regions that
195 // we just removed.
196 _next_search_index = 0;
198 assert(length() > 0, "the region sequence should not be empty");
199 assert(length() <= _allocated_length, "invariant");
200 assert(_allocated_length > 0, "we should have at least one region committed");
201 assert(num_regions_to_remove < length(), "We should never remove all regions");
203 uint i = 0;
204 for (; i < num_regions_to_remove; i++) {
205 HeapRegion* cur = at(length() - 1);
207 if (!cur->is_empty()) {
208 // We have to give up if the region can not be moved
209 break;
210 }
211 assert(!cur->isHumongous(), "Humongous regions should not be empty");
213 decrement_length();
214 }
215 return i;
216 }
218 #ifndef PRODUCT
219 void HeapRegionSeq::verify_optional() {
220 guarantee(length() <= _allocated_length,
221 err_msg("invariant: _length: %u _allocated_length: %u",
222 length(), _allocated_length));
223 guarantee(_allocated_length <= max_length(),
224 err_msg("invariant: _allocated_length: %u _max_length: %u",
225 _allocated_length, max_length()));
226 guarantee(_next_search_index <= length(),
227 err_msg("invariant: _next_search_index: %u _length: %u",
228 _next_search_index, length()));
230 HeapWord* prev_end = heap_bottom();
231 for (uint i = 0; i < _allocated_length; i += 1) {
232 HeapRegion* hr = _regions.get_by_index(i);
233 guarantee(hr != NULL, err_msg("invariant: i: %u", i));
234 guarantee(hr->bottom() == prev_end,
235 err_msg("invariant i: %u "HR_FORMAT" prev_end: "PTR_FORMAT,
236 i, HR_FORMAT_PARAMS(hr), p2i(prev_end)));
237 guarantee(hr->hrs_index() == i,
238 err_msg("invariant: i: %u hrs_index(): %u", i, hr->hrs_index()));
239 if (i < length()) {
240 // Asserts will fire if i is >= _length
241 HeapWord* addr = hr->bottom();
242 guarantee(addr_to_region(addr) == hr, "sanity");
243 guarantee(addr_to_region_unsafe(addr) == hr, "sanity");
244 } else {
245 guarantee(hr->is_empty(), "sanity");
246 guarantee(!hr->isHumongous(), "sanity");
247 // using assert instead of guarantee here since containing_set()
248 // is only available in non-product builds.
249 assert(hr->containing_set() == NULL, "sanity");
250 }
251 if (hr->startsHumongous()) {
252 prev_end = hr->orig_end();
253 } else {
254 prev_end = hr->end();
255 }
256 }
257 for (uint i = _allocated_length; i < max_length(); i += 1) {
258 guarantee(_regions.get_by_index(i) == NULL, err_msg("invariant i: %u", i));
259 }
260 }
261 #endif // PRODUCT