Tue, 05 May 2009 22:15:35 -0700
6833576: G1: assert illegal index, growableArray.hpp:186
Summary: The code that calculates the heap region index for an object address incorrectly used signed arithmetic.
Reviewed-by: jcoomes, ysr
1 /*
2 * Copyright 2001-2009 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.
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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
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23 */
25 #include "incls/_precompiled.incl"
26 #include "incls/_heapRegionSeq.cpp.incl"
28 // Local to this file.
30 static int orderRegions(HeapRegion** hr1p, HeapRegion** hr2p) {
31 if ((*hr1p)->end() <= (*hr2p)->bottom()) return -1;
32 else if ((*hr2p)->end() <= (*hr1p)->bottom()) return 1;
33 else if (*hr1p == *hr2p) return 0;
34 else {
35 assert(false, "We should never compare distinct overlapping regions.");
36 }
37 return 0;
38 }
40 HeapRegionSeq::HeapRegionSeq(const size_t max_size) :
41 _alloc_search_start(0),
42 // The line below is the worst bit of C++ hackery I've ever written
43 // (Detlefs, 11/23). You should think of it as equivalent to
44 // "_regions(100, true)": initialize the growable array and inform it
45 // that it should allocate its elem array(s) on the C heap. The first
46 // argument, however, is actually a comma expression (new-expr, 100).
47 // The purpose of the new_expr is to inform the growable array that it
48 // is *already* allocated on the C heap: it uses the placement syntax to
49 // keep it from actually doing any allocation.
50 _regions((ResourceObj::operator new (sizeof(GrowableArray<HeapRegion*>),
51 (void*)&_regions,
52 ResourceObj::C_HEAP),
53 (int)max_size),
54 true),
55 _next_rr_candidate(0),
56 _seq_bottom(NULL)
57 {}
59 // Private methods.
61 HeapWord*
62 HeapRegionSeq::alloc_obj_from_region_index(int ind, size_t word_size) {
63 assert(G1CollectedHeap::isHumongous(word_size),
64 "Allocation size should be humongous");
65 int cur = ind;
66 int first = cur;
67 size_t sumSizes = 0;
68 while (cur < _regions.length() && sumSizes < word_size) {
69 // Loop invariant:
70 // For all i in [first, cur):
71 // _regions.at(i)->is_empty()
72 // && _regions.at(i) is contiguous with its predecessor, if any
73 // && sumSizes is the sum of the sizes of the regions in the interval
74 // [first, cur)
75 HeapRegion* curhr = _regions.at(cur);
76 if (curhr->is_empty()
77 && (first == cur
78 || (_regions.at(cur-1)->end() ==
79 curhr->bottom()))) {
80 sumSizes += curhr->capacity() / HeapWordSize;
81 } else {
82 first = cur + 1;
83 sumSizes = 0;
84 }
85 cur++;
86 }
87 if (sumSizes >= word_size) {
88 _alloc_search_start = cur;
89 // Mark the allocated regions as allocated.
90 bool zf = G1CollectedHeap::heap()->allocs_are_zero_filled();
91 HeapRegion* first_hr = _regions.at(first);
92 for (int i = first; i < cur; i++) {
93 HeapRegion* hr = _regions.at(i);
94 if (zf)
95 hr->ensure_zero_filled();
96 {
97 MutexLockerEx x(ZF_mon, Mutex::_no_safepoint_check_flag);
98 hr->set_zero_fill_allocated();
99 }
100 size_t sz = hr->capacity() / HeapWordSize;
101 HeapWord* tmp = hr->allocate(sz);
102 assert(tmp != NULL, "Humongous allocation failure");
103 MemRegion mr = MemRegion(tmp, sz);
104 CollectedHeap::fill_with_object(mr);
105 hr->declare_filled_region_to_BOT(mr);
106 if (i == first) {
107 first_hr->set_startsHumongous();
108 } else {
109 assert(i > first, "sanity");
110 hr->set_continuesHumongous(first_hr);
111 }
112 }
113 HeapWord* first_hr_bot = first_hr->bottom();
114 HeapWord* obj_end = first_hr_bot + word_size;
115 first_hr->set_top(obj_end);
116 return first_hr_bot;
117 } else {
118 // If we started from the beginning, we want to know why we can't alloc.
119 return NULL;
120 }
121 }
123 void HeapRegionSeq::print_empty_runs() {
124 int empty_run = 0;
125 int n_empty = 0;
126 int empty_run_start;
127 for (int i = 0; i < _regions.length(); i++) {
128 HeapRegion* r = _regions.at(i);
129 if (r->continuesHumongous()) continue;
130 if (r->is_empty()) {
131 assert(!r->isHumongous(), "H regions should not be empty.");
132 if (empty_run == 0) empty_run_start = i;
133 empty_run++;
134 n_empty++;
135 } else {
136 if (empty_run > 0) {
137 gclog_or_tty->print(" %d:%d", empty_run_start, empty_run);
138 empty_run = 0;
139 }
140 }
141 }
142 if (empty_run > 0) {
143 gclog_or_tty->print(" %d:%d", empty_run_start, empty_run);
144 }
145 gclog_or_tty->print_cr(" [tot = %d]", n_empty);
146 }
148 int HeapRegionSeq::find(HeapRegion* hr) {
149 // FIXME: optimized for adjacent regions of fixed size.
150 int ind = hr->hrs_index();
151 if (ind != -1) {
152 assert(_regions.at(ind) == hr, "Mismatch");
153 }
154 return ind;
155 }
158 // Public methods.
160 void HeapRegionSeq::insert(HeapRegion* hr) {
161 assert(!_regions.is_full(), "Too many elements in HeapRegionSeq");
162 if (_regions.length() == 0
163 || _regions.top()->end() <= hr->bottom()) {
164 hr->set_hrs_index(_regions.length());
165 _regions.append(hr);
166 } else {
167 _regions.append(hr);
168 _regions.sort(orderRegions);
169 for (int i = 0; i < _regions.length(); i++) {
170 _regions.at(i)->set_hrs_index(i);
171 }
172 }
173 char* bot = (char*)_regions.at(0)->bottom();
174 if (_seq_bottom == NULL || bot < _seq_bottom) _seq_bottom = bot;
175 }
177 size_t HeapRegionSeq::length() {
178 return _regions.length();
179 }
181 size_t HeapRegionSeq::free_suffix() {
182 size_t res = 0;
183 int first = _regions.length() - 1;
184 int cur = first;
185 while (cur >= 0 &&
186 (_regions.at(cur)->is_empty()
187 && (first == cur
188 || (_regions.at(cur+1)->bottom() ==
189 _regions.at(cur)->end())))) {
190 res++;
191 cur--;
192 }
193 return res;
194 }
196 HeapWord* HeapRegionSeq::obj_allocate(size_t word_size) {
197 int cur = _alloc_search_start;
198 // Make sure "cur" is a valid index.
199 assert(cur >= 0, "Invariant.");
200 HeapWord* res = alloc_obj_from_region_index(cur, word_size);
201 if (res == NULL)
202 res = alloc_obj_from_region_index(0, word_size);
203 return res;
204 }
206 void HeapRegionSeq::iterate(HeapRegionClosure* blk) {
207 iterate_from((HeapRegion*)NULL, blk);
208 }
210 // The first argument r is the heap region at which iteration begins.
211 // This operation runs fastest when r is NULL, or the heap region for
212 // which a HeapRegionClosure most recently returned true, or the
213 // heap region immediately to its right in the sequence. In all
214 // other cases a linear search is required to find the index of r.
216 void HeapRegionSeq::iterate_from(HeapRegion* r, HeapRegionClosure* blk) {
218 // :::: FIXME ::::
219 // Static cache value is bad, especially when we start doing parallel
220 // remembered set update. For now just don't cache anything (the
221 // code in the def'd out blocks).
223 #if 0
224 static int cached_j = 0;
225 #endif
226 int len = _regions.length();
227 int j = 0;
228 // Find the index of r.
229 if (r != NULL) {
230 #if 0
231 assert(cached_j >= 0, "Invariant.");
232 if ((cached_j < len) && (r == _regions.at(cached_j))) {
233 j = cached_j;
234 } else if ((cached_j + 1 < len) && (r == _regions.at(cached_j + 1))) {
235 j = cached_j + 1;
236 } else {
237 j = find(r);
238 #endif
239 if (j < 0) {
240 j = 0;
241 }
242 #if 0
243 }
244 #endif
245 }
246 int i;
247 for (i = j; i < len; i += 1) {
248 int res = blk->doHeapRegion(_regions.at(i));
249 if (res) {
250 #if 0
251 cached_j = i;
252 #endif
253 blk->incomplete();
254 return;
255 }
256 }
257 for (i = 0; i < j; i += 1) {
258 int res = blk->doHeapRegion(_regions.at(i));
259 if (res) {
260 #if 0
261 cached_j = i;
262 #endif
263 blk->incomplete();
264 return;
265 }
266 }
267 }
269 void HeapRegionSeq::iterate_from(int idx, HeapRegionClosure* blk) {
270 int len = _regions.length();
271 int i;
272 for (i = idx; i < len; i++) {
273 if (blk->doHeapRegion(_regions.at(i))) {
274 blk->incomplete();
275 return;
276 }
277 }
278 for (i = 0; i < idx; i++) {
279 if (blk->doHeapRegion(_regions.at(i))) {
280 blk->incomplete();
281 return;
282 }
283 }
284 }
286 MemRegion HeapRegionSeq::shrink_by(size_t shrink_bytes,
287 size_t& num_regions_deleted) {
288 assert(shrink_bytes % os::vm_page_size() == 0, "unaligned");
289 assert(shrink_bytes % HeapRegion::GrainBytes == 0, "unaligned");
291 if (_regions.length() == 0) {
292 num_regions_deleted = 0;
293 return MemRegion();
294 }
295 int j = _regions.length() - 1;
296 HeapWord* end = _regions.at(j)->end();
297 HeapWord* last_start = end;
298 while (j >= 0 && shrink_bytes > 0) {
299 HeapRegion* cur = _regions.at(j);
300 // We have to leave humongous regions where they are,
301 // and work around them.
302 if (cur->isHumongous()) {
303 return MemRegion(last_start, end);
304 }
305 cur->reset_zero_fill();
306 assert(cur == _regions.top(), "Should be top");
307 if (!cur->is_empty()) break;
308 shrink_bytes -= cur->capacity();
309 num_regions_deleted++;
310 _regions.pop();
311 last_start = cur->bottom();
312 // We need to delete these somehow, but can't currently do so here: if
313 // we do, the ZF thread may still access the deleted region. We'll
314 // leave this here as a reminder that we have to do something about
315 // this.
316 // delete cur;
317 j--;
318 }
319 return MemRegion(last_start, end);
320 }
323 class PrintHeapRegionClosure : public HeapRegionClosure {
324 public:
325 bool doHeapRegion(HeapRegion* r) {
326 gclog_or_tty->print(PTR_FORMAT ":", r);
327 r->print();
328 return false;
329 }
330 };
332 void HeapRegionSeq::print() {
333 PrintHeapRegionClosure cl;
334 iterate(&cl);
335 }