Tue, 19 May 2015 15:49:27 +0200
8061715: gc/g1/TestShrinkAuxiliaryData15.java fails with java.lang.RuntimeException: heap decommit failed - after > before
Summary: added WhiteBox methods to count regions and exact aux data sizes
Reviewed-by: jwilhelm, brutisso
1 /*
2 * Copyright (c) 2011, 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.
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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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
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23 */
25 #include "precompiled.hpp"
26 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
27 #include "gc_implementation/g1/heapRegionRemSet.hpp"
28 #include "gc_implementation/g1/heapRegionSet.inline.hpp"
30 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
32 uint FreeRegionList::_unrealistically_long_length = 0;
34 void HeapRegionSetBase::fill_in_ext_msg(hrs_ext_msg* msg, const char* message) {
35 msg->append("[%s] %s ln: %u cy: "SIZE_FORMAT,
36 name(), message, length(), total_capacity_bytes());
37 fill_in_ext_msg_extra(msg);
38 }
40 #ifndef PRODUCT
41 void HeapRegionSetBase::verify_region(HeapRegion* hr) {
42 assert(hr->containing_set() == this, err_msg("Inconsistent containing set for %u", hr->hrm_index()));
43 assert(!hr->is_young(), err_msg("Adding young region %u", hr->hrm_index())); // currently we don't use these sets for young regions
44 assert(hr->isHumongous() == regions_humongous(), err_msg("Wrong humongous state for region %u and set %s", hr->hrm_index(), name()));
45 assert(hr->is_free() == regions_free(), err_msg("Wrong free state for region %u and set %s", hr->hrm_index(), name()));
46 assert(!hr->is_free() || hr->is_empty(), err_msg("Free region %u is not empty for set %s", hr->hrm_index(), name()));
47 assert(!hr->is_empty() || hr->is_free(), err_msg("Empty region %u is not free for set %s", hr->hrm_index(), name()));
48 assert(hr->rem_set()->verify_ready_for_par_iteration(), err_msg("Wrong iteration state %u", hr->hrm_index()));
49 }
50 #endif
52 void HeapRegionSetBase::verify() {
53 // It's important that we also observe the MT safety protocol even
54 // for the verification calls. If we do verification without the
55 // appropriate locks and the set changes underneath our feet
56 // verification might fail and send us on a wild goose chase.
57 check_mt_safety();
59 guarantee(( is_empty() && length() == 0 && total_capacity_bytes() == 0) ||
60 (!is_empty() && length() >= 0 && total_capacity_bytes() >= 0),
61 hrs_ext_msg(this, "invariant"));
62 }
64 void HeapRegionSetBase::verify_start() {
65 // See comment in verify() about MT safety and verification.
66 check_mt_safety();
67 assert(!_verify_in_progress,
68 hrs_ext_msg(this, "verification should not be in progress"));
70 // Do the basic verification first before we do the checks over the regions.
71 HeapRegionSetBase::verify();
73 _verify_in_progress = true;
74 }
76 void HeapRegionSetBase::verify_end() {
77 // See comment in verify() about MT safety and verification.
78 check_mt_safety();
79 assert(_verify_in_progress,
80 hrs_ext_msg(this, "verification should be in progress"));
82 _verify_in_progress = false;
83 }
85 void HeapRegionSetBase::print_on(outputStream* out, bool print_contents) {
86 out->cr();
87 out->print_cr("Set: %s ("PTR_FORMAT")", name(), this);
88 out->print_cr(" Region Assumptions");
89 out->print_cr(" humongous : %s", BOOL_TO_STR(regions_humongous()));
90 out->print_cr(" free : %s", BOOL_TO_STR(regions_free()));
91 out->print_cr(" Attributes");
92 out->print_cr(" length : %14u", length());
93 out->print_cr(" total capacity : "SIZE_FORMAT_W(14)" bytes",
94 total_capacity_bytes());
95 }
97 HeapRegionSetBase::HeapRegionSetBase(const char* name, bool humongous, bool free, HRSMtSafeChecker* mt_safety_checker)
98 : _name(name), _verify_in_progress(false),
99 _is_humongous(humongous), _is_free(free), _mt_safety_checker(mt_safety_checker),
100 _count()
101 { }
103 void FreeRegionList::set_unrealistically_long_length(uint len) {
104 guarantee(_unrealistically_long_length == 0, "should only be set once");
105 _unrealistically_long_length = len;
106 }
108 void FreeRegionList::fill_in_ext_msg_extra(hrs_ext_msg* msg) {
109 msg->append(" hd: "PTR_FORMAT" tl: "PTR_FORMAT, _head, _tail);
110 }
112 void FreeRegionList::remove_all() {
113 check_mt_safety();
114 verify_optional();
116 HeapRegion* curr = _head;
117 while (curr != NULL) {
118 verify_region(curr);
120 HeapRegion* next = curr->next();
121 curr->set_next(NULL);
122 curr->set_prev(NULL);
123 curr->set_containing_set(NULL);
124 curr = next;
125 }
126 clear();
128 verify_optional();
129 }
131 void FreeRegionList::add_ordered(FreeRegionList* from_list) {
132 check_mt_safety();
133 from_list->check_mt_safety();
135 verify_optional();
136 from_list->verify_optional();
138 if (from_list->is_empty()) {
139 return;
140 }
142 #ifdef ASSERT
143 FreeRegionListIterator iter(from_list);
144 while (iter.more_available()) {
145 HeapRegion* hr = iter.get_next();
146 // In set_containing_set() we check that we either set the value
147 // from NULL to non-NULL or vice versa to catch bugs. So, we have
148 // to NULL it first before setting it to the value.
149 hr->set_containing_set(NULL);
150 hr->set_containing_set(this);
151 }
152 #endif // ASSERT
154 if (is_empty()) {
155 assert(length() == 0 && _tail == NULL, hrs_ext_msg(this, "invariant"));
156 _head = from_list->_head;
157 _tail = from_list->_tail;
158 } else {
159 HeapRegion* curr_to = _head;
160 HeapRegion* curr_from = from_list->_head;
162 while (curr_from != NULL) {
163 while (curr_to != NULL && curr_to->hrm_index() < curr_from->hrm_index()) {
164 curr_to = curr_to->next();
165 }
167 if (curr_to == NULL) {
168 // The rest of the from list should be added as tail
169 _tail->set_next(curr_from);
170 curr_from->set_prev(_tail);
171 curr_from = NULL;
172 } else {
173 HeapRegion* next_from = curr_from->next();
175 curr_from->set_next(curr_to);
176 curr_from->set_prev(curr_to->prev());
177 if (curr_to->prev() == NULL) {
178 _head = curr_from;
179 } else {
180 curr_to->prev()->set_next(curr_from);
181 }
182 curr_to->set_prev(curr_from);
184 curr_from = next_from;
185 }
186 }
188 if (_tail->hrm_index() < from_list->_tail->hrm_index()) {
189 _tail = from_list->_tail;
190 }
191 }
193 _count.increment(from_list->length(), from_list->total_capacity_bytes());
194 from_list->clear();
196 verify_optional();
197 from_list->verify_optional();
198 }
200 void FreeRegionList::remove_starting_at(HeapRegion* first, uint num_regions) {
201 check_mt_safety();
202 assert(num_regions >= 1, hrs_ext_msg(this, "pre-condition"));
203 assert(!is_empty(), hrs_ext_msg(this, "pre-condition"));
205 verify_optional();
206 DEBUG_ONLY(uint old_length = length();)
208 HeapRegion* curr = first;
209 uint count = 0;
210 while (count < num_regions) {
211 verify_region(curr);
212 HeapRegion* next = curr->next();
213 HeapRegion* prev = curr->prev();
215 assert(count < num_regions,
216 hrs_err_msg("[%s] should not come across more regions "
217 "pending for removal than num_regions: %u",
218 name(), num_regions));
220 if (prev == NULL) {
221 assert(_head == curr, hrs_ext_msg(this, "invariant"));
222 _head = next;
223 } else {
224 assert(_head != curr, hrs_ext_msg(this, "invariant"));
225 prev->set_next(next);
226 }
227 if (next == NULL) {
228 assert(_tail == curr, hrs_ext_msg(this, "invariant"));
229 _tail = prev;
230 } else {
231 assert(_tail != curr, hrs_ext_msg(this, "invariant"));
232 next->set_prev(prev);
233 }
234 if (_last = curr) {
235 _last = NULL;
236 }
238 curr->set_next(NULL);
239 curr->set_prev(NULL);
240 remove(curr);
242 count++;
243 curr = next;
244 }
246 assert(count == num_regions,
247 hrs_err_msg("[%s] count: %u should be == num_regions: %u",
248 name(), count, num_regions));
249 assert(length() + num_regions == old_length,
250 hrs_err_msg("[%s] new length should be consistent "
251 "new length: %u old length: %u num_regions: %u",
252 name(), length(), old_length, num_regions));
254 verify_optional();
255 }
257 void FreeRegionList::verify() {
258 // See comment in HeapRegionSetBase::verify() about MT safety and
259 // verification.
260 check_mt_safety();
262 // This will also do the basic verification too.
263 verify_start();
265 verify_list();
267 verify_end();
268 }
270 void FreeRegionList::clear() {
271 _count = HeapRegionSetCount();
272 _head = NULL;
273 _tail = NULL;
274 _last = NULL;
275 }
277 void FreeRegionList::print_on(outputStream* out, bool print_contents) {
278 HeapRegionSetBase::print_on(out, print_contents);
279 out->print_cr(" Linking");
280 out->print_cr(" head : "PTR_FORMAT, _head);
281 out->print_cr(" tail : "PTR_FORMAT, _tail);
283 if (print_contents) {
284 out->print_cr(" Contents");
285 FreeRegionListIterator iter(this);
286 while (iter.more_available()) {
287 HeapRegion* hr = iter.get_next();
288 hr->print_on(out);
289 }
290 }
292 out->cr();
293 }
295 void FreeRegionList::verify_list() {
296 HeapRegion* curr = _head;
297 HeapRegion* prev1 = NULL;
298 HeapRegion* prev0 = NULL;
299 uint count = 0;
300 size_t capacity = 0;
301 uint last_index = 0;
303 guarantee(_head == NULL || _head->prev() == NULL, "_head should not have a prev");
304 while (curr != NULL) {
305 verify_region(curr);
307 count++;
308 guarantee(count < _unrealistically_long_length,
309 hrs_err_msg("[%s] the calculated length: %u seems very long, is there maybe a cycle? curr: "PTR_FORMAT" prev0: "PTR_FORMAT" " "prev1: "PTR_FORMAT" length: %u", name(), count, curr, prev0, prev1, length()));
311 if (curr->next() != NULL) {
312 guarantee(curr->next()->prev() == curr, "Next or prev pointers messed up");
313 }
314 guarantee(curr->hrm_index() == 0 || curr->hrm_index() > last_index, "List should be sorted");
315 last_index = curr->hrm_index();
317 capacity += curr->capacity();
319 prev1 = prev0;
320 prev0 = curr;
321 curr = curr->next();
322 }
324 guarantee(_tail == prev0, err_msg("Expected %s to end with %u but it ended with %u.", name(), _tail->hrm_index(), prev0->hrm_index()));
325 guarantee(_tail == NULL || _tail->next() == NULL, "_tail should not have a next");
326 guarantee(length() == count, err_msg("%s count mismatch. Expected %u, actual %u.", name(), length(), count));
327 guarantee(total_capacity_bytes() == capacity, err_msg("%s capacity mismatch. Expected " SIZE_FORMAT ", actual " SIZE_FORMAT,
328 name(), total_capacity_bytes(), capacity));
329 }
331 // Note on the check_mt_safety() methods below:
332 //
333 // Verification of the "master" heap region sets / lists that are
334 // maintained by G1CollectedHeap is always done during a STW pause and
335 // by the VM thread at the start / end of the pause. The standard
336 // verification methods all assert check_mt_safety(). This is
337 // important as it ensures that verification is done without
338 // concurrent updates taking place at the same time. It follows, that,
339 // for the "master" heap region sets / lists, the check_mt_safety()
340 // method should include the VM thread / STW case.
342 void MasterFreeRegionListMtSafeChecker::check() {
343 // Master Free List MT safety protocol:
344 // (a) If we're at a safepoint, operations on the master free list
345 // should be invoked by either the VM thread (which will serialize
346 // them) or by the GC workers while holding the
347 // FreeList_lock.
348 // (b) If we're not at a safepoint, operations on the master free
349 // list should be invoked while holding the Heap_lock.
351 if (SafepointSynchronize::is_at_safepoint()) {
352 guarantee(Thread::current()->is_VM_thread() ||
353 FreeList_lock->owned_by_self(), "master free list MT safety protocol at a safepoint");
354 } else {
355 guarantee(Heap_lock->owned_by_self(), "master free list MT safety protocol outside a safepoint");
356 }
357 }
359 void SecondaryFreeRegionListMtSafeChecker::check() {
360 // Secondary Free List MT safety protocol:
361 // Operations on the secondary free list should always be invoked
362 // while holding the SecondaryFreeList_lock.
364 guarantee(SecondaryFreeList_lock->owned_by_self(), "secondary free list MT safety protocol");
365 }
367 void OldRegionSetMtSafeChecker::check() {
368 // Master Old Set MT safety protocol:
369 // (a) If we're at a safepoint, operations on the master old set
370 // should be invoked:
371 // - by the VM thread (which will serialize them), or
372 // - by the GC workers while holding the FreeList_lock, if we're
373 // at a safepoint for an evacuation pause (this lock is taken
374 // anyway when an GC alloc region is retired so that a new one
375 // is allocated from the free list), or
376 // - by the GC workers while holding the OldSets_lock, if we're at a
377 // safepoint for a cleanup pause.
378 // (b) If we're not at a safepoint, operations on the master old set
379 // should be invoked while holding the Heap_lock.
381 if (SafepointSynchronize::is_at_safepoint()) {
382 guarantee(Thread::current()->is_VM_thread()
383 || FreeList_lock->owned_by_self() || OldSets_lock->owned_by_self(),
384 "master old set MT safety protocol at a safepoint");
385 } else {
386 guarantee(Heap_lock->owned_by_self(), "master old set MT safety protocol outside a safepoint");
387 }
388 }
390 void HumongousRegionSetMtSafeChecker::check() {
391 // Humongous Set MT safety protocol:
392 // (a) If we're at a safepoint, operations on the master humongous
393 // set should be invoked by either the VM thread (which will
394 // serialize them) or by the GC workers while holding the
395 // OldSets_lock.
396 // (b) If we're not at a safepoint, operations on the master
397 // humongous set should be invoked while holding the Heap_lock.
399 if (SafepointSynchronize::is_at_safepoint()) {
400 guarantee(Thread::current()->is_VM_thread() ||
401 OldSets_lock->owned_by_self(),
402 "master humongous set MT safety protocol at a safepoint");
403 } else {
404 guarantee(Heap_lock->owned_by_self(),
405 "master humongous set MT safety protocol outside a safepoint");
406 }
407 }
409 void FreeRegionList_test() {
410 FreeRegionList l("test");
412 const uint num_regions_in_test = 5;
413 // Create a fake heap. It does not need to be valid, as the HeapRegion constructor
414 // does not access it.
415 MemRegion heap(NULL, num_regions_in_test * HeapRegion::GrainWords);
416 // Allocate a fake BOT because the HeapRegion constructor initializes
417 // the BOT.
418 size_t bot_size = G1BlockOffsetSharedArray::compute_size(heap.word_size());
419 HeapWord* bot_data = NEW_C_HEAP_ARRAY(HeapWord, bot_size, mtGC);
420 ReservedSpace bot_rs(G1BlockOffsetSharedArray::compute_size(heap.word_size()));
421 G1RegionToSpaceMapper* bot_storage =
422 G1RegionToSpaceMapper::create_mapper(bot_rs,
423 bot_rs.size(),
424 os::vm_page_size(),
425 HeapRegion::GrainBytes,
426 G1BlockOffsetSharedArray::N_bytes,
427 mtGC);
428 G1BlockOffsetSharedArray oa(heap, bot_storage);
429 bot_storage->commit_regions(0, num_regions_in_test);
430 HeapRegion hr0(0, &oa, heap);
431 HeapRegion hr1(1, &oa, heap);
432 HeapRegion hr2(2, &oa, heap);
433 HeapRegion hr3(3, &oa, heap);
434 HeapRegion hr4(4, &oa, heap);
435 l.add_ordered(&hr1);
436 l.add_ordered(&hr0);
437 l.add_ordered(&hr3);
438 l.add_ordered(&hr4);
439 l.add_ordered(&hr2);
440 assert(l.length() == num_regions_in_test, "wrong length");
441 l.verify_list();
443 bot_storage->uncommit_regions(0, num_regions_in_test);
444 delete bot_storage;
445 FREE_C_HEAP_ARRAY(HeapWord, bot_data, mtGC);
446 }