Mon, 17 Mar 2014 13:42:16 +0100
8037407: G1: Remove heapRegionSets.cpp
Reviewed-by: tschatzl, pliden
1 /*
2 * Copyright (c) 2011, 2012, 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
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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/heapRegionRemSet.hpp"
27 #include "gc_implementation/g1/heapRegionSet.inline.hpp"
29 uint FreeRegionList::_unrealistically_long_length = 0;
31 void HeapRegionSetBase::fill_in_ext_msg(hrs_ext_msg* msg, const char* message) {
32 msg->append("[%s] %s ln: %u cy: "SIZE_FORMAT,
33 name(), message, length(), total_capacity_bytes());
34 fill_in_ext_msg_extra(msg);
35 }
37 #ifndef PRODUCT
38 void HeapRegionSetBase::verify_region(HeapRegion* hr) {
39 assert(hr->containing_set() == this, err_msg("Inconsistent containing set for %u", hr->hrs_index()));
40 assert(!hr->is_young(), err_msg("Adding young region %u", hr->hrs_index())); // currently we don't use these sets for young regions
41 assert(hr->isHumongous() == regions_humongous(), err_msg("Wrong humongous state for region %u and set %s", hr->hrs_index(), name()));
42 assert(hr->is_empty() == regions_empty(), err_msg("Wrong empty state for region %u and set %s", hr->hrs_index(), name()));
43 assert(hr->rem_set()->verify_ready_for_par_iteration(), err_msg("Wrong iteration state %u", hr->hrs_index()));
44 }
45 #endif
47 void HeapRegionSetBase::verify() {
48 // It's important that we also observe the MT safety protocol even
49 // for the verification calls. If we do verification without the
50 // appropriate locks and the set changes underneath our feet
51 // verification might fail and send us on a wild goose chase.
52 check_mt_safety();
54 guarantee(( is_empty() && length() == 0 && total_capacity_bytes() == 0) ||
55 (!is_empty() && length() >= 0 && total_capacity_bytes() >= 0),
56 hrs_ext_msg(this, "invariant"));
57 }
59 void HeapRegionSetBase::verify_start() {
60 // See comment in verify() about MT safety and verification.
61 check_mt_safety();
62 assert(!_verify_in_progress,
63 hrs_ext_msg(this, "verification should not be in progress"));
65 // Do the basic verification first before we do the checks over the regions.
66 HeapRegionSetBase::verify();
68 _verify_in_progress = true;
69 }
71 void HeapRegionSetBase::verify_end() {
72 // See comment in verify() about MT safety and verification.
73 check_mt_safety();
74 assert(_verify_in_progress,
75 hrs_ext_msg(this, "verification should be in progress"));
77 _verify_in_progress = false;
78 }
80 void HeapRegionSetBase::print_on(outputStream* out, bool print_contents) {
81 out->cr();
82 out->print_cr("Set: %s ("PTR_FORMAT")", name(), this);
83 out->print_cr(" Region Assumptions");
84 out->print_cr(" humongous : %s", BOOL_TO_STR(regions_humongous()));
85 out->print_cr(" empty : %s", BOOL_TO_STR(regions_empty()));
86 out->print_cr(" Attributes");
87 out->print_cr(" length : %14u", length());
88 out->print_cr(" total capacity : "SIZE_FORMAT_W(14)" bytes",
89 total_capacity_bytes());
90 }
92 HeapRegionSetBase::HeapRegionSetBase(const char* name, bool humongous, bool empty, HRSMtSafeChecker* mt_safety_checker)
93 : _name(name), _verify_in_progress(false),
94 _is_humongous(humongous), _is_empty(empty), _mt_safety_checker(mt_safety_checker),
95 _count()
96 { }
98 void FreeRegionList::set_unrealistically_long_length(uint len) {
99 guarantee(_unrealistically_long_length == 0, "should only be set once");
100 _unrealistically_long_length = len;
101 }
103 void FreeRegionList::fill_in_ext_msg_extra(hrs_ext_msg* msg) {
104 msg->append(" hd: "PTR_FORMAT" tl: "PTR_FORMAT, head(), tail());
105 }
107 void FreeRegionList::add_as_head_or_tail(FreeRegionList* from_list, bool as_head) {
108 check_mt_safety();
109 from_list->check_mt_safety();
111 verify_optional();
112 from_list->verify_optional();
114 if (from_list->is_empty()) {
115 return;
116 }
118 #ifdef ASSERT
119 FreeRegionListIterator iter(from_list);
120 while (iter.more_available()) {
121 HeapRegion* hr = iter.get_next();
122 // In set_containing_set() we check that we either set the value
123 // from NULL to non-NULL or vice versa to catch bugs. So, we have
124 // to NULL it first before setting it to the value.
125 hr->set_containing_set(NULL);
126 hr->set_containing_set(this);
127 }
128 #endif // ASSERT
130 if (_head == NULL) {
131 assert(length() == 0 && _tail == NULL, hrs_ext_msg(this, "invariant"));
132 _head = from_list->_head;
133 _tail = from_list->_tail;
134 } else {
135 assert(length() > 0 && _tail != NULL, hrs_ext_msg(this, "invariant"));
136 if (as_head) {
137 from_list->_tail->set_next(_head);
138 _head = from_list->_head;
139 } else {
140 _tail->set_next(from_list->_head);
141 _tail = from_list->_tail;
142 }
143 }
145 _count.increment(from_list->length(), from_list->total_capacity_bytes());
146 from_list->clear();
148 verify_optional();
149 from_list->verify_optional();
150 }
152 void FreeRegionList::add_as_head(FreeRegionList* from_list) {
153 add_as_head_or_tail(from_list, true /* as_head */);
154 }
156 void FreeRegionList::add_as_tail(FreeRegionList* from_list) {
157 add_as_head_or_tail(from_list, false /* as_head */);
158 }
160 void FreeRegionList::remove_all() {
161 check_mt_safety();
162 verify_optional();
164 HeapRegion* curr = _head;
165 while (curr != NULL) {
166 verify_region(curr);
168 HeapRegion* next = curr->next();
169 curr->set_next(NULL);
170 curr->set_containing_set(NULL);
171 curr = next;
172 }
173 clear();
175 verify_optional();
176 }
178 void FreeRegionList::remove_all_pending(uint target_count) {
179 check_mt_safety();
180 assert(target_count > 1, hrs_ext_msg(this, "pre-condition"));
181 assert(!is_empty(), hrs_ext_msg(this, "pre-condition"));
183 verify_optional();
184 DEBUG_ONLY(uint old_length = length();)
186 HeapRegion* curr = _head;
187 HeapRegion* prev = NULL;
188 uint count = 0;
189 while (curr != NULL) {
190 verify_region(curr);
191 HeapRegion* next = curr->next();
193 if (curr->pending_removal()) {
194 assert(count < target_count,
195 hrs_err_msg("[%s] should not come across more regions "
196 "pending for removal than target_count: %u",
197 name(), target_count));
199 if (prev == NULL) {
200 assert(_head == curr, hrs_ext_msg(this, "invariant"));
201 _head = next;
202 } else {
203 assert(_head != curr, hrs_ext_msg(this, "invariant"));
204 prev->set_next(next);
205 }
206 if (next == NULL) {
207 assert(_tail == curr, hrs_ext_msg(this, "invariant"));
208 _tail = prev;
209 } else {
210 assert(_tail != curr, hrs_ext_msg(this, "invariant"));
211 }
213 curr->set_next(NULL);
214 remove(curr);
215 curr->set_pending_removal(false);
217 count += 1;
219 // If we have come across the target number of regions we can
220 // just bail out. However, for debugging purposes, we can just
221 // carry on iterating to make sure there are not more regions
222 // tagged with pending removal.
223 DEBUG_ONLY(if (count == target_count) break;)
224 } else {
225 prev = curr;
226 }
227 curr = next;
228 }
230 assert(count == target_count,
231 hrs_err_msg("[%s] count: %u should be == target_count: %u",
232 name(), count, target_count));
233 assert(length() + target_count == old_length,
234 hrs_err_msg("[%s] new length should be consistent "
235 "new length: %u old length: %u target_count: %u",
236 name(), length(), old_length, target_count));
238 verify_optional();
239 }
241 void FreeRegionList::verify() {
242 // See comment in HeapRegionSetBase::verify() about MT safety and
243 // verification.
244 check_mt_safety();
246 // This will also do the basic verification too.
247 verify_start();
249 verify_list();
251 verify_end();
252 }
254 void FreeRegionList::clear() {
255 _count = HeapRegionSetCount();
256 _head = NULL;
257 _tail = NULL;
258 }
260 void FreeRegionList::print_on(outputStream* out, bool print_contents) {
261 HeapRegionSetBase::print_on(out, print_contents);
262 out->print_cr(" Linking");
263 out->print_cr(" head : "PTR_FORMAT, _head);
264 out->print_cr(" tail : "PTR_FORMAT, _tail);
266 if (print_contents) {
267 out->print_cr(" Contents");
268 FreeRegionListIterator iter(this);
269 while (iter.more_available()) {
270 HeapRegion* hr = iter.get_next();
271 hr->print_on(out);
272 }
273 }
274 }
276 void FreeRegionList::verify_list() {
277 HeapRegion* curr = head();
278 HeapRegion* prev1 = NULL;
279 HeapRegion* prev0 = NULL;
280 uint count = 0;
281 size_t capacity = 0;
282 while (curr != NULL) {
283 verify_region(curr);
285 count++;
286 guarantee(count < _unrealistically_long_length,
287 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()));
289 capacity += curr->capacity();
291 prev1 = prev0;
292 prev0 = curr;
293 curr = curr->next();
294 }
296 guarantee(tail() == prev0, err_msg("Expected %s to end with %u but it ended with %u.", name(), tail()->hrs_index(), prev0->hrs_index()));
298 guarantee(length() == count, err_msg("%s count mismatch. Expected %u, actual %u.", name(), length(), count));
299 guarantee(total_capacity_bytes() == capacity, err_msg("%s capacity mismatch. Expected " SIZE_FORMAT ", actual " SIZE_FORMAT,
300 name(), total_capacity_bytes(), capacity));
301 }
303 // Note on the check_mt_safety() methods below:
304 //
305 // Verification of the "master" heap region sets / lists that are
306 // maintained by G1CollectedHeap is always done during a STW pause and
307 // by the VM thread at the start / end of the pause. The standard
308 // verification methods all assert check_mt_safety(). This is
309 // important as it ensures that verification is done without
310 // concurrent updates taking place at the same time. It follows, that,
311 // for the "master" heap region sets / lists, the check_mt_safety()
312 // method should include the VM thread / STW case.
314 void MasterFreeRegionListMtSafeChecker::check() {
315 // Master Free List MT safety protocol:
316 // (a) If we're at a safepoint, operations on the master free list
317 // should be invoked by either the VM thread (which will serialize
318 // them) or by the GC workers while holding the
319 // FreeList_lock.
320 // (b) If we're not at a safepoint, operations on the master free
321 // list should be invoked while holding the Heap_lock.
323 if (SafepointSynchronize::is_at_safepoint()) {
324 guarantee(Thread::current()->is_VM_thread() ||
325 FreeList_lock->owned_by_self(), "master free list MT safety protocol at a safepoint");
326 } else {
327 guarantee(Heap_lock->owned_by_self(), "master free list MT safety protocol outside a safepoint");
328 }
329 }
331 void SecondaryFreeRegionListMtSafeChecker::check() {
332 // Secondary Free List MT safety protocol:
333 // Operations on the secondary free list should always be invoked
334 // while holding the SecondaryFreeList_lock.
336 guarantee(SecondaryFreeList_lock->owned_by_self(), "secondary free list MT safety protocol");
337 }
339 void OldRegionSetMtSafeChecker::check() {
340 // Master Old Set MT safety protocol:
341 // (a) If we're at a safepoint, operations on the master old set
342 // should be invoked:
343 // - by the VM thread (which will serialize them), or
344 // - by the GC workers while holding the FreeList_lock, if we're
345 // at a safepoint for an evacuation pause (this lock is taken
346 // anyway when an GC alloc region is retired so that a new one
347 // is allocated from the free list), or
348 // - by the GC workers while holding the OldSets_lock, if we're at a
349 // safepoint for a cleanup pause.
350 // (b) If we're not at a safepoint, operations on the master old set
351 // should be invoked while holding the Heap_lock.
353 if (SafepointSynchronize::is_at_safepoint()) {
354 guarantee(Thread::current()->is_VM_thread()
355 || FreeList_lock->owned_by_self() || OldSets_lock->owned_by_self(),
356 "master old set MT safety protocol at a safepoint");
357 } else {
358 guarantee(Heap_lock->owned_by_self(), "master old set MT safety protocol outside a safepoint");
359 }
360 }
362 void HumongousRegionSetMtSafeChecker::check() {
363 // Humongous Set MT safety protocol:
364 // (a) If we're at a safepoint, operations on the master humongous
365 // set should be invoked by either the VM thread (which will
366 // serialize them) or by the GC workers while holding the
367 // OldSets_lock.
368 // (b) If we're not at a safepoint, operations on the master
369 // humongous set should be invoked while holding the Heap_lock.
371 if (SafepointSynchronize::is_at_safepoint()) {
372 guarantee(Thread::current()->is_VM_thread() ||
373 OldSets_lock->owned_by_self(),
374 "master humongous set MT safety protocol at a safepoint");
375 } else {
376 guarantee(Heap_lock->owned_by_self(),
377 "master humongous set MT safety protocol outside a safepoint");
378 }
379 }