1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/gc_implementation/g1/heapRegionSet.cpp Wed Apr 27 01:25:04 2016 +0800
1.3 @@ -0,0 +1,465 @@
1.4 +/*
1.5 + * Copyright (c) 2011, 2014, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + *
1.26 + */
1.27 +
1.28 +#include "precompiled.hpp"
1.29 +#include "gc_implementation/g1/heapRegionRemSet.hpp"
1.30 +#include "gc_implementation/g1/heapRegionSet.inline.hpp"
1.31 +
1.32 +PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
1.33 +
1.34 +uint FreeRegionList::_unrealistically_long_length = 0;
1.35 +
1.36 +void HeapRegionSetBase::fill_in_ext_msg(hrs_ext_msg* msg, const char* message) {
1.37 + msg->append("[%s] %s ln: %u cy: "SIZE_FORMAT,
1.38 + name(), message, length(), total_capacity_bytes());
1.39 + fill_in_ext_msg_extra(msg);
1.40 +}
1.41 +
1.42 +#ifndef PRODUCT
1.43 +void HeapRegionSetBase::verify_region(HeapRegion* hr) {
1.44 + assert(hr->containing_set() == this, err_msg("Inconsistent containing set for %u", hr->hrs_index()));
1.45 + assert(!hr->is_young(), err_msg("Adding young region %u", hr->hrs_index())); // currently we don't use these sets for young regions
1.46 + assert(hr->isHumongous() == regions_humongous(), err_msg("Wrong humongous state for region %u and set %s", hr->hrs_index(), name()));
1.47 + assert(hr->is_empty() == regions_empty(), err_msg("Wrong empty state for region %u and set %s", hr->hrs_index(), name()));
1.48 + assert(hr->rem_set()->verify_ready_for_par_iteration(), err_msg("Wrong iteration state %u", hr->hrs_index()));
1.49 +}
1.50 +#endif
1.51 +
1.52 +void HeapRegionSetBase::verify() {
1.53 + // It's important that we also observe the MT safety protocol even
1.54 + // for the verification calls. If we do verification without the
1.55 + // appropriate locks and the set changes underneath our feet
1.56 + // verification might fail and send us on a wild goose chase.
1.57 + check_mt_safety();
1.58 +
1.59 + guarantee(( is_empty() && length() == 0 && total_capacity_bytes() == 0) ||
1.60 + (!is_empty() && length() >= 0 && total_capacity_bytes() >= 0),
1.61 + hrs_ext_msg(this, "invariant"));
1.62 +}
1.63 +
1.64 +void HeapRegionSetBase::verify_start() {
1.65 + // See comment in verify() about MT safety and verification.
1.66 + check_mt_safety();
1.67 + assert(!_verify_in_progress,
1.68 + hrs_ext_msg(this, "verification should not be in progress"));
1.69 +
1.70 + // Do the basic verification first before we do the checks over the regions.
1.71 + HeapRegionSetBase::verify();
1.72 +
1.73 + _verify_in_progress = true;
1.74 +}
1.75 +
1.76 +void HeapRegionSetBase::verify_end() {
1.77 + // See comment in verify() about MT safety and verification.
1.78 + check_mt_safety();
1.79 + assert(_verify_in_progress,
1.80 + hrs_ext_msg(this, "verification should be in progress"));
1.81 +
1.82 + _verify_in_progress = false;
1.83 +}
1.84 +
1.85 +void HeapRegionSetBase::print_on(outputStream* out, bool print_contents) {
1.86 + out->cr();
1.87 + out->print_cr("Set: %s ("PTR_FORMAT")", name(), this);
1.88 + out->print_cr(" Region Assumptions");
1.89 + out->print_cr(" humongous : %s", BOOL_TO_STR(regions_humongous()));
1.90 + out->print_cr(" empty : %s", BOOL_TO_STR(regions_empty()));
1.91 + out->print_cr(" Attributes");
1.92 + out->print_cr(" length : %14u", length());
1.93 + out->print_cr(" total capacity : "SIZE_FORMAT_W(14)" bytes",
1.94 + total_capacity_bytes());
1.95 +}
1.96 +
1.97 +HeapRegionSetBase::HeapRegionSetBase(const char* name, bool humongous, bool empty, HRSMtSafeChecker* mt_safety_checker)
1.98 + : _name(name), _verify_in_progress(false),
1.99 + _is_humongous(humongous), _is_empty(empty), _mt_safety_checker(mt_safety_checker),
1.100 + _count()
1.101 +{ }
1.102 +
1.103 +void FreeRegionList::set_unrealistically_long_length(uint len) {
1.104 + guarantee(_unrealistically_long_length == 0, "should only be set once");
1.105 + _unrealistically_long_length = len;
1.106 +}
1.107 +
1.108 +void FreeRegionList::fill_in_ext_msg_extra(hrs_ext_msg* msg) {
1.109 + msg->append(" hd: "PTR_FORMAT" tl: "PTR_FORMAT, head(), tail());
1.110 +}
1.111 +
1.112 +void FreeRegionList::add_as_head_or_tail(FreeRegionList* from_list, bool as_head) {
1.113 + check_mt_safety();
1.114 + from_list->check_mt_safety();
1.115 +
1.116 + verify_optional();
1.117 + from_list->verify_optional();
1.118 +
1.119 + if (from_list->is_empty()) {
1.120 + return;
1.121 + }
1.122 +
1.123 +#ifdef ASSERT
1.124 + FreeRegionListIterator iter(from_list);
1.125 + while (iter.more_available()) {
1.126 + HeapRegion* hr = iter.get_next();
1.127 + // In set_containing_set() we check that we either set the value
1.128 + // from NULL to non-NULL or vice versa to catch bugs. So, we have
1.129 + // to NULL it first before setting it to the value.
1.130 + hr->set_containing_set(NULL);
1.131 + hr->set_containing_set(this);
1.132 + }
1.133 +#endif // ASSERT
1.134 +
1.135 + if (_head == NULL) {
1.136 + assert(length() == 0 && _tail == NULL, hrs_ext_msg(this, "invariant"));
1.137 + _head = from_list->_head;
1.138 + _tail = from_list->_tail;
1.139 + } else {
1.140 + assert(length() > 0 && _tail != NULL, hrs_ext_msg(this, "invariant"));
1.141 + if (as_head) {
1.142 + from_list->_tail->set_next(_head);
1.143 + _head->set_prev(from_list->_tail);
1.144 + _head = from_list->_head;
1.145 + } else {
1.146 + _tail->set_next(from_list->_head);
1.147 + from_list->_head->set_prev(_tail);
1.148 + _tail = from_list->_tail;
1.149 + }
1.150 + }
1.151 +
1.152 + _count.increment(from_list->length(), from_list->total_capacity_bytes());
1.153 + from_list->clear();
1.154 +
1.155 + verify_optional();
1.156 + from_list->verify_optional();
1.157 +}
1.158 +
1.159 +void FreeRegionList::add_as_head(FreeRegionList* from_list) {
1.160 + add_as_head_or_tail(from_list, true /* as_head */);
1.161 +}
1.162 +
1.163 +void FreeRegionList::add_as_tail(FreeRegionList* from_list) {
1.164 + add_as_head_or_tail(from_list, false /* as_head */);
1.165 +}
1.166 +
1.167 +void FreeRegionList::remove_all() {
1.168 + check_mt_safety();
1.169 + verify_optional();
1.170 +
1.171 + HeapRegion* curr = _head;
1.172 + while (curr != NULL) {
1.173 + verify_region(curr);
1.174 +
1.175 + HeapRegion* next = curr->next();
1.176 + curr->set_next(NULL);
1.177 + curr->set_prev(NULL);
1.178 + curr->set_containing_set(NULL);
1.179 + curr = next;
1.180 + }
1.181 + clear();
1.182 +
1.183 + verify_optional();
1.184 +}
1.185 +
1.186 +void FreeRegionList::add_ordered(FreeRegionList* from_list) {
1.187 + check_mt_safety();
1.188 + from_list->check_mt_safety();
1.189 +
1.190 + verify_optional();
1.191 + from_list->verify_optional();
1.192 +
1.193 + if (from_list->is_empty()) {
1.194 + return;
1.195 + }
1.196 +
1.197 + if (is_empty()) {
1.198 + add_as_head(from_list);
1.199 + return;
1.200 + }
1.201 +
1.202 + #ifdef ASSERT
1.203 + FreeRegionListIterator iter(from_list);
1.204 + while (iter.more_available()) {
1.205 + HeapRegion* hr = iter.get_next();
1.206 + // In set_containing_set() we check that we either set the value
1.207 + // from NULL to non-NULL or vice versa to catch bugs. So, we have
1.208 + // to NULL it first before setting it to the value.
1.209 + hr->set_containing_set(NULL);
1.210 + hr->set_containing_set(this);
1.211 + }
1.212 + #endif // ASSERT
1.213 +
1.214 + HeapRegion* curr_to = _head;
1.215 + HeapRegion* curr_from = from_list->_head;
1.216 +
1.217 + while (curr_from != NULL) {
1.218 + while (curr_to != NULL && curr_to->hrs_index() < curr_from->hrs_index()) {
1.219 + curr_to = curr_to->next();
1.220 + }
1.221 +
1.222 + if (curr_to == NULL) {
1.223 + // The rest of the from list should be added as tail
1.224 + _tail->set_next(curr_from);
1.225 + curr_from->set_prev(_tail);
1.226 + curr_from = NULL;
1.227 + } else {
1.228 + HeapRegion* next_from = curr_from->next();
1.229 +
1.230 + curr_from->set_next(curr_to);
1.231 + curr_from->set_prev(curr_to->prev());
1.232 + if (curr_to->prev() == NULL) {
1.233 + _head = curr_from;
1.234 + } else {
1.235 + curr_to->prev()->set_next(curr_from);
1.236 + }
1.237 + curr_to->set_prev(curr_from);
1.238 +
1.239 + curr_from = next_from;
1.240 + }
1.241 + }
1.242 +
1.243 + if (_tail->hrs_index() < from_list->_tail->hrs_index()) {
1.244 + _tail = from_list->_tail;
1.245 + }
1.246 +
1.247 + _count.increment(from_list->length(), from_list->total_capacity_bytes());
1.248 + from_list->clear();
1.249 +
1.250 + verify_optional();
1.251 + from_list->verify_optional();
1.252 +}
1.253 +
1.254 +void FreeRegionList::remove_all_pending(uint target_count) {
1.255 + check_mt_safety();
1.256 + assert(target_count > 1, hrs_ext_msg(this, "pre-condition"));
1.257 + assert(!is_empty(), hrs_ext_msg(this, "pre-condition"));
1.258 +
1.259 + verify_optional();
1.260 + DEBUG_ONLY(uint old_length = length();)
1.261 +
1.262 + HeapRegion* curr = _head;
1.263 + uint count = 0;
1.264 + while (curr != NULL) {
1.265 + verify_region(curr);
1.266 + HeapRegion* next = curr->next();
1.267 + HeapRegion* prev = curr->prev();
1.268 +
1.269 + if (curr->pending_removal()) {
1.270 + assert(count < target_count,
1.271 + hrs_err_msg("[%s] should not come across more regions "
1.272 + "pending for removal than target_count: %u",
1.273 + name(), target_count));
1.274 +
1.275 + if (prev == NULL) {
1.276 + assert(_head == curr, hrs_ext_msg(this, "invariant"));
1.277 + _head = next;
1.278 + } else {
1.279 + assert(_head != curr, hrs_ext_msg(this, "invariant"));
1.280 + prev->set_next(next);
1.281 + }
1.282 + if (next == NULL) {
1.283 + assert(_tail == curr, hrs_ext_msg(this, "invariant"));
1.284 + _tail = prev;
1.285 + } else {
1.286 + assert(_tail != curr, hrs_ext_msg(this, "invariant"));
1.287 + next->set_prev(prev);
1.288 + }
1.289 + if (_last = curr) {
1.290 + _last = NULL;
1.291 + }
1.292 +
1.293 + curr->set_next(NULL);
1.294 + curr->set_prev(NULL);
1.295 + remove(curr);
1.296 + curr->set_pending_removal(false);
1.297 +
1.298 + count += 1;
1.299 +
1.300 + // If we have come across the target number of regions we can
1.301 + // just bail out. However, for debugging purposes, we can just
1.302 + // carry on iterating to make sure there are not more regions
1.303 + // tagged with pending removal.
1.304 + DEBUG_ONLY(if (count == target_count) break;)
1.305 + }
1.306 + curr = next;
1.307 + }
1.308 +
1.309 + assert(count == target_count,
1.310 + hrs_err_msg("[%s] count: %u should be == target_count: %u",
1.311 + name(), count, target_count));
1.312 + assert(length() + target_count == old_length,
1.313 + hrs_err_msg("[%s] new length should be consistent "
1.314 + "new length: %u old length: %u target_count: %u",
1.315 + name(), length(), old_length, target_count));
1.316 +
1.317 + verify_optional();
1.318 +}
1.319 +
1.320 +void FreeRegionList::verify() {
1.321 + // See comment in HeapRegionSetBase::verify() about MT safety and
1.322 + // verification.
1.323 + check_mt_safety();
1.324 +
1.325 + // This will also do the basic verification too.
1.326 + verify_start();
1.327 +
1.328 + verify_list();
1.329 +
1.330 + verify_end();
1.331 +}
1.332 +
1.333 +void FreeRegionList::clear() {
1.334 + _count = HeapRegionSetCount();
1.335 + _head = NULL;
1.336 + _tail = NULL;
1.337 + _last = NULL;
1.338 +}
1.339 +
1.340 +void FreeRegionList::print_on(outputStream* out, bool print_contents) {
1.341 + HeapRegionSetBase::print_on(out, print_contents);
1.342 + out->print_cr(" Linking");
1.343 + out->print_cr(" head : "PTR_FORMAT, _head);
1.344 + out->print_cr(" tail : "PTR_FORMAT, _tail);
1.345 +
1.346 + if (print_contents) {
1.347 + out->print_cr(" Contents");
1.348 + FreeRegionListIterator iter(this);
1.349 + while (iter.more_available()) {
1.350 + HeapRegion* hr = iter.get_next();
1.351 + hr->print_on(out);
1.352 + }
1.353 + }
1.354 +}
1.355 +
1.356 +void FreeRegionList::verify_list() {
1.357 + HeapRegion* curr = head();
1.358 + HeapRegion* prev1 = NULL;
1.359 + HeapRegion* prev0 = NULL;
1.360 + uint count = 0;
1.361 + size_t capacity = 0;
1.362 + uint last_index = 0;
1.363 +
1.364 + guarantee(_head == NULL || _head->prev() == NULL, "_head should not have a prev");
1.365 + while (curr != NULL) {
1.366 + verify_region(curr);
1.367 +
1.368 + count++;
1.369 + guarantee(count < _unrealistically_long_length,
1.370 + 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()));
1.371 +
1.372 + if (curr->next() != NULL) {
1.373 + guarantee(curr->next()->prev() == curr, "Next or prev pointers messed up");
1.374 + }
1.375 + guarantee(curr->hrs_index() == 0 || curr->hrs_index() > last_index, "List should be sorted");
1.376 + last_index = curr->hrs_index();
1.377 +
1.378 + capacity += curr->capacity();
1.379 +
1.380 + prev1 = prev0;
1.381 + prev0 = curr;
1.382 + curr = curr->next();
1.383 + }
1.384 +
1.385 + guarantee(tail() == prev0, err_msg("Expected %s to end with %u but it ended with %u.", name(), tail()->hrs_index(), prev0->hrs_index()));
1.386 + guarantee(_tail == NULL || _tail->next() == NULL, "_tail should not have a next");
1.387 + guarantee(length() == count, err_msg("%s count mismatch. Expected %u, actual %u.", name(), length(), count));
1.388 + guarantee(total_capacity_bytes() == capacity, err_msg("%s capacity mismatch. Expected " SIZE_FORMAT ", actual " SIZE_FORMAT,
1.389 + name(), total_capacity_bytes(), capacity));
1.390 +}
1.391 +
1.392 +// Note on the check_mt_safety() methods below:
1.393 +//
1.394 +// Verification of the "master" heap region sets / lists that are
1.395 +// maintained by G1CollectedHeap is always done during a STW pause and
1.396 +// by the VM thread at the start / end of the pause. The standard
1.397 +// verification methods all assert check_mt_safety(). This is
1.398 +// important as it ensures that verification is done without
1.399 +// concurrent updates taking place at the same time. It follows, that,
1.400 +// for the "master" heap region sets / lists, the check_mt_safety()
1.401 +// method should include the VM thread / STW case.
1.402 +
1.403 +void MasterFreeRegionListMtSafeChecker::check() {
1.404 + // Master Free List MT safety protocol:
1.405 + // (a) If we're at a safepoint, operations on the master free list
1.406 + // should be invoked by either the VM thread (which will serialize
1.407 + // them) or by the GC workers while holding the
1.408 + // FreeList_lock.
1.409 + // (b) If we're not at a safepoint, operations on the master free
1.410 + // list should be invoked while holding the Heap_lock.
1.411 +
1.412 + if (SafepointSynchronize::is_at_safepoint()) {
1.413 + guarantee(Thread::current()->is_VM_thread() ||
1.414 + FreeList_lock->owned_by_self(), "master free list MT safety protocol at a safepoint");
1.415 + } else {
1.416 + guarantee(Heap_lock->owned_by_self(), "master free list MT safety protocol outside a safepoint");
1.417 + }
1.418 +}
1.419 +
1.420 +void SecondaryFreeRegionListMtSafeChecker::check() {
1.421 + // Secondary Free List MT safety protocol:
1.422 + // Operations on the secondary free list should always be invoked
1.423 + // while holding the SecondaryFreeList_lock.
1.424 +
1.425 + guarantee(SecondaryFreeList_lock->owned_by_self(), "secondary free list MT safety protocol");
1.426 +}
1.427 +
1.428 +void OldRegionSetMtSafeChecker::check() {
1.429 + // Master Old Set MT safety protocol:
1.430 + // (a) If we're at a safepoint, operations on the master old set
1.431 + // should be invoked:
1.432 + // - by the VM thread (which will serialize them), or
1.433 + // - by the GC workers while holding the FreeList_lock, if we're
1.434 + // at a safepoint for an evacuation pause (this lock is taken
1.435 + // anyway when an GC alloc region is retired so that a new one
1.436 + // is allocated from the free list), or
1.437 + // - by the GC workers while holding the OldSets_lock, if we're at a
1.438 + // safepoint for a cleanup pause.
1.439 + // (b) If we're not at a safepoint, operations on the master old set
1.440 + // should be invoked while holding the Heap_lock.
1.441 +
1.442 + if (SafepointSynchronize::is_at_safepoint()) {
1.443 + guarantee(Thread::current()->is_VM_thread()
1.444 + || FreeList_lock->owned_by_self() || OldSets_lock->owned_by_self(),
1.445 + "master old set MT safety protocol at a safepoint");
1.446 + } else {
1.447 + guarantee(Heap_lock->owned_by_self(), "master old set MT safety protocol outside a safepoint");
1.448 + }
1.449 +}
1.450 +
1.451 +void HumongousRegionSetMtSafeChecker::check() {
1.452 + // Humongous Set MT safety protocol:
1.453 + // (a) If we're at a safepoint, operations on the master humongous
1.454 + // set should be invoked by either the VM thread (which will
1.455 + // serialize them) or by the GC workers while holding the
1.456 + // OldSets_lock.
1.457 + // (b) If we're not at a safepoint, operations on the master
1.458 + // humongous set should be invoked while holding the Heap_lock.
1.459 +
1.460 + if (SafepointSynchronize::is_at_safepoint()) {
1.461 + guarantee(Thread::current()->is_VM_thread() ||
1.462 + OldSets_lock->owned_by_self(),
1.463 + "master humongous set MT safety protocol at a safepoint");
1.464 + } else {
1.465 + guarantee(Heap_lock->owned_by_self(),
1.466 + "master humongous set MT safety protocol outside a safepoint");
1.467 + }
1.468 +}
