aoqi@0: /*
aoqi@0:  * Copyright (c) 2011, 2014, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  *
aoqi@0:  */
aoqi@0: 
aoqi@0: #include "precompiled.hpp"
aoqi@0: #include "gc_implementation/g1/heapRegionRemSet.hpp"
aoqi@0: #include "gc_implementation/g1/heapRegionSet.inline.hpp"
aoqi@0: 
aoqi@0: PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
aoqi@0: 
aoqi@0: uint FreeRegionList::_unrealistically_long_length = 0;
aoqi@0: 
aoqi@0: void HeapRegionSetBase::fill_in_ext_msg(hrs_ext_msg* msg, const char* message) {
aoqi@0:   msg->append("[%s] %s ln: %u cy: "SIZE_FORMAT,
aoqi@0:               name(), message, length(), total_capacity_bytes());
aoqi@0:   fill_in_ext_msg_extra(msg);
aoqi@0: }
aoqi@0: 
aoqi@0: #ifndef PRODUCT
aoqi@0: void HeapRegionSetBase::verify_region(HeapRegion* hr) {
aoqi@0:   assert(hr->containing_set() == this, err_msg("Inconsistent containing set for %u", hr->hrs_index()));
aoqi@0:   assert(!hr->is_young(), err_msg("Adding young region %u", hr->hrs_index())); // currently we don't use these sets for young regions
aoqi@0:   assert(hr->isHumongous() == regions_humongous(), err_msg("Wrong humongous state for region %u and set %s", hr->hrs_index(), name()));
aoqi@0:   assert(hr->is_empty() == regions_empty(), err_msg("Wrong empty state for region %u and set %s", hr->hrs_index(), name()));
aoqi@0:   assert(hr->rem_set()->verify_ready_for_par_iteration(), err_msg("Wrong iteration state %u", hr->hrs_index()));
aoqi@0: }
aoqi@0: #endif
aoqi@0: 
aoqi@0: void HeapRegionSetBase::verify() {
aoqi@0:   // It's important that we also observe the MT safety protocol even
aoqi@0:   // for the verification calls. If we do verification without the
aoqi@0:   // appropriate locks and the set changes underneath our feet
aoqi@0:   // verification might fail and send us on a wild goose chase.
aoqi@0:   check_mt_safety();
aoqi@0: 
aoqi@0:   guarantee(( is_empty() && length() == 0 && total_capacity_bytes() == 0) ||
aoqi@0:             (!is_empty() && length() >= 0 && total_capacity_bytes() >= 0),
aoqi@0:             hrs_ext_msg(this, "invariant"));
aoqi@0: }
aoqi@0: 
aoqi@0: void HeapRegionSetBase::verify_start() {
aoqi@0:   // See comment in verify() about MT safety and verification.
aoqi@0:   check_mt_safety();
aoqi@0:   assert(!_verify_in_progress,
aoqi@0:          hrs_ext_msg(this, "verification should not be in progress"));
aoqi@0: 
aoqi@0:   // Do the basic verification first before we do the checks over the regions.
aoqi@0:   HeapRegionSetBase::verify();
aoqi@0: 
aoqi@0:   _verify_in_progress        = true;
aoqi@0: }
aoqi@0: 
aoqi@0: void HeapRegionSetBase::verify_end() {
aoqi@0:   // See comment in verify() about MT safety and verification.
aoqi@0:   check_mt_safety();
aoqi@0:   assert(_verify_in_progress,
aoqi@0:          hrs_ext_msg(this, "verification should be in progress"));
aoqi@0: 
aoqi@0:   _verify_in_progress = false;
aoqi@0: }
aoqi@0: 
aoqi@0: void HeapRegionSetBase::print_on(outputStream* out, bool print_contents) {
aoqi@0:   out->cr();
aoqi@0:   out->print_cr("Set: %s ("PTR_FORMAT")", name(), this);
aoqi@0:   out->print_cr("  Region Assumptions");
aoqi@0:   out->print_cr("    humongous         : %s", BOOL_TO_STR(regions_humongous()));
aoqi@0:   out->print_cr("    empty             : %s", BOOL_TO_STR(regions_empty()));
aoqi@0:   out->print_cr("  Attributes");
aoqi@0:   out->print_cr("    length            : %14u", length());
aoqi@0:   out->print_cr("    total capacity    : "SIZE_FORMAT_W(14)" bytes",
aoqi@0:                 total_capacity_bytes());
aoqi@0: }
aoqi@0: 
aoqi@0: HeapRegionSetBase::HeapRegionSetBase(const char* name, bool humongous, bool empty, HRSMtSafeChecker* mt_safety_checker)
aoqi@0:   : _name(name), _verify_in_progress(false),
aoqi@0:     _is_humongous(humongous), _is_empty(empty), _mt_safety_checker(mt_safety_checker),
aoqi@0:     _count()
aoqi@0: { }
aoqi@0: 
aoqi@0: void FreeRegionList::set_unrealistically_long_length(uint len) {
aoqi@0:   guarantee(_unrealistically_long_length == 0, "should only be set once");
aoqi@0:   _unrealistically_long_length = len;
aoqi@0: }
aoqi@0: 
aoqi@0: void FreeRegionList::fill_in_ext_msg_extra(hrs_ext_msg* msg) {
aoqi@0:   msg->append(" hd: "PTR_FORMAT" tl: "PTR_FORMAT, head(), tail());
aoqi@0: }
aoqi@0: 
aoqi@0: void FreeRegionList::add_as_head_or_tail(FreeRegionList* from_list, bool as_head) {
aoqi@0:   check_mt_safety();
aoqi@0:   from_list->check_mt_safety();
aoqi@0: 
aoqi@0:   verify_optional();
aoqi@0:   from_list->verify_optional();
aoqi@0: 
aoqi@0:   if (from_list->is_empty()) {
aoqi@0:     return;
aoqi@0:   }
aoqi@0: 
aoqi@0: #ifdef ASSERT
aoqi@0:   FreeRegionListIterator iter(from_list);
aoqi@0:   while (iter.more_available()) {
aoqi@0:     HeapRegion* hr = iter.get_next();
aoqi@0:     // In set_containing_set() we check that we either set the value
aoqi@0:     // from NULL to non-NULL or vice versa to catch bugs. So, we have
aoqi@0:     // to NULL it first before setting it to the value.
aoqi@0:     hr->set_containing_set(NULL);
aoqi@0:     hr->set_containing_set(this);
aoqi@0:   }
aoqi@0: #endif // ASSERT
aoqi@0: 
aoqi@0:   if (_head == NULL) {
aoqi@0:     assert(length() == 0 && _tail == NULL, hrs_ext_msg(this, "invariant"));
aoqi@0:     _head = from_list->_head;
aoqi@0:     _tail = from_list->_tail;
aoqi@0:   } else {
aoqi@0:     assert(length() > 0 && _tail != NULL, hrs_ext_msg(this, "invariant"));
aoqi@0:     if (as_head) {
aoqi@0:       from_list->_tail->set_next(_head);
aoqi@0:       _head->set_prev(from_list->_tail);
aoqi@0:       _head = from_list->_head;
aoqi@0:     } else {
aoqi@0:       _tail->set_next(from_list->_head);
aoqi@0:       from_list->_head->set_prev(_tail);
aoqi@0:       _tail = from_list->_tail;
aoqi@0:     }
aoqi@0:   }
aoqi@0: 
aoqi@0:   _count.increment(from_list->length(), from_list->total_capacity_bytes());
aoqi@0:   from_list->clear();
aoqi@0: 
aoqi@0:   verify_optional();
aoqi@0:   from_list->verify_optional();
aoqi@0: }
aoqi@0: 
aoqi@0: void FreeRegionList::add_as_head(FreeRegionList* from_list) {
aoqi@0:   add_as_head_or_tail(from_list, true /* as_head */);
aoqi@0: }
aoqi@0: 
aoqi@0: void FreeRegionList::add_as_tail(FreeRegionList* from_list) {
aoqi@0:   add_as_head_or_tail(from_list, false /* as_head */);
aoqi@0: }
aoqi@0: 
aoqi@0: void FreeRegionList::remove_all() {
aoqi@0:   check_mt_safety();
aoqi@0:   verify_optional();
aoqi@0: 
aoqi@0:   HeapRegion* curr = _head;
aoqi@0:   while (curr != NULL) {
aoqi@0:     verify_region(curr);
aoqi@0: 
aoqi@0:     HeapRegion* next = curr->next();
aoqi@0:     curr->set_next(NULL);
aoqi@0:     curr->set_prev(NULL);
aoqi@0:     curr->set_containing_set(NULL);
aoqi@0:     curr = next;
aoqi@0:   }
aoqi@0:   clear();
aoqi@0: 
aoqi@0:   verify_optional();
aoqi@0: }
aoqi@0: 
aoqi@0: void FreeRegionList::add_ordered(FreeRegionList* from_list) {
aoqi@0:   check_mt_safety();
aoqi@0:   from_list->check_mt_safety();
aoqi@0: 
aoqi@0:   verify_optional();
aoqi@0:   from_list->verify_optional();
aoqi@0: 
aoqi@0:   if (from_list->is_empty()) {
aoqi@0:     return;
aoqi@0:   }
aoqi@0: 
aoqi@0:   if (is_empty()) {
aoqi@0:     add_as_head(from_list);
aoqi@0:     return;
aoqi@0:   }
aoqi@0: 
aoqi@0:   #ifdef ASSERT
aoqi@0:   FreeRegionListIterator iter(from_list);
aoqi@0:   while (iter.more_available()) {
aoqi@0:     HeapRegion* hr = iter.get_next();
aoqi@0:     // In set_containing_set() we check that we either set the value
aoqi@0:     // from NULL to non-NULL or vice versa to catch bugs. So, we have
aoqi@0:     // to NULL it first before setting it to the value.
aoqi@0:     hr->set_containing_set(NULL);
aoqi@0:     hr->set_containing_set(this);
aoqi@0:   }
aoqi@0:   #endif // ASSERT
aoqi@0: 
aoqi@0:   HeapRegion* curr_to = _head;
aoqi@0:   HeapRegion* curr_from = from_list->_head;
aoqi@0: 
aoqi@0:   while (curr_from != NULL) {
aoqi@0:     while (curr_to != NULL && curr_to->hrs_index() < curr_from->hrs_index()) {
aoqi@0:       curr_to = curr_to->next();
aoqi@0:     }
aoqi@0: 
aoqi@0:     if (curr_to == NULL) {
aoqi@0:       // The rest of the from list should be added as tail
aoqi@0:       _tail->set_next(curr_from);
aoqi@0:       curr_from->set_prev(_tail);
aoqi@0:       curr_from = NULL;
aoqi@0:     } else {
aoqi@0:       HeapRegion* next_from = curr_from->next();
aoqi@0: 
aoqi@0:       curr_from->set_next(curr_to);
aoqi@0:       curr_from->set_prev(curr_to->prev());
aoqi@0:       if (curr_to->prev() == NULL) {
aoqi@0:         _head = curr_from;
aoqi@0:       } else {
aoqi@0:         curr_to->prev()->set_next(curr_from);
aoqi@0:       }
aoqi@0:       curr_to->set_prev(curr_from);
aoqi@0: 
aoqi@0:       curr_from = next_from;
aoqi@0:     }
aoqi@0:   }
aoqi@0: 
aoqi@0:   if (_tail->hrs_index() < from_list->_tail->hrs_index()) {
aoqi@0:     _tail = from_list->_tail;
aoqi@0:   }
aoqi@0: 
aoqi@0:   _count.increment(from_list->length(), from_list->total_capacity_bytes());
aoqi@0:   from_list->clear();
aoqi@0: 
aoqi@0:   verify_optional();
aoqi@0:   from_list->verify_optional();
aoqi@0: }
aoqi@0: 
aoqi@0: void FreeRegionList::remove_all_pending(uint target_count) {
aoqi@0:   check_mt_safety();
aoqi@0:   assert(target_count > 1, hrs_ext_msg(this, "pre-condition"));
aoqi@0:   assert(!is_empty(), hrs_ext_msg(this, "pre-condition"));
aoqi@0: 
aoqi@0:   verify_optional();
aoqi@0:   DEBUG_ONLY(uint old_length = length();)
aoqi@0: 
aoqi@0:   HeapRegion* curr = _head;
aoqi@0:   uint count = 0;
aoqi@0:   while (curr != NULL) {
aoqi@0:     verify_region(curr);
aoqi@0:     HeapRegion* next = curr->next();
aoqi@0:     HeapRegion* prev = curr->prev();
aoqi@0: 
aoqi@0:     if (curr->pending_removal()) {
aoqi@0:       assert(count < target_count,
aoqi@0:              hrs_err_msg("[%s] should not come across more regions "
aoqi@0:                          "pending for removal than target_count: %u",
aoqi@0:                          name(), target_count));
aoqi@0: 
aoqi@0:       if (prev == NULL) {
aoqi@0:         assert(_head == curr, hrs_ext_msg(this, "invariant"));
aoqi@0:         _head = next;
aoqi@0:       } else {
aoqi@0:         assert(_head != curr, hrs_ext_msg(this, "invariant"));
aoqi@0:         prev->set_next(next);
aoqi@0:       }
aoqi@0:       if (next == NULL) {
aoqi@0:         assert(_tail == curr, hrs_ext_msg(this, "invariant"));
aoqi@0:         _tail = prev;
aoqi@0:       } else {
aoqi@0:         assert(_tail != curr, hrs_ext_msg(this, "invariant"));
aoqi@0:         next->set_prev(prev);
aoqi@0:       }
aoqi@0:       if (_last = curr) {
aoqi@0:         _last = NULL;
aoqi@0:       }
aoqi@0: 
aoqi@0:       curr->set_next(NULL);
aoqi@0:       curr->set_prev(NULL);
aoqi@0:       remove(curr);
aoqi@0:       curr->set_pending_removal(false);
aoqi@0: 
aoqi@0:       count += 1;
aoqi@0: 
aoqi@0:       // If we have come across the target number of regions we can
aoqi@0:       // just bail out. However, for debugging purposes, we can just
aoqi@0:       // carry on iterating to make sure there are not more regions
aoqi@0:       // tagged with pending removal.
aoqi@0:       DEBUG_ONLY(if (count == target_count) break;)
aoqi@0:     }
aoqi@0:     curr = next;
aoqi@0:   }
aoqi@0: 
aoqi@0:   assert(count == target_count,
aoqi@0:          hrs_err_msg("[%s] count: %u should be == target_count: %u",
aoqi@0:                      name(), count, target_count));
aoqi@0:   assert(length() + target_count == old_length,
aoqi@0:          hrs_err_msg("[%s] new length should be consistent "
aoqi@0:                      "new length: %u old length: %u target_count: %u",
aoqi@0:                      name(), length(), old_length, target_count));
aoqi@0: 
aoqi@0:   verify_optional();
aoqi@0: }
aoqi@0: 
aoqi@0: void FreeRegionList::verify() {
aoqi@0:   // See comment in HeapRegionSetBase::verify() about MT safety and
aoqi@0:   // verification.
aoqi@0:   check_mt_safety();
aoqi@0: 
aoqi@0:   // This will also do the basic verification too.
aoqi@0:   verify_start();
aoqi@0: 
aoqi@0:   verify_list();
aoqi@0: 
aoqi@0:   verify_end();
aoqi@0: }
aoqi@0: 
aoqi@0: void FreeRegionList::clear() {
aoqi@0:   _count = HeapRegionSetCount();
aoqi@0:   _head = NULL;
aoqi@0:   _tail = NULL;
aoqi@0:   _last = NULL;
aoqi@0: }
aoqi@0: 
aoqi@0: void FreeRegionList::print_on(outputStream* out, bool print_contents) {
aoqi@0:   HeapRegionSetBase::print_on(out, print_contents);
aoqi@0:   out->print_cr("  Linking");
aoqi@0:   out->print_cr("    head              : "PTR_FORMAT, _head);
aoqi@0:   out->print_cr("    tail              : "PTR_FORMAT, _tail);
aoqi@0: 
aoqi@0:   if (print_contents) {
aoqi@0:     out->print_cr("  Contents");
aoqi@0:     FreeRegionListIterator iter(this);
aoqi@0:     while (iter.more_available()) {
aoqi@0:       HeapRegion* hr = iter.get_next();
aoqi@0:       hr->print_on(out);
aoqi@0:     }
aoqi@0:   }
aoqi@0: }
aoqi@0: 
aoqi@0: void FreeRegionList::verify_list() {
aoqi@0:   HeapRegion* curr = head();
aoqi@0:   HeapRegion* prev1 = NULL;
aoqi@0:   HeapRegion* prev0 = NULL;
aoqi@0:   uint count = 0;
aoqi@0:   size_t capacity = 0;
aoqi@0:   uint last_index = 0;
aoqi@0: 
aoqi@0:   guarantee(_head == NULL || _head->prev() == NULL, "_head should not have a prev");
aoqi@0:   while (curr != NULL) {
aoqi@0:     verify_region(curr);
aoqi@0: 
aoqi@0:     count++;
aoqi@0:     guarantee(count < _unrealistically_long_length,
aoqi@0:         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()));
aoqi@0: 
aoqi@0:     if (curr->next() != NULL) {
aoqi@0:       guarantee(curr->next()->prev() == curr, "Next or prev pointers messed up");
aoqi@0:     }
aoqi@0:     guarantee(curr->hrs_index() == 0 || curr->hrs_index() > last_index, "List should be sorted");
aoqi@0:     last_index = curr->hrs_index();
aoqi@0: 
aoqi@0:     capacity += curr->capacity();
aoqi@0: 
aoqi@0:     prev1 = prev0;
aoqi@0:     prev0 = curr;
aoqi@0:     curr = curr->next();
aoqi@0:   }
aoqi@0: 
aoqi@0:   guarantee(tail() == prev0, err_msg("Expected %s to end with %u but it ended with %u.", name(), tail()->hrs_index(), prev0->hrs_index()));
aoqi@0:   guarantee(_tail == NULL || _tail->next() == NULL, "_tail should not have a next");
aoqi@0:   guarantee(length() == count, err_msg("%s count mismatch. Expected %u, actual %u.", name(), length(), count));
aoqi@0:   guarantee(total_capacity_bytes() == capacity, err_msg("%s capacity mismatch. Expected " SIZE_FORMAT ", actual " SIZE_FORMAT,
aoqi@0:       name(), total_capacity_bytes(), capacity));
aoqi@0: }
aoqi@0: 
aoqi@0: // Note on the check_mt_safety() methods below:
aoqi@0: //
aoqi@0: // Verification of the "master" heap region sets / lists that are
aoqi@0: // maintained by G1CollectedHeap is always done during a STW pause and
aoqi@0: // by the VM thread at the start / end of the pause. The standard
aoqi@0: // verification methods all assert check_mt_safety(). This is
aoqi@0: // important as it ensures that verification is done without
aoqi@0: // concurrent updates taking place at the same time. It follows, that,
aoqi@0: // for the "master" heap region sets / lists, the check_mt_safety()
aoqi@0: // method should include the VM thread / STW case.
aoqi@0: 
aoqi@0: void MasterFreeRegionListMtSafeChecker::check() {
aoqi@0:   // Master Free List MT safety protocol:
aoqi@0:   // (a) If we're at a safepoint, operations on the master free list
aoqi@0:   // should be invoked by either the VM thread (which will serialize
aoqi@0:   // them) or by the GC workers while holding the
aoqi@0:   // FreeList_lock.
aoqi@0:   // (b) If we're not at a safepoint, operations on the master free
aoqi@0:   // list should be invoked while holding the Heap_lock.
aoqi@0: 
aoqi@0:   if (SafepointSynchronize::is_at_safepoint()) {
aoqi@0:     guarantee(Thread::current()->is_VM_thread() ||
aoqi@0:               FreeList_lock->owned_by_self(), "master free list MT safety protocol at a safepoint");
aoqi@0:   } else {
aoqi@0:     guarantee(Heap_lock->owned_by_self(), "master free list MT safety protocol outside a safepoint");
aoqi@0:   }
aoqi@0: }
aoqi@0: 
aoqi@0: void SecondaryFreeRegionListMtSafeChecker::check() {
aoqi@0:   // Secondary Free List MT safety protocol:
aoqi@0:   // Operations on the secondary free list should always be invoked
aoqi@0:   // while holding the SecondaryFreeList_lock.
aoqi@0: 
aoqi@0:   guarantee(SecondaryFreeList_lock->owned_by_self(), "secondary free list MT safety protocol");
aoqi@0: }
aoqi@0: 
aoqi@0: void OldRegionSetMtSafeChecker::check() {
aoqi@0:   // Master Old Set MT safety protocol:
aoqi@0:   // (a) If we're at a safepoint, operations on the master old set
aoqi@0:   // should be invoked:
aoqi@0:   // - by the VM thread (which will serialize them), or
aoqi@0:   // - by the GC workers while holding the FreeList_lock, if we're
aoqi@0:   //   at a safepoint for an evacuation pause (this lock is taken
aoqi@0:   //   anyway when an GC alloc region is retired so that a new one
aoqi@0:   //   is allocated from the free list), or
aoqi@0:   // - by the GC workers while holding the OldSets_lock, if we're at a
aoqi@0:   //   safepoint for a cleanup pause.
aoqi@0:   // (b) If we're not at a safepoint, operations on the master old set
aoqi@0:   // should be invoked while holding the Heap_lock.
aoqi@0: 
aoqi@0:   if (SafepointSynchronize::is_at_safepoint()) {
aoqi@0:     guarantee(Thread::current()->is_VM_thread()
aoqi@0:         || FreeList_lock->owned_by_self() || OldSets_lock->owned_by_self(),
aoqi@0:         "master old set MT safety protocol at a safepoint");
aoqi@0:   } else {
aoqi@0:     guarantee(Heap_lock->owned_by_self(), "master old set MT safety protocol outside a safepoint");
aoqi@0:   }
aoqi@0: }
aoqi@0: 
aoqi@0: void HumongousRegionSetMtSafeChecker::check() {
aoqi@0:   // Humongous Set MT safety protocol:
aoqi@0:   // (a) If we're at a safepoint, operations on the master humongous
aoqi@0:   // set should be invoked by either the VM thread (which will
aoqi@0:   // serialize them) or by the GC workers while holding the
aoqi@0:   // OldSets_lock.
aoqi@0:   // (b) If we're not at a safepoint, operations on the master
aoqi@0:   // humongous set should be invoked while holding the Heap_lock.
aoqi@0: 
aoqi@0:   if (SafepointSynchronize::is_at_safepoint()) {
aoqi@0:     guarantee(Thread::current()->is_VM_thread() ||
aoqi@0:               OldSets_lock->owned_by_self(),
aoqi@0:               "master humongous set MT safety protocol at a safepoint");
aoqi@0:   } else {
aoqi@0:     guarantee(Heap_lock->owned_by_self(),
aoqi@0:               "master humongous set MT safety protocol outside a safepoint");
aoqi@0:   }
aoqi@0: }