diff -r 000000000000 -r f90c822e73f8 src/share/vm/gc_implementation/g1/heapRegionSet.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/gc_implementation/g1/heapRegionSet.cpp Wed Apr 27 01:25:04 2016 +0800 @@ -0,0 +1,465 @@ +/* + * Copyright (c) 2011, 2014, Oracle and/or its affiliates. All rights reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA + * or visit www.oracle.com if you need additional information or have any + * questions. + * + */ + +#include "precompiled.hpp" +#include "gc_implementation/g1/heapRegionRemSet.hpp" +#include "gc_implementation/g1/heapRegionSet.inline.hpp" + +PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC + +uint FreeRegionList::_unrealistically_long_length = 0; + +void HeapRegionSetBase::fill_in_ext_msg(hrs_ext_msg* msg, const char* message) { + msg->append("[%s] %s ln: %u cy: "SIZE_FORMAT, + name(), message, length(), total_capacity_bytes()); + fill_in_ext_msg_extra(msg); +} + +#ifndef PRODUCT +void HeapRegionSetBase::verify_region(HeapRegion* hr) { + assert(hr->containing_set() == this, err_msg("Inconsistent containing set for %u", hr->hrs_index())); + assert(!hr->is_young(), err_msg("Adding young region %u", hr->hrs_index())); // currently we don't use these sets for young regions + assert(hr->isHumongous() == regions_humongous(), err_msg("Wrong humongous state for region %u and set %s", hr->hrs_index(), name())); + assert(hr->is_empty() == regions_empty(), err_msg("Wrong empty state for region %u and set %s", hr->hrs_index(), name())); + assert(hr->rem_set()->verify_ready_for_par_iteration(), err_msg("Wrong iteration state %u", hr->hrs_index())); +} +#endif + +void HeapRegionSetBase::verify() { + // It's important that we also observe the MT safety protocol even + // for the verification calls. If we do verification without the + // appropriate locks and the set changes underneath our feet + // verification might fail and send us on a wild goose chase. + check_mt_safety(); + + guarantee(( is_empty() && length() == 0 && total_capacity_bytes() == 0) || + (!is_empty() && length() >= 0 && total_capacity_bytes() >= 0), + hrs_ext_msg(this, "invariant")); +} + +void HeapRegionSetBase::verify_start() { + // See comment in verify() about MT safety and verification. + check_mt_safety(); + assert(!_verify_in_progress, + hrs_ext_msg(this, "verification should not be in progress")); + + // Do the basic verification first before we do the checks over the regions. + HeapRegionSetBase::verify(); + + _verify_in_progress = true; +} + +void HeapRegionSetBase::verify_end() { + // See comment in verify() about MT safety and verification. + check_mt_safety(); + assert(_verify_in_progress, + hrs_ext_msg(this, "verification should be in progress")); + + _verify_in_progress = false; +} + +void HeapRegionSetBase::print_on(outputStream* out, bool print_contents) { + out->cr(); + out->print_cr("Set: %s ("PTR_FORMAT")", name(), this); + out->print_cr(" Region Assumptions"); + out->print_cr(" humongous : %s", BOOL_TO_STR(regions_humongous())); + out->print_cr(" empty : %s", BOOL_TO_STR(regions_empty())); + out->print_cr(" Attributes"); + out->print_cr(" length : %14u", length()); + out->print_cr(" total capacity : "SIZE_FORMAT_W(14)" bytes", + total_capacity_bytes()); +} + +HeapRegionSetBase::HeapRegionSetBase(const char* name, bool humongous, bool empty, HRSMtSafeChecker* mt_safety_checker) + : _name(name), _verify_in_progress(false), + _is_humongous(humongous), _is_empty(empty), _mt_safety_checker(mt_safety_checker), + _count() +{ } + +void FreeRegionList::set_unrealistically_long_length(uint len) { + guarantee(_unrealistically_long_length == 0, "should only be set once"); + _unrealistically_long_length = len; +} + +void FreeRegionList::fill_in_ext_msg_extra(hrs_ext_msg* msg) { + msg->append(" hd: "PTR_FORMAT" tl: "PTR_FORMAT, head(), tail()); +} + +void FreeRegionList::add_as_head_or_tail(FreeRegionList* from_list, bool as_head) { + check_mt_safety(); + from_list->check_mt_safety(); + + verify_optional(); + from_list->verify_optional(); + + if (from_list->is_empty()) { + return; + } + +#ifdef ASSERT + FreeRegionListIterator iter(from_list); + while (iter.more_available()) { + HeapRegion* hr = iter.get_next(); + // In set_containing_set() we check that we either set the value + // from NULL to non-NULL or vice versa to catch bugs. So, we have + // to NULL it first before setting it to the value. + hr->set_containing_set(NULL); + hr->set_containing_set(this); + } +#endif // ASSERT + + if (_head == NULL) { + assert(length() == 0 && _tail == NULL, hrs_ext_msg(this, "invariant")); + _head = from_list->_head; + _tail = from_list->_tail; + } else { + assert(length() > 0 && _tail != NULL, hrs_ext_msg(this, "invariant")); + if (as_head) { + from_list->_tail->set_next(_head); + _head->set_prev(from_list->_tail); + _head = from_list->_head; + } else { + _tail->set_next(from_list->_head); + from_list->_head->set_prev(_tail); + _tail = from_list->_tail; + } + } + + _count.increment(from_list->length(), from_list->total_capacity_bytes()); + from_list->clear(); + + verify_optional(); + from_list->verify_optional(); +} + +void FreeRegionList::add_as_head(FreeRegionList* from_list) { + add_as_head_or_tail(from_list, true /* as_head */); +} + +void FreeRegionList::add_as_tail(FreeRegionList* from_list) { + add_as_head_or_tail(from_list, false /* as_head */); +} + +void FreeRegionList::remove_all() { + check_mt_safety(); + verify_optional(); + + HeapRegion* curr = _head; + while (curr != NULL) { + verify_region(curr); + + HeapRegion* next = curr->next(); + curr->set_next(NULL); + curr->set_prev(NULL); + curr->set_containing_set(NULL); + curr = next; + } + clear(); + + verify_optional(); +} + +void FreeRegionList::add_ordered(FreeRegionList* from_list) { + check_mt_safety(); + from_list->check_mt_safety(); + + verify_optional(); + from_list->verify_optional(); + + if (from_list->is_empty()) { + return; + } + + if (is_empty()) { + add_as_head(from_list); + return; + } + + #ifdef ASSERT + FreeRegionListIterator iter(from_list); + while (iter.more_available()) { + HeapRegion* hr = iter.get_next(); + // In set_containing_set() we check that we either set the value + // from NULL to non-NULL or vice versa to catch bugs. So, we have + // to NULL it first before setting it to the value. + hr->set_containing_set(NULL); + hr->set_containing_set(this); + } + #endif // ASSERT + + HeapRegion* curr_to = _head; + HeapRegion* curr_from = from_list->_head; + + while (curr_from != NULL) { + while (curr_to != NULL && curr_to->hrs_index() < curr_from->hrs_index()) { + curr_to = curr_to->next(); + } + + if (curr_to == NULL) { + // The rest of the from list should be added as tail + _tail->set_next(curr_from); + curr_from->set_prev(_tail); + curr_from = NULL; + } else { + HeapRegion* next_from = curr_from->next(); + + curr_from->set_next(curr_to); + curr_from->set_prev(curr_to->prev()); + if (curr_to->prev() == NULL) { + _head = curr_from; + } else { + curr_to->prev()->set_next(curr_from); + } + curr_to->set_prev(curr_from); + + curr_from = next_from; + } + } + + if (_tail->hrs_index() < from_list->_tail->hrs_index()) { + _tail = from_list->_tail; + } + + _count.increment(from_list->length(), from_list->total_capacity_bytes()); + from_list->clear(); + + verify_optional(); + from_list->verify_optional(); +} + +void FreeRegionList::remove_all_pending(uint target_count) { + check_mt_safety(); + assert(target_count > 1, hrs_ext_msg(this, "pre-condition")); + assert(!is_empty(), hrs_ext_msg(this, "pre-condition")); + + verify_optional(); + DEBUG_ONLY(uint old_length = length();) + + HeapRegion* curr = _head; + uint count = 0; + while (curr != NULL) { + verify_region(curr); + HeapRegion* next = curr->next(); + HeapRegion* prev = curr->prev(); + + if (curr->pending_removal()) { + assert(count < target_count, + hrs_err_msg("[%s] should not come across more regions " + "pending for removal than target_count: %u", + name(), target_count)); + + if (prev == NULL) { + assert(_head == curr, hrs_ext_msg(this, "invariant")); + _head = next; + } else { + assert(_head != curr, hrs_ext_msg(this, "invariant")); + prev->set_next(next); + } + if (next == NULL) { + assert(_tail == curr, hrs_ext_msg(this, "invariant")); + _tail = prev; + } else { + assert(_tail != curr, hrs_ext_msg(this, "invariant")); + next->set_prev(prev); + } + if (_last = curr) { + _last = NULL; + } + + curr->set_next(NULL); + curr->set_prev(NULL); + remove(curr); + curr->set_pending_removal(false); + + count += 1; + + // If we have come across the target number of regions we can + // just bail out. However, for debugging purposes, we can just + // carry on iterating to make sure there are not more regions + // tagged with pending removal. + DEBUG_ONLY(if (count == target_count) break;) + } + curr = next; + } + + assert(count == target_count, + hrs_err_msg("[%s] count: %u should be == target_count: %u", + name(), count, target_count)); + assert(length() + target_count == old_length, + hrs_err_msg("[%s] new length should be consistent " + "new length: %u old length: %u target_count: %u", + name(), length(), old_length, target_count)); + + verify_optional(); +} + +void FreeRegionList::verify() { + // See comment in HeapRegionSetBase::verify() about MT safety and + // verification. + check_mt_safety(); + + // This will also do the basic verification too. + verify_start(); + + verify_list(); + + verify_end(); +} + +void FreeRegionList::clear() { + _count = HeapRegionSetCount(); + _head = NULL; + _tail = NULL; + _last = NULL; +} + +void FreeRegionList::print_on(outputStream* out, bool print_contents) { + HeapRegionSetBase::print_on(out, print_contents); + out->print_cr(" Linking"); + out->print_cr(" head : "PTR_FORMAT, _head); + out->print_cr(" tail : "PTR_FORMAT, _tail); + + if (print_contents) { + out->print_cr(" Contents"); + FreeRegionListIterator iter(this); + while (iter.more_available()) { + HeapRegion* hr = iter.get_next(); + hr->print_on(out); + } + } +} + +void FreeRegionList::verify_list() { + HeapRegion* curr = head(); + HeapRegion* prev1 = NULL; + HeapRegion* prev0 = NULL; + uint count = 0; + size_t capacity = 0; + uint last_index = 0; + + guarantee(_head == NULL || _head->prev() == NULL, "_head should not have a prev"); + while (curr != NULL) { + verify_region(curr); + + count++; + guarantee(count < _unrealistically_long_length, + 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())); + + if (curr->next() != NULL) { + guarantee(curr->next()->prev() == curr, "Next or prev pointers messed up"); + } + guarantee(curr->hrs_index() == 0 || curr->hrs_index() > last_index, "List should be sorted"); + last_index = curr->hrs_index(); + + capacity += curr->capacity(); + + prev1 = prev0; + prev0 = curr; + curr = curr->next(); + } + + guarantee(tail() == prev0, err_msg("Expected %s to end with %u but it ended with %u.", name(), tail()->hrs_index(), prev0->hrs_index())); + guarantee(_tail == NULL || _tail->next() == NULL, "_tail should not have a next"); + guarantee(length() == count, err_msg("%s count mismatch. Expected %u, actual %u.", name(), length(), count)); + guarantee(total_capacity_bytes() == capacity, err_msg("%s capacity mismatch. Expected " SIZE_FORMAT ", actual " SIZE_FORMAT, + name(), total_capacity_bytes(), capacity)); +} + +// Note on the check_mt_safety() methods below: +// +// Verification of the "master" heap region sets / lists that are +// maintained by G1CollectedHeap is always done during a STW pause and +// by the VM thread at the start / end of the pause. The standard +// verification methods all assert check_mt_safety(). This is +// important as it ensures that verification is done without +// concurrent updates taking place at the same time. It follows, that, +// for the "master" heap region sets / lists, the check_mt_safety() +// method should include the VM thread / STW case. + +void MasterFreeRegionListMtSafeChecker::check() { + // Master Free List MT safety protocol: + // (a) If we're at a safepoint, operations on the master free list + // should be invoked by either the VM thread (which will serialize + // them) or by the GC workers while holding the + // FreeList_lock. + // (b) If we're not at a safepoint, operations on the master free + // list should be invoked while holding the Heap_lock. + + if (SafepointSynchronize::is_at_safepoint()) { + guarantee(Thread::current()->is_VM_thread() || + FreeList_lock->owned_by_self(), "master free list MT safety protocol at a safepoint"); + } else { + guarantee(Heap_lock->owned_by_self(), "master free list MT safety protocol outside a safepoint"); + } +} + +void SecondaryFreeRegionListMtSafeChecker::check() { + // Secondary Free List MT safety protocol: + // Operations on the secondary free list should always be invoked + // while holding the SecondaryFreeList_lock. + + guarantee(SecondaryFreeList_lock->owned_by_self(), "secondary free list MT safety protocol"); +} + +void OldRegionSetMtSafeChecker::check() { + // Master Old Set MT safety protocol: + // (a) If we're at a safepoint, operations on the master old set + // should be invoked: + // - by the VM thread (which will serialize them), or + // - by the GC workers while holding the FreeList_lock, if we're + // at a safepoint for an evacuation pause (this lock is taken + // anyway when an GC alloc region is retired so that a new one + // is allocated from the free list), or + // - by the GC workers while holding the OldSets_lock, if we're at a + // safepoint for a cleanup pause. + // (b) If we're not at a safepoint, operations on the master old set + // should be invoked while holding the Heap_lock. + + if (SafepointSynchronize::is_at_safepoint()) { + guarantee(Thread::current()->is_VM_thread() + || FreeList_lock->owned_by_self() || OldSets_lock->owned_by_self(), + "master old set MT safety protocol at a safepoint"); + } else { + guarantee(Heap_lock->owned_by_self(), "master old set MT safety protocol outside a safepoint"); + } +} + +void HumongousRegionSetMtSafeChecker::check() { + // Humongous Set MT safety protocol: + // (a) If we're at a safepoint, operations on the master humongous + // set should be invoked by either the VM thread (which will + // serialize them) or by the GC workers while holding the + // OldSets_lock. + // (b) If we're not at a safepoint, operations on the master + // humongous set should be invoked while holding the Heap_lock. + + if (SafepointSynchronize::is_at_safepoint()) { + guarantee(Thread::current()->is_VM_thread() || + OldSets_lock->owned_by_self(), + "master humongous set MT safety protocol at a safepoint"); + } else { + guarantee(Heap_lock->owned_by_self(), + "master humongous set MT safety protocol outside a safepoint"); + } +}