--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc/g1/heapRegionSet.cpp Wed May 13 15:16:06 2015 +0200
@@ -0,0 +1,453 @@
+/*
+ * Copyright (c) 2011, 2015, 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/g1/g1CollectedHeap.inline.hpp"
+#include "gc/g1/heapRegionRemSet.hpp"
+#include "gc/g1/heapRegionSet.inline.hpp"
+
+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->hrm_index()));
+ assert(!hr->is_young(), err_msg("Adding young region %u", hr->hrm_index())); // currently we don't use these sets for young regions
+ assert(hr->is_humongous() == regions_humongous(), err_msg("Wrong humongous state for region %u and set %s", hr->hrm_index(), name()));
+ assert(hr->is_free() == regions_free(), err_msg("Wrong free state for region %u and set %s", hr->hrm_index(), name()));
+ assert(!hr->is_free() || hr->is_empty(), err_msg("Free region %u is not empty for set %s", hr->hrm_index(), name()));
+ assert(!hr->is_empty() || hr->is_free(), err_msg("Empty region %u is not free for set %s", hr->hrm_index(), name()));
+ assert(hr->rem_set()->verify_ready_for_par_iteration(), err_msg("Wrong iteration state %u", hr->hrm_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(), p2i(this));
+ out->print_cr(" Region Assumptions");
+ out->print_cr(" humongous : %s", BOOL_TO_STR(regions_humongous()));
+ out->print_cr(" free : %s", BOOL_TO_STR(regions_free()));
+ 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 free, HRSMtSafeChecker* mt_safety_checker)
+ : _name(name), _verify_in_progress(false),
+ _is_humongous(humongous), _is_free(free), _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, p2i(_head), p2i(_tail));
+}
+
+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;
+ }
+
+ #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 (is_empty()) {
+ assert(length() == 0 && _tail == NULL, hrs_ext_msg(this, "invariant"));
+ _head = from_list->_head;
+ _tail = from_list->_tail;
+ } else {
+ HeapRegion* curr_to = _head;
+ HeapRegion* curr_from = from_list->_head;
+
+ while (curr_from != NULL) {
+ while (curr_to != NULL && curr_to->hrm_index() < curr_from->hrm_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->hrm_index() < from_list->_tail->hrm_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_starting_at(HeapRegion* first, uint num_regions) {
+ check_mt_safety();
+ assert(num_regions >= 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 = first;
+ uint count = 0;
+ while (count < num_regions) {
+ verify_region(curr);
+ HeapRegion* next = curr->next();
+ HeapRegion* prev = curr->prev();
+
+ assert(count < num_regions,
+ hrs_err_msg("[%s] should not come across more regions "
+ "pending for removal than num_regions: %u",
+ name(), num_regions));
+
+ 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);
+
+ count++;
+ curr = next;
+ }
+
+ assert(count == num_regions,
+ hrs_err_msg("[%s] count: %u should be == num_regions: %u",
+ name(), count, num_regions));
+ assert(length() + num_regions == old_length,
+ hrs_err_msg("[%s] new length should be consistent "
+ "new length: %u old length: %u num_regions: %u",
+ name(), length(), old_length, num_regions));
+
+ 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, p2i(_head));
+ out->print_cr(" tail : "PTR_FORMAT, p2i(_tail));
+
+ if (print_contents) {
+ out->print_cr(" Contents");
+ FreeRegionListIterator iter(this);
+ while (iter.more_available()) {
+ HeapRegion* hr = iter.get_next();
+ hr->print_on(out);
+ }
+ }
+
+ out->cr();
+}
+
+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, p2i(curr), p2i(prev0), p2i(prev1), length()));
+
+ if (curr->next() != NULL) {
+ guarantee(curr->next()->prev() == curr, "Next or prev pointers messed up");
+ }
+ guarantee(curr->hrm_index() == 0 || curr->hrm_index() > last_index, "List should be sorted");
+ last_index = curr->hrm_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->hrm_index(), prev0->hrm_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");
+ }
+}
+
+void FreeRegionList_test() {
+ FreeRegionList l("test");
+
+ const uint num_regions_in_test = 5;
+ // Create a fake heap. It does not need to be valid, as the HeapRegion constructor
+ // does not access it.
+ MemRegion heap(NULL, num_regions_in_test * HeapRegion::GrainWords);
+ // Allocate a fake BOT because the HeapRegion constructor initializes
+ // the BOT.
+ size_t bot_size = G1BlockOffsetSharedArray::compute_size(heap.word_size());
+ HeapWord* bot_data = NEW_C_HEAP_ARRAY(HeapWord, bot_size, mtGC);
+ ReservedSpace bot_rs(G1BlockOffsetSharedArray::compute_size(heap.word_size()));
+ G1RegionToSpaceMapper* bot_storage =
+ G1RegionToSpaceMapper::create_mapper(bot_rs,
+ bot_rs.size(),
+ os::vm_page_size(),
+ HeapRegion::GrainBytes,
+ G1BlockOffsetSharedArray::N_bytes,
+ mtGC);
+ G1BlockOffsetSharedArray oa(heap, bot_storage);
+ bot_storage->commit_regions(0, num_regions_in_test);
+
+ // Set up memory regions for the heap regions.
+ MemRegion mr0(heap.start(), HeapRegion::GrainWords);
+ MemRegion mr1(mr0.end(), HeapRegion::GrainWords);
+ MemRegion mr2(mr1.end(), HeapRegion::GrainWords);
+ MemRegion mr3(mr2.end(), HeapRegion::GrainWords);
+ MemRegion mr4(mr3.end(), HeapRegion::GrainWords);
+
+ HeapRegion hr0(0, &oa, mr0);
+ HeapRegion hr1(1, &oa, mr1);
+ HeapRegion hr2(2, &oa, mr2);
+ HeapRegion hr3(3, &oa, mr3);
+ HeapRegion hr4(4, &oa, mr4);
+ l.add_ordered(&hr1);
+ l.add_ordered(&hr0);
+ l.add_ordered(&hr3);
+ l.add_ordered(&hr4);
+ l.add_ordered(&hr2);
+ assert(l.length() == num_regions_in_test, "wrong length");
+ l.verify_list();
+
+ bot_storage->uncommit_regions(0, num_regions_in_test);
+ delete bot_storage;
+ FREE_C_HEAP_ARRAY(HeapWord, bot_data);
+}