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/*
* Copyright (c) 1997, 2021, 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 "compiler/compileBroker.hpp"
#include "gc/serial/markSweep.inline.hpp"
#include "gc/shared/collectedHeap.inline.hpp"
#include "gc/shared/gcTimer.hpp"
#include "gc/shared/gcTrace.hpp"
#include "gc/shared/gc_globals.hpp"
#include "memory/iterator.inline.hpp"
#include "memory/universe.hpp"
#include "oops/access.inline.hpp"
#include "oops/compressedOops.inline.hpp"
#include "oops/instanceClassLoaderKlass.inline.hpp"
#include "oops/instanceKlass.inline.hpp"
#include "oops/instanceMirrorKlass.inline.hpp"
#include "oops/instanceRefKlass.inline.hpp"
#include "oops/methodData.hpp"
#include "oops/objArrayKlass.inline.hpp"
#include "oops/oop.inline.hpp"
#include "oops/typeArrayOop.inline.hpp"
#include "utilities/macros.hpp"
#include "utilities/stack.inline.hpp"
uint MarkSweep::_total_invocations = 0;
Stack<oop, mtGC> MarkSweep::_marking_stack;
Stack<ObjArrayTask, mtGC> MarkSweep::_objarray_stack;
Stack<PreservedMark, mtGC> MarkSweep::_preserved_overflow_stack;
size_t MarkSweep::_preserved_count = 0;
size_t MarkSweep::_preserved_count_max = 0;
PreservedMark* MarkSweep::_preserved_marks = NULL;
ReferenceProcessor* MarkSweep::_ref_processor = NULL;
STWGCTimer* MarkSweep::_gc_timer = NULL;
SerialOldTracer* MarkSweep::_gc_tracer = NULL;
StringDedup::Requests* MarkSweep::_string_dedup_requests = NULL;
MarkSweep::FollowRootClosure MarkSweep::follow_root_closure;
MarkAndPushClosure MarkSweep::mark_and_push_closure;
CLDToOopClosure MarkSweep::follow_cld_closure(&mark_and_push_closure, ClassLoaderData::_claim_stw_fullgc_mark);
CLDToOopClosure MarkSweep::adjust_cld_closure(&adjust_pointer_closure, ClassLoaderData::_claim_stw_fullgc_adjust);
template <class T> inline void MarkSweep::KeepAliveClosure::do_oop_work(T* p) {
mark_and_push(p);
}
void MarkSweep::push_objarray(oop obj, size_t index) {
ObjArrayTask task(obj, index);
assert(task.is_valid(), "bad ObjArrayTask");
_objarray_stack.push(task);
}
inline void MarkSweep::follow_array(objArrayOop array) {
MarkSweep::follow_klass(array->klass());
// Don't push empty arrays to avoid unnecessary work.
if (array->length() > 0) {
MarkSweep::push_objarray(array, 0);
}
}
inline void MarkSweep::follow_object(oop obj) {
assert(obj->is_gc_marked(), "should be marked");
if (obj->is_objArray()) {
// Handle object arrays explicitly to allow them to
// be split into chunks if needed.
MarkSweep::follow_array((objArrayOop)obj);
} else {
obj->oop_iterate(&mark_and_push_closure);
}
}
void MarkSweep::follow_array_chunk(objArrayOop array, int index) {
const int len = array->length();
const int beg_index = index;
assert(beg_index < len || len == 0, "index too large");
const int stride = MIN2(len - beg_index, (int) ObjArrayMarkingStride);
const int end_index = beg_index + stride;
array->oop_iterate_range(&mark_and_push_closure, beg_index, end_index);
if (end_index < len) {
MarkSweep::push_objarray(array, end_index); // Push the continuation.
}
}
void MarkSweep::follow_stack() {
do {
while (!_marking_stack.is_empty()) {
oop obj = _marking_stack.pop();
assert (obj->is_gc_marked(), "p must be marked");
follow_object(obj);
}
// Process ObjArrays one at a time to avoid marking stack bloat.
if (!_objarray_stack.is_empty()) {
ObjArrayTask task = _objarray_stack.pop();
follow_array_chunk(objArrayOop(task.obj()), task.index());
}
} while (!_marking_stack.is_empty() || !_objarray_stack.is_empty());
}
MarkSweep::FollowStackClosure MarkSweep::follow_stack_closure;
void MarkSweep::FollowStackClosure::do_void() { follow_stack(); }
template <class T> inline void MarkSweep::follow_root(T* p) {
assert(!Universe::heap()->is_in(p),
"roots shouldn't be things within the heap");
T heap_oop = RawAccess<>::oop_load(p);
if (!CompressedOops::is_null(heap_oop)) {
oop obj = CompressedOops::decode_not_null(heap_oop);
if (!obj->mark().is_marked()) {
mark_object(obj);
follow_object(obj);
}
}
follow_stack();
}
void MarkSweep::FollowRootClosure::do_oop(oop* p) { follow_root(p); }
void MarkSweep::FollowRootClosure::do_oop(narrowOop* p) { follow_root(p); }
void PreservedMark::adjust_pointer() {
MarkSweep::adjust_pointer(&_obj);
}
void PreservedMark::restore() {
_obj->set_mark(_mark);
}
// We preserve the mark which should be replaced at the end and the location
// that it will go. Note that the object that this markWord belongs to isn't
// currently at that address but it will be after phase4
void MarkSweep::preserve_mark(oop obj, markWord mark) {
// We try to store preserved marks in the to space of the new generation since
// this is storage which should be available. Most of the time this should be
// sufficient space for the marks we need to preserve but if it isn't we fall
// back to using Stacks to keep track of the overflow.
if (_preserved_count < _preserved_count_max) {
_preserved_marks[_preserved_count++] = PreservedMark(obj, mark);
} else {
_preserved_overflow_stack.push(PreservedMark(obj, mark));
}
}
void MarkSweep::set_ref_processor(ReferenceProcessor* rp) {
_ref_processor = rp;
mark_and_push_closure.set_ref_discoverer(_ref_processor);
}
AdjustPointerClosure MarkSweep::adjust_pointer_closure;
void MarkSweep::adjust_marks() {
// adjust the oops we saved earlier
for (size_t i = 0; i < _preserved_count; i++) {
_preserved_marks[i].adjust_pointer();
}
// deal with the overflow stack
StackIterator<PreservedMark, mtGC> iter(_preserved_overflow_stack);
while (!iter.is_empty()) {
PreservedMark* p = iter.next_addr();
p->adjust_pointer();
}
}
void MarkSweep::restore_marks() {
log_trace(gc)("Restoring " SIZE_FORMAT " marks", _preserved_count + _preserved_overflow_stack.size());
// restore the marks we saved earlier
for (size_t i = 0; i < _preserved_count; i++) {
_preserved_marks[i].restore();
}
// deal with the overflow
while (!_preserved_overflow_stack.is_empty()) {
PreservedMark p = _preserved_overflow_stack.pop();
p.restore();
}
}
MarkSweep::IsAliveClosure MarkSweep::is_alive;
bool MarkSweep::IsAliveClosure::do_object_b(oop p) { return p->is_gc_marked(); }
MarkSweep::KeepAliveClosure MarkSweep::keep_alive;
void MarkSweep::KeepAliveClosure::do_oop(oop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); }
void MarkSweep::KeepAliveClosure::do_oop(narrowOop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); }
void MarkSweep::initialize() {
MarkSweep::_gc_timer = new STWGCTimer();
MarkSweep::_gc_tracer = new SerialOldTracer();
MarkSweep::_string_dedup_requests = new StringDedup::Requests();
}
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