8025852: Remove unnecessary setters in collector policy classes
Summary: Use instance variables directly within the collector policy classes and remove unused setters.
Reviewed-by: tschatzl, jcoomes
/*
* Copyright (c) 2001, 2012, 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/g1CollectedHeap.inline.hpp"
#include "gc_implementation/g1/satbQueue.hpp"
#include "memory/allocation.inline.hpp"
#include "memory/sharedHeap.hpp"
#include "oops/oop.inline.hpp"
#include "runtime/mutexLocker.hpp"
#include "runtime/thread.hpp"
#include "runtime/vmThread.hpp"
void ObjPtrQueue::flush() {
// The buffer might contain refs into the CSet. We have to filter it
// first before we flush it, otherwise we might end up with an
// enqueued buffer with refs into the CSet which breaks our invariants.
filter();
PtrQueue::flush();
}
// This method removes entries from an SATB buffer that will not be
// useful to the concurrent marking threads. An entry is removed if it
// satisfies one of the following conditions:
//
// * it points to an object outside the G1 heap (G1's concurrent
// marking only visits objects inside the G1 heap),
// * it points to an object that has been allocated since marking
// started (according to SATB those objects do not need to be
// visited during marking), or
// * it points to an object that has already been marked (no need to
// process it again).
//
// The rest of the entries will be retained and are compacted towards
// the top of the buffer. Note that, because we do not allow old
// regions in the CSet during marking, all objects on the CSet regions
// are young (eden or survivors) and therefore implicitly live. So any
// references into the CSet will be removed during filtering.
void ObjPtrQueue::filter() {
G1CollectedHeap* g1h = G1CollectedHeap::heap();
void** buf = _buf;
size_t sz = _sz;
if (buf == NULL) {
// nothing to do
return;
}
// Used for sanity checking at the end of the loop.
debug_only(size_t entries = 0; size_t retained = 0;)
size_t i = sz;
size_t new_index = sz;
while (i > _index) {
assert(i > 0, "we should have at least one more entry to process");
i -= oopSize;
debug_only(entries += 1;)
oop* p = (oop*) &buf[byte_index_to_index((int) i)];
oop obj = *p;
// NULL the entry so that unused parts of the buffer contain NULLs
// at the end. If we are going to retain it we will copy it to its
// final place. If we have retained all entries we have visited so
// far, we'll just end up copying it to the same place.
*p = NULL;
bool retain = g1h->is_obj_ill(obj);
if (retain) {
assert(new_index > 0, "we should not have already filled up the buffer");
new_index -= oopSize;
assert(new_index >= i,
"new_index should never be below i, as we alwaysr compact 'up'");
oop* new_p = (oop*) &buf[byte_index_to_index((int) new_index)];
assert(new_p >= p, "the destination location should never be below "
"the source as we always compact 'up'");
assert(*new_p == NULL,
"we should have already cleared the destination location");
*new_p = obj;
debug_only(retained += 1;)
}
}
#ifdef ASSERT
size_t entries_calc = (sz - _index) / oopSize;
assert(entries == entries_calc, "the number of entries we counted "
"should match the number of entries we calculated");
size_t retained_calc = (sz - new_index) / oopSize;
assert(retained == retained_calc, "the number of retained entries we counted "
"should match the number of retained entries we calculated");
#endif // ASSERT
_index = new_index;
}
// This method will first apply the above filtering to the buffer. If
// post-filtering a large enough chunk of the buffer has been cleared
// we can re-use the buffer (instead of enqueueing it) and we can just
// allow the mutator to carry on executing using the same buffer
// instead of replacing it.
bool ObjPtrQueue::should_enqueue_buffer() {
assert(_lock == NULL || _lock->owned_by_self(),
"we should have taken the lock before calling this");
// Even if G1SATBBufferEnqueueingThresholdPercent == 0 we have to
// filter the buffer given that this will remove any references into
// the CSet as we currently assume that no such refs will appear in
// enqueued buffers.
// This method should only be called if there is a non-NULL buffer
// that is full.
assert(_index == 0, "pre-condition");
assert(_buf != NULL, "pre-condition");
filter();
size_t sz = _sz;
size_t all_entries = sz / oopSize;
size_t retained_entries = (sz - _index) / oopSize;
size_t perc = retained_entries * 100 / all_entries;
bool should_enqueue = perc > (size_t) G1SATBBufferEnqueueingThresholdPercent;
return should_enqueue;
}
void ObjPtrQueue::apply_closure(ObjectClosure* cl) {
if (_buf != NULL) {
apply_closure_to_buffer(cl, _buf, _index, _sz);
}
}
void ObjPtrQueue::apply_closure_and_empty(ObjectClosure* cl) {
if (_buf != NULL) {
apply_closure_to_buffer(cl, _buf, _index, _sz);
_index = _sz;
}
}
void ObjPtrQueue::apply_closure_to_buffer(ObjectClosure* cl,
void** buf, size_t index, size_t sz) {
if (cl == NULL) return;
for (size_t i = index; i < sz; i += oopSize) {
oop obj = (oop)buf[byte_index_to_index((int)i)];
// There can be NULL entries because of destructors.
if (obj != NULL) {
cl->do_object(obj);
}
}
}
#ifndef PRODUCT
// Helpful for debugging
void ObjPtrQueue::print(const char* name) {
print(name, _buf, _index, _sz);
}
void ObjPtrQueue::print(const char* name,
void** buf, size_t index, size_t sz) {
gclog_or_tty->print_cr(" SATB BUFFER [%s] buf: "PTR_FORMAT" "
"index: "SIZE_FORMAT" sz: "SIZE_FORMAT,
name, buf, index, sz);
}
#endif // PRODUCT
#ifdef ASSERT
void ObjPtrQueue::verify_oops_in_buffer() {
if (_buf == NULL) return;
for (size_t i = _index; i < _sz; i += oopSize) {
oop obj = (oop)_buf[byte_index_to_index((int)i)];
assert(obj != NULL && obj->is_oop(true /* ignore mark word */),
"Not an oop");
}
}
#endif
#ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
#pragma warning( disable:4355 ) // 'this' : used in base member initializer list
#endif // _MSC_VER
SATBMarkQueueSet::SATBMarkQueueSet() :
PtrQueueSet(), _closure(NULL), _par_closures(NULL),
_shared_satb_queue(this, true /*perm*/) { }
void SATBMarkQueueSet::initialize(Monitor* cbl_mon, Mutex* fl_lock,
int process_completed_threshold,
Mutex* lock) {
PtrQueueSet::initialize(cbl_mon, fl_lock, process_completed_threshold, -1);
_shared_satb_queue.set_lock(lock);
if (ParallelGCThreads > 0) {
_par_closures = NEW_C_HEAP_ARRAY(ObjectClosure*, ParallelGCThreads, mtGC);
}
}
void SATBMarkQueueSet::handle_zero_index_for_thread(JavaThread* t) {
DEBUG_ONLY(t->satb_mark_queue().verify_oops_in_buffer();)
t->satb_mark_queue().handle_zero_index();
}
#ifdef ASSERT
void SATBMarkQueueSet::dump_active_values(JavaThread* first,
bool expected_active) {
gclog_or_tty->print_cr("SATB queue active values for Java Threads");
gclog_or_tty->print_cr(" SATB queue set: active is %s",
(is_active()) ? "TRUE" : "FALSE");
gclog_or_tty->print_cr(" expected_active is %s",
(expected_active) ? "TRUE" : "FALSE");
for (JavaThread* t = first; t; t = t->next()) {
bool active = t->satb_mark_queue().is_active();
gclog_or_tty->print_cr(" thread %s, active is %s",
t->name(), (active) ? "TRUE" : "FALSE");
}
}
#endif // ASSERT
void SATBMarkQueueSet::set_active_all_threads(bool b,
bool expected_active) {
assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
JavaThread* first = Threads::first();
#ifdef ASSERT
if (_all_active != expected_active) {
dump_active_values(first, expected_active);
// I leave this here as a guarantee, instead of an assert, so
// that it will still be compiled in if we choose to uncomment
// the #ifdef ASSERT in a product build. The whole block is
// within an #ifdef ASSERT so the guarantee will not be compiled
// in a product build anyway.
guarantee(false,
"SATB queue set has an unexpected active value");
}
#endif // ASSERT
_all_active = b;
for (JavaThread* t = first; t; t = t->next()) {
#ifdef ASSERT
bool active = t->satb_mark_queue().is_active();
if (active != expected_active) {
dump_active_values(first, expected_active);
// I leave this here as a guarantee, instead of an assert, so
// that it will still be compiled in if we choose to uncomment
// the #ifdef ASSERT in a product build. The whole block is
// within an #ifdef ASSERT so the guarantee will not be compiled
// in a product build anyway.
guarantee(false,
"thread has an unexpected active value in its SATB queue");
}
#endif // ASSERT
t->satb_mark_queue().set_active(b);
}
}
void SATBMarkQueueSet::filter_thread_buffers() {
for(JavaThread* t = Threads::first(); t; t = t->next()) {
t->satb_mark_queue().filter();
}
shared_satb_queue()->filter();
}
void SATBMarkQueueSet::set_closure(ObjectClosure* closure) {
_closure = closure;
}
void SATBMarkQueueSet::set_par_closure(int i, ObjectClosure* par_closure) {
assert(ParallelGCThreads > 0 && _par_closures != NULL, "Precondition");
_par_closures[i] = par_closure;
}
void SATBMarkQueueSet::iterate_closure_all_threads() {
for(JavaThread* t = Threads::first(); t; t = t->next()) {
t->satb_mark_queue().apply_closure_and_empty(_closure);
}
shared_satb_queue()->apply_closure_and_empty(_closure);
}
void SATBMarkQueueSet::par_iterate_closure_all_threads(int worker) {
SharedHeap* sh = SharedHeap::heap();
int parity = sh->strong_roots_parity();
for(JavaThread* t = Threads::first(); t; t = t->next()) {
if (t->claim_oops_do(true, parity)) {
t->satb_mark_queue().apply_closure_and_empty(_par_closures[worker]);
}
}
// We also need to claim the VMThread so that its parity is updated
// otherwise the next call to Thread::possibly_parallel_oops_do inside
// a StrongRootsScope might skip the VMThread because it has a stale
// parity that matches the parity set by the StrongRootsScope
//
// Whichever worker succeeds in claiming the VMThread gets to do
// the shared queue.
VMThread* vmt = VMThread::vm_thread();
if (vmt->claim_oops_do(true, parity)) {
shared_satb_queue()->apply_closure_and_empty(_par_closures[worker]);
}
}
bool SATBMarkQueueSet::apply_closure_to_completed_buffer_work(bool par,
int worker) {
BufferNode* nd = NULL;
{
MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
if (_completed_buffers_head != NULL) {
nd = _completed_buffers_head;
_completed_buffers_head = nd->next();
if (_completed_buffers_head == NULL) _completed_buffers_tail = NULL;
_n_completed_buffers--;
if (_n_completed_buffers == 0) _process_completed = false;
}
}
ObjectClosure* cl = (par ? _par_closures[worker] : _closure);
if (nd != NULL) {
void **buf = BufferNode::make_buffer_from_node(nd);
ObjPtrQueue::apply_closure_to_buffer(cl, buf, 0, _sz);
deallocate_buffer(buf);
return true;
} else {
return false;
}
}
void SATBMarkQueueSet::iterate_completed_buffers_read_only(ObjectClosure* cl) {
assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
assert(cl != NULL, "pre-condition");
BufferNode* nd = _completed_buffers_head;
while (nd != NULL) {
void** buf = BufferNode::make_buffer_from_node(nd);
ObjPtrQueue::apply_closure_to_buffer(cl, buf, 0, _sz);
nd = nd->next();
}
}
void SATBMarkQueueSet::iterate_thread_buffers_read_only(ObjectClosure* cl) {
assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
assert(cl != NULL, "pre-condition");
for (JavaThread* t = Threads::first(); t; t = t->next()) {
t->satb_mark_queue().apply_closure(cl);
}
shared_satb_queue()->apply_closure(cl);
}
#ifndef PRODUCT
// Helpful for debugging
#define SATB_PRINTER_BUFFER_SIZE 256
void SATBMarkQueueSet::print_all(const char* msg) {
char buffer[SATB_PRINTER_BUFFER_SIZE];
assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
gclog_or_tty->cr();
gclog_or_tty->print_cr("SATB BUFFERS [%s]", msg);
BufferNode* nd = _completed_buffers_head;
int i = 0;
while (nd != NULL) {
void** buf = BufferNode::make_buffer_from_node(nd);
jio_snprintf(buffer, SATB_PRINTER_BUFFER_SIZE, "Enqueued: %d", i);
ObjPtrQueue::print(buffer, buf, 0, _sz);
nd = nd->next();
i += 1;
}
for (JavaThread* t = Threads::first(); t; t = t->next()) {
jio_snprintf(buffer, SATB_PRINTER_BUFFER_SIZE, "Thread: %s", t->name());
t->satb_mark_queue().print(buffer);
}
shared_satb_queue()->print("Shared");
gclog_or_tty->cr();
}
#endif // PRODUCT
void SATBMarkQueueSet::abandon_partial_marking() {
BufferNode* buffers_to_delete = NULL;
{
MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
while (_completed_buffers_head != NULL) {
BufferNode* nd = _completed_buffers_head;
_completed_buffers_head = nd->next();
nd->set_next(buffers_to_delete);
buffers_to_delete = nd;
}
_completed_buffers_tail = NULL;
_n_completed_buffers = 0;
DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked());
}
while (buffers_to_delete != NULL) {
BufferNode* nd = buffers_to_delete;
buffers_to_delete = nd->next();
deallocate_buffer(BufferNode::make_buffer_from_node(nd));
}
assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
// So we can safely manipulate these queues.
for (JavaThread* t = Threads::first(); t; t = t->next()) {
t->satb_mark_queue().reset();
}
shared_satb_queue()->reset();
}