8131645: [ARM64] crash on Cavium when using G1
Summary: Add a fence when creating the CodeRootSetTable so the readers do not see invalid memory.
Reviewed-by: aph, tschatzl
/*
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* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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#include "precompiled.hpp"
#include "gc/g1/g1CollectedHeap.inline.hpp"
#include "gc/g1/g1SATBCardTableModRefBS.hpp"
#include "gc/g1/heapRegion.hpp"
#include "gc/g1/satbQueue.hpp"
#include "gc/shared/memset_with_concurrent_readers.hpp"
#include "oops/oop.inline.hpp"
#include "runtime/atomic.inline.hpp"
#include "runtime/mutexLocker.hpp"
#include "runtime/orderAccess.inline.hpp"
#include "runtime/thread.inline.hpp"
G1SATBCardTableModRefBS::G1SATBCardTableModRefBS(
MemRegion whole_heap,
const BarrierSet::FakeRtti& fake_rtti) :
CardTableModRefBS(whole_heap, fake_rtti.add_tag(BarrierSet::G1SATBCT))
{ }
void G1SATBCardTableModRefBS::enqueue(oop pre_val) {
// Nulls should have been already filtered.
assert(pre_val->is_oop(true), "Error");
if (!JavaThread::satb_mark_queue_set().is_active()) return;
Thread* thr = Thread::current();
if (thr->is_Java_thread()) {
JavaThread* jt = (JavaThread*)thr;
jt->satb_mark_queue().enqueue(pre_val);
} else {
MutexLockerEx x(Shared_SATB_Q_lock, Mutex::_no_safepoint_check_flag);
JavaThread::satb_mark_queue_set().shared_satb_queue()->enqueue(pre_val);
}
}
template <class T> void
G1SATBCardTableModRefBS::write_ref_array_pre_work(T* dst, int count) {
if (!JavaThread::satb_mark_queue_set().is_active()) return;
T* elem_ptr = dst;
for (int i = 0; i < count; i++, elem_ptr++) {
T heap_oop = oopDesc::load_heap_oop(elem_ptr);
if (!oopDesc::is_null(heap_oop)) {
enqueue(oopDesc::decode_heap_oop_not_null(heap_oop));
}
}
}
void G1SATBCardTableModRefBS::write_ref_array_pre(oop* dst, int count, bool dest_uninitialized) {
if (!dest_uninitialized) {
write_ref_array_pre_work(dst, count);
}
}
void G1SATBCardTableModRefBS::write_ref_array_pre(narrowOop* dst, int count, bool dest_uninitialized) {
if (!dest_uninitialized) {
write_ref_array_pre_work(dst, count);
}
}
bool G1SATBCardTableModRefBS::mark_card_deferred(size_t card_index) {
jbyte val = _byte_map[card_index];
// It's already processed
if ((val & (clean_card_mask_val() | deferred_card_val())) == deferred_card_val()) {
return false;
}
if (val == g1_young_gen) {
// the card is for a young gen region. We don't need to keep track of all pointers into young
return false;
}
// Cached bit can be installed either on a clean card or on a claimed card.
jbyte new_val = val;
if (val == clean_card_val()) {
new_val = (jbyte)deferred_card_val();
} else {
if (val & claimed_card_val()) {
new_val = val | (jbyte)deferred_card_val();
}
}
if (new_val != val) {
Atomic::cmpxchg(new_val, &_byte_map[card_index], val);
}
return true;
}
void G1SATBCardTableModRefBS::g1_mark_as_young(const MemRegion& mr) {
jbyte *const first = byte_for(mr.start());
jbyte *const last = byte_after(mr.last());
memset_with_concurrent_readers(first, g1_young_gen, last - first);
}
#ifndef PRODUCT
void G1SATBCardTableModRefBS::verify_g1_young_region(MemRegion mr) {
verify_region(mr, g1_young_gen, true);
}
#endif
void G1SATBCardTableLoggingModRefBSChangedListener::on_commit(uint start_idx, size_t num_regions, bool zero_filled) {
// Default value for a clean card on the card table is -1. So we cannot take advantage of the zero_filled parameter.
MemRegion mr(G1CollectedHeap::heap()->bottom_addr_for_region(start_idx), num_regions * HeapRegion::GrainWords);
_card_table->clear(mr);
}
G1SATBCardTableLoggingModRefBS::
G1SATBCardTableLoggingModRefBS(MemRegion whole_heap) :
G1SATBCardTableModRefBS(whole_heap, BarrierSet::FakeRtti(G1SATBCTLogging)),
_dcqs(JavaThread::dirty_card_queue_set()),
_listener()
{
_listener.set_card_table(this);
}
void G1SATBCardTableLoggingModRefBS::initialize(G1RegionToSpaceMapper* mapper) {
mapper->set_mapping_changed_listener(&_listener);
_byte_map_size = mapper->reserved().byte_size();
_guard_index = cards_required(_whole_heap.word_size()) - 1;
_last_valid_index = _guard_index - 1;
HeapWord* low_bound = _whole_heap.start();
HeapWord* high_bound = _whole_heap.end();
_cur_covered_regions = 1;
_covered[0] = _whole_heap;
_byte_map = (jbyte*) mapper->reserved().start();
byte_map_base = _byte_map - (uintptr_t(low_bound) >> card_shift);
assert(byte_for(low_bound) == &_byte_map[0], "Checking start of map");
assert(byte_for(high_bound-1) <= &_byte_map[_last_valid_index], "Checking end of map");
if (TraceCardTableModRefBS) {
gclog_or_tty->print_cr("G1SATBCardTableModRefBS::G1SATBCardTableModRefBS: ");
gclog_or_tty->print_cr(" "
" &_byte_map[0]: " INTPTR_FORMAT
" &_byte_map[_last_valid_index]: " INTPTR_FORMAT,
p2i(&_byte_map[0]),
p2i(&_byte_map[_last_valid_index]));
gclog_or_tty->print_cr(" "
" byte_map_base: " INTPTR_FORMAT,
p2i(byte_map_base));
}
}
void
G1SATBCardTableLoggingModRefBS::write_ref_field_work(void* field,
oop new_val,
bool release) {
volatile jbyte* byte = byte_for(field);
if (*byte == g1_young_gen) {
return;
}
OrderAccess::storeload();
if (*byte != dirty_card) {
*byte = dirty_card;
Thread* thr = Thread::current();
if (thr->is_Java_thread()) {
JavaThread* jt = (JavaThread*)thr;
jt->dirty_card_queue().enqueue(byte);
} else {
MutexLockerEx x(Shared_DirtyCardQ_lock,
Mutex::_no_safepoint_check_flag);
_dcqs.shared_dirty_card_queue()->enqueue(byte);
}
}
}
void
G1SATBCardTableLoggingModRefBS::write_ref_field_static(void* field,
oop new_val) {
uintptr_t field_uint = (uintptr_t)field;
uintptr_t new_val_uint = cast_from_oop<uintptr_t>(new_val);
uintptr_t comb = field_uint ^ new_val_uint;
comb = comb >> HeapRegion::LogOfHRGrainBytes;
if (comb == 0) return;
if (new_val == NULL) return;
// Otherwise, log it.
G1SATBCardTableLoggingModRefBS* g1_bs =
barrier_set_cast<G1SATBCardTableLoggingModRefBS>(G1CollectedHeap::heap()->barrier_set());
g1_bs->write_ref_field_work(field, new_val, false);
}
void
G1SATBCardTableLoggingModRefBS::invalidate(MemRegion mr, bool whole_heap) {
volatile jbyte* byte = byte_for(mr.start());
jbyte* last_byte = byte_for(mr.last());
Thread* thr = Thread::current();
if (whole_heap) {
while (byte <= last_byte) {
*byte = dirty_card;
byte++;
}
} else {
// skip all consecutive young cards
for (; byte <= last_byte && *byte == g1_young_gen; byte++);
if (byte <= last_byte) {
OrderAccess::storeload();
// Enqueue if necessary.
if (thr->is_Java_thread()) {
JavaThread* jt = (JavaThread*)thr;
for (; byte <= last_byte; byte++) {
if (*byte == g1_young_gen) {
continue;
}
if (*byte != dirty_card) {
*byte = dirty_card;
jt->dirty_card_queue().enqueue(byte);
}
}
} else {
MutexLockerEx x(Shared_DirtyCardQ_lock,
Mutex::_no_safepoint_check_flag);
for (; byte <= last_byte; byte++) {
if (*byte == g1_young_gen) {
continue;
}
if (*byte != dirty_card) {
*byte = dirty_card;
_dcqs.shared_dirty_card_queue()->enqueue(byte);
}
}
}
}
}
}