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8328508: Unify the signatures of the methods address_for_index() and index_for() in BOT implementations

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Reviewed-by: ayang, tschatzl
This commit is contained in:
Guoxiong Li 2024-03-26 13:11:28 +00:00
parent cc1800fa4d
commit 472fcb6e6e
10 changed files with 133 additions and 180 deletions
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95
src/hotspot/share/gc/g1/g1BlockOffsetTable.cpp
View File

@ -36,11 +36,11 @@
//////////////////////////////////////////////////////////////////////
G1BlockOffsetTable::G1BlockOffsetTable(MemRegion heap, G1RegionToSpaceMapper* storage) :
_reserved(heap), _offset_array(nullptr) {
_reserved(heap), _offset_base(nullptr) {
MemRegion bot_reserved = storage->reserved();
_offset_array = (u_char*)bot_reserved.start();
_offset_base = ((u_char*)bot_reserved.start() - (uintptr_t(_reserved.start()) >> CardTable::card_shift()));
log_trace(gc, bot)("G1BlockOffsetTable::G1BlockOffsetTable: ");
log_trace(gc, bot)(" rs.base(): " PTR_FORMAT " rs.size(): " SIZE_FORMAT " rs end(): " PTR_FORMAT,
@ -48,16 +48,17 @@ G1BlockOffsetTable::G1BlockOffsetTable(MemRegion heap, G1RegionToSpaceMapper* st
}
#ifdef ASSERT
void G1BlockOffsetTable::check_index(size_t index, const char* msg) const {
assert((index) < (_reserved.word_size() >> CardTable::card_shift_in_words()),
"%s - index: " SIZE_FORMAT ", _vs.committed_size: " SIZE_FORMAT,
msg, (index), (_reserved.word_size() >> CardTable::card_shift_in_words()));
assert(G1CollectedHeap::heap()->is_in(address_for_index_raw(index)),
"Index " SIZE_FORMAT " corresponding to " PTR_FORMAT
void G1BlockOffsetTable::check_address(u_char* addr, const char* msg) const {
u_char* start_addr = const_cast<u_char *>(_offset_base + (uintptr_t(_reserved.start()) >> CardTable::card_shift()));
u_char* end_addr = const_cast<u_char *>(_offset_base + (uintptr_t(_reserved.end()) >> CardTable::card_shift()));
assert(addr >= start_addr && addr <= end_addr,
"%s - offset address: " PTR_FORMAT ", start address: " PTR_FORMAT ", end address: " PTR_FORMAT,
msg, (p2i(addr)), (p2i(start_addr)), (p2i(end_addr)));
assert(G1CollectedHeap::heap()->is_in(addr_for_entry(addr)),
"Offset address " PTR_FORMAT " corresponding to " PTR_FORMAT
" (%u) is not in committed area.",
(index),
p2i(address_for_index_raw(index)),
G1CollectedHeap::heap()->addr_to_region(address_for_index_raw(index)));
(p2i(addr)), p2i(addr_for_entry(addr)),
G1CollectedHeap::heap()->addr_to_region(addr_for_entry(addr)));
}
#endif // ASSERT
@ -67,9 +68,7 @@ void G1BlockOffsetTable::check_index(size_t index, const char* msg) const {
G1BlockOffsetTablePart::G1BlockOffsetTablePart(G1BlockOffsetTable* array, HeapRegion* hr) :
_bot(array),
_hr(hr)
{
}
_hr(hr) {}
// Write the backskip value for each region.
//
@ -96,7 +95,6 @@ G1BlockOffsetTablePart::G1BlockOffsetTablePart(G1BlockOffsetTable* array, HeapRe
// the index of the entry
//
// Given an address,
// Find the index for the address
// Find the block offset table entry
// Convert the entry to a back slide
// (e.g., with today's, offset = 0x81 =>
@ -104,18 +102,18 @@ G1BlockOffsetTablePart::G1BlockOffsetTablePart(G1BlockOffsetTable* array, HeapRe
// Move back N (e.g., 8) entries and repeat with the
// value of the new entry
//
void G1BlockOffsetTablePart::set_remainder_to_point_to_start_incl(size_t start_card, size_t end_card) {
void G1BlockOffsetTablePart::set_remainder_to_point_to_start_incl(u_char* start_card, u_char* end_card) {
assert(start_card <= end_card, "precondition");
assert(start_card > _bot->index_for(_hr->bottom()), "Cannot be first card");
assert(start_card > _bot->entry_for_addr(_hr->bottom()), "Cannot be first card");
assert(_bot->offset_array(start_card-1) < CardTable::card_size_in_words(),
"Offset card has an unexpected value");
size_t start_card_for_region = start_card;
u_char* start_card_for_region = start_card;
u_char offset = max_jubyte;
for (uint i = 0; i < BOTConstants::N_powers; i++) {
// -1 so that the card with the actual offset is counted. Another -1
// so that the reach ends in this region and not at the start
// of the next.
size_t reach = start_card - 1 + (BOTConstants::power_to_cards_back(i+1) - 1);
u_char* reach = start_card - 1 + (BOTConstants::power_to_cards_back(i+1) - 1);
offset = CardTable::card_size_in_words() + i;
if (reach >= end_card) {
_bot->set_offset_array(start_card_for_region, end_card, offset);
@ -133,15 +131,14 @@ void G1BlockOffsetTablePart::set_remainder_to_point_to_start_incl(size_t start_c
// The card-interval [start_card, end_card] is a closed interval; this
// is an expensive check -- use with care and only under protection of
// suitable flag.
void G1BlockOffsetTablePart::check_all_cards(size_t start_card, size_t end_card) const {
void G1BlockOffsetTablePart::check_all_cards(u_char* start_card, u_char* end_card) const {
if (end_card < start_card) {
return;
}
guarantee(_bot->offset_array(start_card) == CardTable::card_size_in_words(), "Wrong value in second card");
for (size_t c = start_card + 1; c <= end_card; c++ /* yeah! */) {
for (u_char* c = start_card + 1; c <= end_card; c++ /* yeah! */) {
u_char entry = _bot->offset_array(c);
if (c - start_card > BOTConstants::power_to_cards_back(1)) {
if ((unsigned)(c - start_card) > BOTConstants::power_to_cards_back(1)) {
guarantee(entry > CardTable::card_size_in_words(),
"Should be in logarithmic region - "
"entry: %u, "
@ -150,7 +147,7 @@ void G1BlockOffsetTablePart::check_all_cards(size_t start_card, size_t end_card)
(uint)entry, (uint)_bot->offset_array(c), CardTable::card_size_in_words());
}
size_t backskip = BOTConstants::entry_to_cards_back(entry);
size_t landing_card = c - backskip;
u_char* landing_card = c - backskip;
guarantee(landing_card >= (start_card - 1), "Inv");
if (landing_card >= start_card) {
guarantee(_bot->offset_array(landing_card) <= entry,
@ -182,7 +179,7 @@ void G1BlockOffsetTablePart::check_all_cards(size_t start_card, size_t end_card)
void G1BlockOffsetTablePart::update_for_block_work(HeapWord* blk_start,
HeapWord* blk_end) {
HeapWord* const cur_card_boundary = align_up_by_card_size(blk_start);
size_t const index = _bot->index_for_raw(cur_card_boundary);
u_char* const offset_card = _bot->entry_for_addr(cur_card_boundary);
assert(blk_start != nullptr && blk_end > blk_start,
"phantom block");
@ -194,41 +191,41 @@ void G1BlockOffsetTablePart::update_for_block_work(HeapWord* blk_start,
"reference must be into the heap");
assert(G1CollectedHeap::heap()->is_in_reserved(blk_end - 1),
"limit must be within the heap");
assert(cur_card_boundary == _bot->_reserved.start() + index * CardTable::card_size_in_words(),
"index must agree with cur_card_boundary");
assert(cur_card_boundary == _bot->addr_for_entry(offset_card),
"Block offset table entry must agree with cur_card_boundary");
// Mark the card that holds the offset into the block.
_bot->set_offset_array(index, cur_card_boundary, blk_start);
_bot->set_offset_array(offset_card, cur_card_boundary, blk_start);
// We need to now mark the subsequent cards that this block spans.
// Index of card on which the block ends.
size_t end_index = _bot->index_for(blk_end - 1);
u_char* end_card = _bot->entry_for_addr(blk_end - 1);
// Are there more cards left to be updated?
if (index + 1 <= end_index) {
set_remainder_to_point_to_start_incl(index + 1, end_index);
if (offset_card + 1 <= end_card) {
set_remainder_to_point_to_start_incl(offset_card + 1, end_card);
}
#ifdef ASSERT
// Calculate new_card_boundary this way because end_index
// may be the last valid index in the covered region.
HeapWord* new_card_boundary = _bot->address_for_index(end_index) + CardTable::card_size_in_words();
HeapWord* new_card_boundary = _bot->addr_for_entry(end_card) + CardTable::card_size_in_words();
assert(new_card_boundary >= blk_end, "postcondition");
// The offset can be 0 if the block starts on a boundary. That
// is checked by an assertion above.
size_t start_index = _bot->index_for(blk_start);
HeapWord* boundary = _bot->address_for_index(start_index);
assert((_bot->offset_array(index) == 0 && blk_start == boundary) ||
(_bot->offset_array(index) > 0 && _bot->offset_array(index) < CardTable::card_size_in_words()),
u_char* previous_card = _bot->entry_for_addr(blk_start);
HeapWord* boundary = _bot->addr_for_entry(previous_card);
assert((_bot->offset_array(offset_card) == 0 && blk_start == boundary) ||
(_bot->offset_array(offset_card) > 0 && _bot->offset_array(offset_card) < CardTable::card_size_in_words()),
"offset array should have been set - "
"index offset: %u, "
"blk_start: " PTR_FORMAT ", "
"boundary: " PTR_FORMAT,
(uint)_bot->offset_array(index),
(uint)_bot->offset_array(offset_card),
p2i(blk_start), p2i(boundary));
for (size_t j = index + 1; j <= end_index; j++) {
for (u_char* j = offset_card + 1; j <= end_card; j++) {
assert(_bot->offset_array(j) > 0 &&
_bot->offset_array(j) <=
(u_char) (CardTable::card_size_in_words() + BOTConstants::N_powers - 1),
@ -243,16 +240,16 @@ void G1BlockOffsetTablePart::update_for_block_work(HeapWord* blk_start,
void G1BlockOffsetTablePart::verify() const {
assert(_hr->bottom() < _hr->top(), "Only non-empty regions should be verified.");
size_t start_card = _bot->index_for(_hr->bottom());
size_t end_card = _bot->index_for(_hr->top() - 1);
u_char* start_card = _bot->entry_for_addr(_hr->bottom());
u_char* end_card = _bot->entry_for_addr(_hr->top() - 1);
for (size_t current_card = start_card; current_card < end_card; current_card++) {
for (u_char* current_card = start_card; current_card < end_card; current_card++) {
u_char entry = _bot->offset_array(current_card);
if (entry < CardTable::card_size_in_words()) {
// The entry should point to an object before the current card. Verify that
// it is possible to walk from that object in to the current card by just
// iterating over the objects following it.
HeapWord* card_address = _bot->address_for_index(current_card);
HeapWord* card_address = _bot->addr_for_entry(current_card);
HeapWord* obj_end = card_address - entry;
while (obj_end < card_address) {
HeapWord* obj = obj_end;
@ -272,9 +269,9 @@ void G1BlockOffsetTablePart::verify() const {
size_t max_backskip = current_card - start_card;
guarantee(backskip <= max_backskip,
"Going backwards beyond the start_card. start_card: " SIZE_FORMAT " current_card: " SIZE_FORMAT " backskip: " SIZE_FORMAT,
start_card, current_card, backskip);
p2i(start_card), p2i(current_card), backskip);
HeapWord* backskip_address = _bot->address_for_index(current_card - backskip);
HeapWord* backskip_address = _bot->addr_for_entry(current_card - backskip);
guarantee(backskip_address >= _hr->bottom(),
"Going backwards beyond bottom of the region: bottom: " PTR_FORMAT ", backskip_address: " PTR_FORMAT,
p2i(_hr->bottom()), p2i(backskip_address));
@ -284,14 +281,14 @@ void G1BlockOffsetTablePart::verify() const {
#ifndef PRODUCT
void G1BlockOffsetTablePart::print_on(outputStream* out) {
size_t from_index = _bot->index_for(_hr->bottom());
size_t to_index = _bot->index_for(_hr->end());
u_char* from_card = _bot->entry_for_addr(_hr->bottom());
u_char* to_card = _bot->entry_for_addr(_hr->end());
out->print_cr(">> BOT for area [" PTR_FORMAT "," PTR_FORMAT ") "
"cards [" SIZE_FORMAT "," SIZE_FORMAT ")",
p2i(_hr->bottom()), p2i(_hr->end()), from_index, to_index);
for (size_t i = from_index; i < to_index; ++i) {
p2i(_hr->bottom()), p2i(_hr->end()), p2i(from_card), p2i(to_card));
for (u_char* i = from_card; i < to_card; ++i) {
out->print_cr(" entry " SIZE_FORMAT_W(8) " | " PTR_FORMAT " : %3u",
i, p2i(_bot->address_for_index(i)),
p2i(i), p2i(_bot->addr_for_entry(i)),
(uint) _bot->offset_array(i));
}
}

35
src/hotspot/share/gc/g1/g1BlockOffsetTable.hpp
View File

@ -51,9 +51,8 @@ private:
// The reserved region covered by the table.
MemRegion _reserved;
// Array for keeping offsets for retrieving object start fast given an
// address.
volatile u_char* _offset_array; // byte array keeping backwards offsets
// Biased array-start of BOT array for fast BOT entry translation
volatile u_char* _offset_base;
void check_offset(size_t offset, const char* msg) const {
assert(offset < CardTable::card_size_in_words(),
@ -63,16 +62,16 @@ private:
// Bounds checking accessors:
// For performance these have to devolve to array accesses in product builds.
inline u_char offset_array(size_t index) const;
inline u_char offset_array(u_char* addr) const;
inline void set_offset_array_raw(size_t index, u_char offset);
inline void set_offset_array(size_t index, u_char offset);
inline void set_offset_array_raw(u_char* addr, u_char offset);
inline void set_offset_array(u_char* addr, u_char offset);
inline void set_offset_array(size_t index, HeapWord* high, HeapWord* low);
inline void set_offset_array(u_char* addr, HeapWord* high, HeapWord* low);
inline void set_offset_array(size_t left, size_t right, u_char offset);
inline void set_offset_array(u_char* left, u_char* right, u_char offset);
void check_index(size_t index, const char* msg) const NOT_DEBUG_RETURN;
void check_address(u_char* addr, const char* msg) const NOT_DEBUG_RETURN;
public:
@ -92,17 +91,11 @@ public:
// in the heap parameter.
G1BlockOffsetTable(MemRegion heap, G1RegionToSpaceMapper* storage);
// Return the appropriate index into "_offset_array" for "p".
inline size_t index_for(const void* p) const;
inline size_t index_for_raw(const void* p) const;
// Mapping from address to object start array entry
u_char* entry_for_addr(const void* const p) const;
// Return the address indicating the start of the region corresponding to
// "index" in "_offset_array".
inline HeapWord* address_for_index(size_t index) const;
// Variant of address_for_index that does not check the index for validity.
inline HeapWord* address_for_index_raw(size_t index) const {
return _reserved.start() + (index << CardTable::card_shift_in_words());
}
// Mapping from object start array entry to address of first word
HeapWord* addr_for_entry(const u_char* const p) const;
};
class G1BlockOffsetTablePart {
@ -117,12 +110,12 @@ private:
// Sets the entries corresponding to the cards starting at "start" and ending
// at "end" to point back to the card before "start"; [start, end]
void set_remainder_to_point_to_start_incl(size_t start, size_t end);
void set_remainder_to_point_to_start_incl(u_char* start, u_char* end);
// Update BOT entries corresponding to the mem range [blk_start, blk_end).
void update_for_block_work(HeapWord* blk_start, HeapWord* blk_end);
void check_all_cards(size_t left_card, size_t right_card) const NOT_DEBUG_RETURN;
void check_all_cards(u_char* left_card, u_char* right_card) const NOT_DEBUG_RETURN;
static HeapWord* align_up_by_card_size(HeapWord* const addr) {
return align_up(addr, CardTable::card_size());

71
src/hotspot/share/gc/g1/g1BlockOffsetTable.inline.hpp
View File

@ -38,81 +38,68 @@ inline HeapWord* G1BlockOffsetTablePart::block_start_reaching_into_card(const vo
#ifdef ASSERT
if (!_hr->is_continues_humongous()) {
// For non-ContinuesHumongous regions, the first obj always starts from bottom.
u_char offset = _bot->offset_array(_bot->index_for(_hr->bottom()));
u_char offset = _bot->offset_array(_bot->entry_for_addr(_hr->bottom()));
assert(offset == 0, "Found offset %u instead of 0 for region %u %s",
offset, _hr->hrm_index(), _hr->get_short_type_str());
}
#endif
size_t index = _bot->index_for(addr);
u_char offset = _bot->offset_array(index);
u_char* entry = _bot->entry_for_addr(addr);
u_char offset = _bot->offset_array(entry);
while (offset >= CardTable::card_size_in_words()) {
// The excess of the offset from N_words indicates a power of Base
// to go back by.
size_t n_cards_back = BOTConstants::entry_to_cards_back(offset);
index -= n_cards_back;
offset = _bot->offset_array(index);
entry -= n_cards_back;
offset = _bot->offset_array(entry);
}
assert(offset < CardTable::card_size_in_words(), "offset too large");
HeapWord* q = _bot->address_for_index(index);
HeapWord* q = _bot->addr_for_entry(entry);
return q - offset;
}
u_char G1BlockOffsetTable::offset_array(size_t index) const {
check_index(index, "index out of range");
return Atomic::load(&_offset_array[index]);
u_char G1BlockOffsetTable::offset_array(u_char* addr) const {
check_address(addr, "Block offset table address out of range");
return Atomic::load(addr);
}
void G1BlockOffsetTable::set_offset_array_raw(size_t index, u_char offset) {
Atomic::store(&_offset_array[index], offset);
void G1BlockOffsetTable::set_offset_array_raw(u_char* addr, u_char offset) {
Atomic::store(addr, offset);
}
void G1BlockOffsetTable::set_offset_array(size_t index, u_char offset) {
check_index(index, "index out of range");
set_offset_array_raw(index, offset);
void G1BlockOffsetTable::set_offset_array(u_char* addr, u_char offset) {
check_address(addr, "Block offset table address out of range");
set_offset_array_raw(addr, offset);
}
void G1BlockOffsetTable::set_offset_array(size_t index, HeapWord* high, HeapWord* low) {
check_index(index, "index out of range");
void G1BlockOffsetTable::set_offset_array(u_char* addr, HeapWord* high, HeapWord* low) {
check_address(addr, "Block offset table address out of range");
assert(high >= low, "addresses out of order");
size_t offset = pointer_delta(high, low);
check_offset(offset, "offset too large");
set_offset_array(index, (u_char)offset);
set_offset_array(addr, (u_char)offset);
}
void G1BlockOffsetTable::set_offset_array(size_t left, size_t right, u_char offset) {
check_index(right, "right index out of range");
void G1BlockOffsetTable::set_offset_array(u_char* left, u_char* right, u_char offset) {
check_address(right, "Right block offset table address out of range");
assert(left <= right, "indexes out of order");
size_t num_cards = right - left + 1;
memset_with_concurrent_readers
(const_cast<u_char*> (&_offset_array[left]), offset, num_cards);
(const_cast<u_char*> (left), offset, num_cards);
}
// Variant of index_for that does not check the index for validity.
inline size_t G1BlockOffsetTable::index_for_raw(const void* p) const {
return pointer_delta((char*)p, _reserved.start(), sizeof(char)) >> CardTable::card_shift();
}
inline size_t G1BlockOffsetTable::index_for(const void* p) const {
char* pc = (char*)p;
assert(pc >= (char*)_reserved.start() &&
pc < (char*)_reserved.end(),
"p (" PTR_FORMAT ") not in reserved [" PTR_FORMAT ", " PTR_FORMAT ")",
p2i(p), p2i(_reserved.start()), p2i(_reserved.end()));
size_t result = index_for_raw(p);
check_index(result, "bad index from address");
inline u_char* G1BlockOffsetTable::entry_for_addr(const void* const p) const {
assert(_reserved.contains(p),
"out of bounds access to block offset table");
u_char* result = const_cast<u_char *>(&_offset_base[uintptr_t(p) >> CardTable::card_shift()]);
return result;
}
inline HeapWord* G1BlockOffsetTable::address_for_index(size_t index) const {
check_index(index, "index out of range");
HeapWord* result = address_for_index_raw(index);
assert(result >= _reserved.start() && result < _reserved.end(),
"bad address from index result " PTR_FORMAT
" _reserved.start() " PTR_FORMAT " _reserved.end() " PTR_FORMAT,
p2i(result), p2i(_reserved.start()), p2i(_reserved.end()));
inline HeapWord* G1BlockOffsetTable::addr_for_entry(const u_char* const p) const {
size_t delta = pointer_delta(p, _offset_base, sizeof(u_char));
HeapWord* result = (HeapWord*) (delta << CardTable::card_shift());
assert(_reserved.contains(result),
"out of bounds accessor from block offset table");
return result;
}

2
src/hotspot/share/gc/g1/g1RemSet.cpp
View File

@ -531,7 +531,7 @@ class G1ScanHRForRegionClosure : public HeapRegionClosure {
return;
}
HeapWord* scan_end = MIN2(card_start + (num_cards << CardTable::card_shift_in_words()), top);
HeapWord* scan_end = MIN2(card_start + (num_cards << (CardTable::card_shift() - LogHeapWordSize)), top);
if (_scanned_to >= scan_end) {
return;
}

48
src/hotspot/share/gc/serial/serialBlockOffsetTable.cpp
View File

@ -47,7 +47,7 @@ SerialBlockOffsetSharedArray::SerialBlockOffsetSharedArray(MemRegion reserved,
if (!_vs.initialize(rs, 0)) {
vm_exit_during_initialization("Could not reserve enough space for heap offset array");
}
_offset_array = (uint8_t*)_vs.low_boundary();
_offset_base = (uint8_t*)(_vs.low_boundary() - (uintptr_t(reserved.start()) >> CardTable::card_shift()));
resize(init_word_size);
log_trace(gc, bot)("SerialBlockOffsetSharedArray::SerialBlockOffsetSharedArray: ");
log_trace(gc, bot)(" rs.base(): " PTR_FORMAT " rs.size(): " SIZE_FORMAT_X_0 " rs end(): " PTR_FORMAT,
@ -102,7 +102,6 @@ void SerialBlockOffsetSharedArray::resize(size_t new_word_size) {
// the index of the entry
//
// Given an address,
// Find the index for the address
// Find the block offset table entry
// Convert the entry to a back slide
// (e.g., with today's, offset = 0x81 =>
@ -113,22 +112,22 @@ void SerialBlockOffsetSharedArray::resize(size_t new_word_size) {
void SerialBlockOffsetTable::update_for_block_work(HeapWord* blk_start,
HeapWord* blk_end) {
HeapWord* const cur_card_boundary = align_up_by_card_size(blk_start);
size_t const offset_card = _array->index_for(cur_card_boundary);
uint8_t* const offset_card = _array->entry_for_addr(cur_card_boundary);
// The first card holds the actual offset.
_array->set_offset_array(offset_card, cur_card_boundary, blk_start);
// Check if this block spans over other cards.
size_t end_card = _array->index_for(blk_end - 1);
uint8_t* end_card = _array->entry_for_addr(blk_end - 1);
assert(offset_card <= end_card, "inv");
if (offset_card != end_card) {
// Handling remaining cards.
size_t start_card_for_region = offset_card + 1;
uint8_t* start_card_for_region = offset_card + 1;
for (uint i = 0; i < BOTConstants::N_powers; i++) {
// -1 so that the reach ends in this region and not at the start
// of the next.
size_t reach = offset_card + BOTConstants::power_to_cards_back(i + 1) - 1;
uint8_t* reach = offset_card + BOTConstants::power_to_cards_back(i + 1) - 1;
uint8_t value = checked_cast<uint8_t>(CardTable::card_size_in_words() + i);
_array->set_offset_array(start_card_for_region, MIN2(reach, end_card), value);
@ -145,40 +144,33 @@ void SerialBlockOffsetTable::update_for_block_work(HeapWord* blk_start,
}
HeapWord* SerialBlockOffsetTable::block_start_reaching_into_card(const void* addr) const {
size_t index = _array->index_for(addr);
uint8_t offset;
while (true) {
offset = _array->offset_array(index);
if (offset < CardTable::card_size_in_words()) {
break;
}
uint8_t* entry = _array->entry_for_addr(addr);
uint8_t offset = *entry;
while (offset >= CardTable::card_size_in_words()) {
// The excess of the offset from N_words indicates a power of Base
// to go back by.
size_t n_cards_back = BOTConstants::entry_to_cards_back(offset);
index -= n_cards_back;
entry -= n_cards_back;
offset = *entry;
}
HeapWord* q = _array->address_for_index(index);
HeapWord* q = _array->addr_for_entry(entry);
return q - offset;
}
void SerialBlockOffsetTable::verify_for_block(HeapWord* blk_start, HeapWord* blk_end) const {
assert(is_crossing_card_boundary(blk_start, blk_end), "precondition");
const size_t start_card = _array->index_for(align_up_by_card_size(blk_start));
const size_t end_card = _array->index_for(blk_end - 1);
uint8_t* start_card = _array->entry_for_addr(align_up_by_card_size(blk_start));
uint8_t* end_card = _array->entry_for_addr(blk_end - 1);
// Check cards in [start_card, end_card]
assert(_array->offset_array(start_card) < CardTable::card_size_in_words(), "offset card");
assert(*start_card < CardTable::card_size_in_words(), "offset card");
for (size_t i = start_card + 1; i <= end_card; ++i) {
const uint8_t prev = _array->offset_array(i-1);
const uint8_t value = _array->offset_array(i);
if (prev != value) {
assert(value >= prev, "monotonic");
size_t n_cards_back = BOTConstants::entry_to_cards_back(value);
for (uint8_t* i = start_card + 1; i <= end_card; ++i) {
const uint8_t* prev = i - 1;
const uint8_t* value = i;
if (*prev != *value) {
assert(*value >= *prev, "monotonic");
size_t n_cards_back = BOTConstants::entry_to_cards_back(*value);
assert(start_card == (i - n_cards_back), "inv");
}
}

31
src/hotspot/share/gc/serial/serialBlockOffsetTable.hpp
View File

@ -46,16 +46,12 @@ class SerialBlockOffsetSharedArray: public CHeapObj<mtGC> {
// Array for keeping offsets for retrieving object start fast given an
// address.
VirtualSpace _vs;
uint8_t* _offset_array; // byte array keeping backwards offsets
void fill_range(size_t start, size_t num_cards, uint8_t offset) {
void* start_ptr = &_offset_array[start];
memset(start_ptr, offset, num_cards);
}
// Biased array-start of BOT array for fast BOT entry translation
uint8_t* _offset_base;
uint8_t offset_array(size_t index) const {
assert(index < _vs.committed_size(), "index out of range");
return _offset_array[index];
void fill_range(uint8_t* const start, size_t num_cards, uint8_t offset) {
memset(start, offset, num_cards);
}
// Return the number of slots needed for an offset array
@ -81,22 +77,21 @@ public:
// reserved region this table covers.
void resize(size_t new_word_size);
// Return the appropriate index into "_offset_array" for "p".
size_t index_for(const void* p) const;
// Mapping from address to object start array entry
uint8_t* entry_for_addr(const void* const p) const;
// Return the address indicating the start of the region corresponding to
// "index" in "_offset_array".
HeapWord* address_for_index(size_t index) const;
// Mapping from object start array entry to address of first word
HeapWord* addr_for_entry(const uint8_t* const p) const;
void set_offset_array(size_t index, HeapWord* high, HeapWord* low) {
assert(index < _vs.committed_size(), "index out of range");
void set_offset_array(uint8_t* const addr, HeapWord* high, HeapWord* low) {
assert(_vs.contains(addr), "Block offset address out of range");
assert(high >= low, "addresses out of order");
assert(pointer_delta(high, low) < CardTable::card_size_in_words(), "offset too large");
_offset_array[index] = checked_cast<uint8_t>(pointer_delta(high, low));
*addr = checked_cast<uint8_t>(pointer_delta(high, low));
}
void set_offset_array(size_t left, size_t right, uint8_t offset) {
assert(right < _vs.committed_size(), "right address out of range");
void set_offset_array(uint8_t* const left, uint8_t* const right, uint8_t offset) {
assert(_vs.contains(right), "right address out of range");
assert(left <= right, "precondition");
size_t num_cards = right - left + 1;

22
src/hotspot/share/gc/serial/serialBlockOffsetTable.inline.hpp
View File

@ -27,22 +27,18 @@
#include "gc/serial/serialBlockOffsetTable.hpp"
inline size_t SerialBlockOffsetSharedArray::index_for(const void* p) const {
char* pc = (char*)p;
assert(pc >= (char*)_reserved.start() &&
pc < (char*)_reserved.end(),
"p not in range.");
size_t delta = pointer_delta(pc, _reserved.start(), sizeof(char));
size_t result = delta >> CardTable::card_shift();
assert(result < _vs.committed_size(), "bad index from address");
inline uint8_t* SerialBlockOffsetSharedArray::entry_for_addr(const void* const p) const {
assert(_reserved.contains(p),
"out of bounds access to block offset array");
uint8_t* result = &_offset_base[uintptr_t(p) >> CardTable::card_shift()];
return result;
}
inline HeapWord* SerialBlockOffsetSharedArray::address_for_index(size_t index) const {
assert(index < _vs.committed_size(), "bad index");
HeapWord* result = _reserved.start() + (index << CardTable::card_shift_in_words());
assert(result >= _reserved.start() && result < _reserved.end(),
"bad address from index");
inline HeapWord* SerialBlockOffsetSharedArray::addr_for_entry(const uint8_t* const p) const {
size_t delta = pointer_delta(p, _offset_base, sizeof(uint8_t));
HeapWord* result = (HeapWord*) (delta << CardTable::card_shift());
assert(_reserved.contains(result),
"out of bounds accessor from block offset array");
return result;
}

2
src/hotspot/share/gc/serial/vmStructs_serial.hpp
View File

@ -58,7 +58,7 @@
\
nonstatic_field(SerialBlockOffsetSharedArray, _reserved, MemRegion) \
nonstatic_field(SerialBlockOffsetSharedArray, _vs, VirtualSpace) \
nonstatic_field(SerialBlockOffsetSharedArray, _offset_array, u_char*) \
nonstatic_field(SerialBlockOffsetSharedArray, _offset_base, u_char*) \
\
nonstatic_field(TenuredSpace, _offsets, SerialBlockOffsetTable) \
\

2
src/hotspot/share/gc/shared/cardTable.cpp
View File

@ -40,7 +40,6 @@
#endif
uint CardTable::_card_shift = 0;
uint CardTable::_card_shift_in_words = 0;
uint CardTable::_card_size = 0;
uint CardTable::_card_size_in_words = 0;
@ -51,7 +50,6 @@ void CardTable::initialize_card_size() {
_card_size = GCCardSizeInBytes;
_card_shift = log2i_exact(_card_size);
_card_size_in_words = _card_size / sizeof(HeapWord);
_card_shift_in_words = _card_shift - LogHeapWordSize;
log_info_p(gc, init)("CardTable entry size: " UINT32_FORMAT, _card_size);
}

5
src/hotspot/share/gc/shared/cardTable.hpp
View File

@ -73,7 +73,6 @@ protected:
// CardTable entry size
static uint _card_shift;
static uint _card_shift_in_words;
static uint _card_size;
static uint _card_size_in_words;
@ -183,10 +182,6 @@ public:
return _card_shift;
}
static uint card_shift_in_words() {
return _card_shift_in_words;
}
static uint card_size() {
return _card_size;
}