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8329603: G1: Merge G1BlockOffsetTablePart into G1BlockOffsetTable

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Reviewed-by: ayang, iwalulya
This commit is contained in:
Guoxiong Li 2024-04-09 13:22:24 +00:00
parent 2fcb816858
commit 5fb5e6c8f0
9 changed files with 81 additions and 140 deletions
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6
src/hotspot/share/cds/filemap.cpp
View File

@ -2227,11 +2227,11 @@ void FileMapInfo::fixup_mapped_heap_region() {
if (ArchiveHeapLoader::is_mapped()) {
assert(!_mapped_heap_memregion.is_empty(), "sanity");
// Populate the archive regions' G1BlockOffsetTableParts. That ensures
// fast G1BlockOffsetTablePart::block_start operations for any given address
// Populate the archive regions' G1BlockOffsetTables. That ensures
// fast G1BlockOffsetTable::block_start operations for any given address
// within the archive regions when trying to find start of an object
// (e.g. during card table scanning).
G1CollectedHeap::heap()->populate_archive_regions_bot_part(_mapped_heap_memregion);
G1CollectedHeap::heap()->populate_archive_regions_bot(_mapped_heap_memregion);
}
}

112
src/hotspot/share/gc/g1/g1BlockOffsetTable.cpp
View File

@ -31,10 +31,6 @@
#include "oops/oop.inline.hpp"
#include "runtime/java.hpp"
//////////////////////////////////////////////////////////////////////
// G1BlockOffsetTable
//////////////////////////////////////////////////////////////////////
G1BlockOffsetTable::G1BlockOffsetTable(MemRegion heap, G1RegionToSpaceMapper* storage) :
_reserved(heap), _offset_base(nullptr) {
@ -62,14 +58,6 @@ void G1BlockOffsetTable::check_address(uint8_t* addr, const char* msg) const {
}
#endif // ASSERT
//////////////////////////////////////////////////////////////////////
// G1BlockOffsetTablePart
//////////////////////////////////////////////////////////////////////
G1BlockOffsetTablePart::G1BlockOffsetTablePart(G1BlockOffsetTable* array, HeapRegion* hr) :
_bot(array),
_hr(hr) {}
// Write the backskip value for each region.
//
// offset
@ -102,10 +90,9 @@ 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(uint8_t* start_card, uint8_t* end_card) {
void G1BlockOffsetTable::set_remainder_to_point_to_start_incl(uint8_t* start_card, uint8_t* end_card) {
assert(start_card <= end_card, "precondition");
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(),
assert(offset_array(start_card-1) < CardTable::card_size_in_words(),
"Offset card has an unexpected value");
uint8_t* start_card_for_region = start_card;
uint8_t offset = UINT8_MAX;
@ -116,11 +103,11 @@ void G1BlockOffsetTablePart::set_remainder_to_point_to_start_incl(uint8_t* start
uint8_t* 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);
set_offset_array(start_card_for_region, end_card, offset);
start_card_for_region = reach + 1;
break;
}
_bot->set_offset_array(start_card_for_region, reach, offset);
set_offset_array(start_card_for_region, reach, offset);
start_card_for_region = reach + 1;
}
assert(start_card_for_region > end_card, "Sanity check");
@ -131,36 +118,36 @@ void G1BlockOffsetTablePart::set_remainder_to_point_to_start_incl(uint8_t* start
// 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(uint8_t* start_card, uint8_t* end_card) const {
void G1BlockOffsetTable::check_all_cards(uint8_t* start_card, uint8_t* 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");
guarantee(offset_array(start_card) == CardTable::card_size_in_words(), "Wrong value in second card");
for (uint8_t* c = start_card + 1; c <= end_card; c++ /* yeah! */) {
uint8_t entry = _bot->offset_array(c);
uint8_t entry = offset_array(c);
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, "
"_array->offset_array(c): %u, "
"N_words: %u",
(uint)entry, (uint)_bot->offset_array(c), CardTable::card_size_in_words());
(uint)entry, (uint)offset_array(c), CardTable::card_size_in_words());
}
size_t backskip = BOTConstants::entry_to_cards_back(entry);
uint8_t* landing_card = c - backskip;
guarantee(landing_card >= (start_card - 1), "Inv");
if (landing_card >= start_card) {
guarantee(_bot->offset_array(landing_card) <= entry,
guarantee(offset_array(landing_card) <= entry,
"Monotonicity - landing_card offset: %u, "
"entry: %u",
(uint)_bot->offset_array(landing_card), (uint)entry);
(uint)offset_array(landing_card), (uint)entry);
} else {
guarantee(landing_card == start_card - 1, "Tautology");
// Note that N_words is the maximum offset value
guarantee(_bot->offset_array(landing_card) < CardTable::card_size_in_words(),
guarantee(offset_array(landing_card) < CardTable::card_size_in_words(),
"landing card offset: %u, "
"N_words: %u",
(uint)_bot->offset_array(landing_card), (uint)CardTable::card_size_in_words());
(uint)offset_array(landing_card), (uint)CardTable::card_size_in_words());
}
}
}
@ -176,10 +163,9 @@ void G1BlockOffsetTablePart::check_all_cards(uint8_t* start_card, uint8_t* end_c
// ( ^ ]
// blk_start
//
void G1BlockOffsetTablePart::update_for_block_work(HeapWord* blk_start,
HeapWord* blk_end) {
void G1BlockOffsetTable::update_for_block_work(HeapWord* blk_start, HeapWord* blk_end) {
HeapWord* const cur_card_boundary = align_up_by_card_size(blk_start);
uint8_t* const offset_card = _bot->entry_for_addr(cur_card_boundary);
uint8_t* const offset_card = entry_for_addr(cur_card_boundary);
assert(blk_start != nullptr && blk_end > blk_start,
"phantom block");
@ -191,16 +177,16 @@ 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->addr_for_entry(offset_card),
assert(cur_card_boundary == 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(offset_card, cur_card_boundary, blk_start);
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.
uint8_t* end_card = _bot->entry_for_addr(blk_end - 1);
uint8_t* end_card = entry_for_addr(blk_end - 1);
// Are there more cards left to be updated?
if (offset_card + 1 <= end_card) {
@ -210,54 +196,53 @@ void G1BlockOffsetTablePart::update_for_block_work(HeapWord* blk_start,
#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->addr_for_entry(end_card) + CardTable::card_size_in_words();
HeapWord* new_card_boundary = 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.
uint8_t* 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()),
uint8_t* previous_card = entry_for_addr(blk_start);
HeapWord* boundary = addr_for_entry(previous_card);
assert((offset_array(offset_card) == 0 && blk_start == boundary) ||
(offset_array(offset_card) > 0 && 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(offset_card),
(uint)offset_array(offset_card),
p2i(blk_start), p2i(boundary));
for (uint8_t* j = offset_card + 1; j <= end_card; j++) {
assert(_bot->offset_array(j) > 0 &&
_bot->offset_array(j) <=
(uint8_t) (CardTable::card_size_in_words() + BOTConstants::N_powers - 1),
assert(offset_array(j) > 0 &&
offset_array(j) <= (uint8_t) (CardTable::card_size_in_words() + BOTConstants::N_powers - 1),
"offset array should have been set - "
"%u not > 0 OR %u not <= %u",
(uint) _bot->offset_array(j),
(uint) _bot->offset_array(j),
(uint) offset_array(j),
(uint) offset_array(j),
(uint) (CardTable::card_size_in_words() + BOTConstants::N_powers - 1));
}
#endif
}
void G1BlockOffsetTablePart::verify() const {
assert(_hr->bottom() < _hr->top(), "Only non-empty regions should be verified.");
uint8_t* start_card = _bot->entry_for_addr(_hr->bottom());
uint8_t* end_card = _bot->entry_for_addr(_hr->top() - 1);
void G1BlockOffsetTable::verify(const HeapRegion* hr) const {
assert(hr->bottom() < hr->top(), "Only non-empty regions should be verified.");
uint8_t* start_card = entry_for_addr(hr->bottom());
uint8_t* end_card = entry_for_addr(hr->top() - 1);
for (uint8_t* current_card = start_card; current_card < end_card; current_card++) {
uint8_t entry = _bot->offset_array(current_card);
uint8_t entry = 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->addr_for_entry(current_card);
HeapWord* card_address = addr_for_entry(current_card);
HeapWord* obj_end = card_address - entry;
while (obj_end < card_address) {
HeapWord* obj = obj_end;
size_t obj_size = _hr->block_size(obj);
size_t obj_size = hr->block_size(obj);
obj_end = obj + obj_size;
guarantee(obj_end > obj && obj_end <= _hr->top(),
guarantee(obj_end > obj && obj_end <= hr->top(),
"Invalid object end. obj: " PTR_FORMAT " obj_size: " SIZE_FORMAT " obj_end: " PTR_FORMAT " top: " PTR_FORMAT,
p2i(obj), obj_size, p2i(obj_end), p2i(_hr->top()));
p2i(obj), obj_size, p2i(obj_end), p2i(hr->top()));
}
} else {
// Because we refine the BOT based on which cards are dirty there is not much we can verify here.
@ -271,31 +256,16 @@ void G1BlockOffsetTablePart::verify() const {
"Going backwards beyond the start_card. start_card: " SIZE_FORMAT " current_card: " SIZE_FORMAT " backskip: " SIZE_FORMAT,
p2i(start_card), p2i(current_card), backskip);
HeapWord* backskip_address = _bot->addr_for_entry(current_card - backskip);
guarantee(backskip_address >= _hr->bottom(),
HeapWord* backskip_address = 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));
p2i(hr->bottom()), p2i(backskip_address));
}
}
}
#ifndef PRODUCT
void G1BlockOffsetTablePart::print_on(outputStream* out) {
uint8_t* from_card = _bot->entry_for_addr(_hr->bottom());
uint8_t* 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()), p2i(from_card), p2i(to_card));
for (uint8_t* i = from_card; i < to_card; ++i) {
out->print_cr(" entry " SIZE_FORMAT_W(8) " | " PTR_FORMAT " : %3u",
p2i(i), p2i(_bot->addr_for_entry(i)),
(uint) _bot->offset_array(i));
}
}
#endif // !PRODUCT
void G1BlockOffsetTablePart::set_for_starts_humongous(HeapWord* obj_top, size_t fill_size) {
update_for_block(_hr->bottom(), obj_top);
void G1BlockOffsetTable::set_for_starts_humongous(HeapRegion* hr, HeapWord* obj_top, size_t fill_size) {
update_for_block(hr->bottom(), obj_top);
if (fill_size > 0) {
update_for_block(obj_top, fill_size);
}

59
src/hotspot/share/gc/g1/g1BlockOffsetTable.hpp
View File

@ -33,18 +33,13 @@
#include "utilities/globalDefinitions.hpp"
// Forward declarations
class G1BlockOffsetTable;
class HeapRegion;
// This implementation of "G1BlockOffsetTable" divides the covered region
// into "N"-word subregions (where "N" = 2^"LogN". An array with an entry
// for each such subregion indicates how far back one must go to find the
// start of the chunk that includes the first word of the subregion.
//
// Each G1BlockOffsetTablePart is owned by a HeapRegion.
class G1BlockOffsetTable: public CHeapObj<mtGC> {
friend class G1BlockOffsetTablePart;
friend class VMStructs;
private:
@ -73,6 +68,23 @@ private:
void check_address(uint8_t* addr, const char* msg) const NOT_DEBUG_RETURN;
// 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(uint8_t* start, uint8_t* 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(uint8_t* left_card, uint8_t* right_card) const NOT_DEBUG_RETURN;
static HeapWord* align_up_by_card_size(HeapWord* const addr) {
return align_up(addr, CardTable::card_size());
}
void update_for_block(HeapWord* blk_start, size_t size) {
update_for_block(blk_start, blk_start + size);
}
public:
// Return the number of slots needed for an offset array
@ -96,35 +108,7 @@ public:
// Mapping from object start array entry to address of first word
HeapWord* addr_for_entry(const uint8_t* const p) const;
};
class G1BlockOffsetTablePart {
friend class G1BlockOffsetTable;
friend class VMStructs;
private:
// This is the global BlockOffsetTable.
G1BlockOffsetTable* _bot;
// The region that owns this part of the BOT.
HeapRegion* _hr;
// 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(uint8_t* start, uint8_t* 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(uint8_t* left_card, uint8_t* right_card) const NOT_DEBUG_RETURN;
static HeapWord* align_up_by_card_size(HeapWord* const addr) {
return align_up(addr, CardTable::card_size());
}
void update_for_block(HeapWord* blk_start, size_t size) {
update_for_block(blk_start, blk_start + size);
}
public:
static bool is_crossing_card_boundary(HeapWord* const obj_start,
HeapWord* const obj_end) {
HeapWord* cur_card_boundary = align_up_by_card_size(obj_start);
@ -132,10 +116,7 @@ public:
return obj_end > cur_card_boundary;
}
// The elements of the array are initialized to zero.
G1BlockOffsetTablePart(G1BlockOffsetTable* array, HeapRegion* hr);
void verify() const;
void verify(const HeapRegion* hr) const;
// Returns the address of the start of the block reaching into the card containing
// "addr".
@ -147,9 +128,7 @@ public:
}
}
void set_for_starts_humongous(HeapWord* obj_top, size_t fill_size);
void print_on(outputStream* out) PRODUCT_RETURN;
void set_for_starts_humongous(HeapRegion* hr, HeapWord* obj_top, size_t fill_size);
};
#endif // SHARE_GC_G1_G1BLOCKOFFSETTABLE_HPP

21
src/hotspot/share/gc/g1/g1BlockOffsetTable.inline.hpp
View File

@ -32,29 +32,20 @@
#include "runtime/atomic.hpp"
#include "oops/oop.inline.hpp"
inline HeapWord* G1BlockOffsetTablePart::block_start_reaching_into_card(const void* addr) const {
assert(addr >= _hr->bottom() && addr < _hr->top(), "invalid address");
inline HeapWord* G1BlockOffsetTable::block_start_reaching_into_card(const void* addr) const {
assert(_reserved.contains(addr), "invalid address");
#ifdef ASSERT
if (!_hr->is_continues_humongous()) {
// For non-ContinuesHumongous regions, the first obj always starts from bottom.
uint8_t 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
uint8_t* entry = _bot->entry_for_addr(addr);
uint8_t offset = _bot->offset_array(entry);
uint8_t* entry = entry_for_addr(addr);
uint8_t offset = 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);
entry -= n_cards_back;
offset = _bot->offset_array(entry);
offset = offset_array(entry);
}
assert(offset < CardTable::card_size_in_words(), "offset too large");
HeapWord* q = _bot->addr_for_entry(entry);
HeapWord* q = addr_for_entry(entry);
return q - offset;
}

2
src/hotspot/share/gc/g1/g1CollectedHeap.cpp
View File

@ -532,7 +532,7 @@ HeapWord* G1CollectedHeap::alloc_archive_region(size_t word_size, HeapWord* pref
return start_addr;
}
void G1CollectedHeap::populate_archive_regions_bot_part(MemRegion range) {
void G1CollectedHeap::populate_archive_regions_bot(MemRegion range) {
assert(!is_init_completed(), "Expect to be called at JVM init time");
iterate_regions_in_range(range,

4
src/hotspot/share/gc/g1/g1CollectedHeap.hpp
View File

@ -717,9 +717,9 @@ public:
// in the CDS archive.
HeapWord* alloc_archive_region(size_t word_size, HeapWord* preferred_addr);
// Populate the G1BlockOffsetTablePart for archived regions with the given
// Populate the G1BlockOffsetTable for archived regions with the given
// memory range.
void populate_archive_regions_bot_part(MemRegion range);
void populate_archive_regions_bot(MemRegion range);
// For the specified range, uncommit the containing G1 regions
// which had been allocated by alloc_archive_regions. This should be called

8
src/hotspot/share/gc/g1/g1HeapRegion.cpp
View File

@ -188,7 +188,7 @@ void HeapRegion::set_starts_humongous(HeapWord* obj_top, size_t fill_size) {
_type.set_starts_humongous();
_humongous_start_region = this;
_bot_part.set_for_starts_humongous(obj_top, fill_size);
_bot->set_for_starts_humongous(this, obj_top, fill_size);
}
void HeapRegion::set_continues_humongous(HeapRegion* first_hr) {
@ -219,7 +219,7 @@ HeapRegion::HeapRegion(uint hrm_index,
_bottom(mr.start()),
_end(mr.end()),
_top(nullptr),
_bot_part(bot, this),
_bot(bot),
_pre_dummy_top(nullptr),
_rem_set(nullptr),
_hrm_index(hrm_index),
@ -694,7 +694,7 @@ bool HeapRegion::verify(VerifyOption vo) const {
// Only regions in old generation contain valid BOT.
if (!is_empty() && !is_young()) {
_bot_part.verify();
_bot->verify(this);
}
if (is_humongous()) {
@ -723,7 +723,7 @@ void HeapRegion::mangle_unused_area() {
#endif
void HeapRegion::update_bot_for_block(HeapWord* start, HeapWord* end) {
_bot_part.update_for_block(start, end);
_bot->update_for_block(start, end);
}
void HeapRegion::object_iterate(ObjectClosure* blk) {

2
src/hotspot/share/gc/g1/g1HeapRegion.hpp
View File

@ -74,7 +74,7 @@ class HeapRegion : public CHeapObj<mtGC> {
HeapWord* volatile _top;
G1BlockOffsetTablePart _bot_part;
G1BlockOffsetTable* _bot;
// When we need to retire an allocation region, while other threads
// are also concurrently trying to allocate into it, we typically

7
src/hotspot/share/gc/g1/g1HeapRegion.inline.hpp
View File

@ -100,12 +100,13 @@ inline HeapWord* HeapRegion::advance_to_block_containing_addr(const void* addr,
cur_block = next_block;
// Because the BOT is precise, we should never step into the next card
// (i.e. crossing the card boundary).
assert(!G1BlockOffsetTablePart::is_crossing_card_boundary(cur_block, (HeapWord*)addr), "must be");
assert(!G1BlockOffsetTable::is_crossing_card_boundary(cur_block, (HeapWord*)addr), "must be");
}
}
inline HeapWord* HeapRegion::block_start(const void* addr, HeapWord* const pb) const {
HeapWord* first_block = _bot_part.block_start_reaching_into_card(addr);
assert(addr >= bottom() && addr < top(), "invalid address");
HeapWord* first_block = _bot->block_start_reaching_into_card(addr);
return advance_to_block_containing_addr(addr, pb, first_block);
}
@ -262,7 +263,7 @@ inline void HeapRegion::update_bot_for_obj(HeapWord* obj_start, size_t obj_size)
HR_FORMAT_PARAMS(this),
p2i(obj_start), p2i(obj_end));
_bot_part.update_for_block(obj_start, obj_end);
_bot->update_for_block(obj_start, obj_end);
}
inline HeapWord* HeapRegion::parsable_bottom() const {