8136679: JFR event for adaptive IHOP
Reviewed-by: tbenson, mgerdin, sangheki, ehelin
/*
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* 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
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*
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* 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).
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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/g1BlockOffsetTable.inline.hpp"
#include "gc/g1/g1CollectedHeap.inline.hpp"
#include "gc/g1/heapRegion.hpp"
#include "gc/shared/space.hpp"
#include "oops/oop.inline.hpp"
#include "runtime/java.hpp"
#include "services/memTracker.hpp"
//////////////////////////////////////////////////////////////////////
// G1BlockOffsetSharedArray
//////////////////////////////////////////////////////////////////////
G1BlockOffsetSharedArray::G1BlockOffsetSharedArray(MemRegion heap, G1RegionToSpaceMapper* storage) :
_reserved(), _end(NULL), _listener(), _offset_array(NULL) {
_reserved = heap;
_end = NULL;
MemRegion bot_reserved = storage->reserved();
_offset_array = (u_char*)bot_reserved.start();
_end = _reserved.end();
storage->set_mapping_changed_listener(&_listener);
if (TraceBlockOffsetTable) {
gclog_or_tty->print_cr("G1BlockOffsetSharedArray::G1BlockOffsetSharedArray: ");
gclog_or_tty->print_cr(" "
" rs.base(): " PTR_FORMAT
" rs.size(): " SIZE_FORMAT
" rs end(): " PTR_FORMAT,
p2i(bot_reserved.start()), bot_reserved.byte_size(), p2i(bot_reserved.end()));
}
}
bool G1BlockOffsetSharedArray::is_card_boundary(HeapWord* p) const {
assert(p >= _reserved.start(), "just checking");
size_t delta = pointer_delta(p, _reserved.start());
return (delta & right_n_bits(LogN_words)) == (size_t)NoBits;
}
#ifdef ASSERT
void G1BlockOffsetSharedArray::check_index(size_t index, const char* msg) const {
assert((index) < (_reserved.word_size() >> LogN_words),
"%s - index: " SIZE_FORMAT ", _vs.committed_size: " SIZE_FORMAT,
msg, (index), (_reserved.word_size() >> LogN_words));
assert(G1CollectedHeap::heap()->is_in_exact(address_for_index_raw(index)),
"Index " SIZE_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)));
}
#endif // ASSERT
//////////////////////////////////////////////////////////////////////
// G1BlockOffsetArray
//////////////////////////////////////////////////////////////////////
G1BlockOffsetArray::G1BlockOffsetArray(G1BlockOffsetSharedArray* array,
MemRegion mr) :
G1BlockOffsetTable(mr.start(), mr.end()),
_unallocated_block(_bottom),
_array(array), _gsp(NULL) {
assert(_bottom <= _end, "arguments out of order");
}
void G1BlockOffsetArray::set_space(G1OffsetTableContigSpace* sp) {
_gsp = sp;
}
// The arguments follow the normal convention of denoting
// a right-open interval: [start, end)
void
G1BlockOffsetArray:: set_remainder_to_point_to_start(HeapWord* start, HeapWord* end) {
if (start >= end) {
// The start address is equal to the end address (or to
// the right of the end address) so there are not cards
// that need to be updated..
return;
}
// Write the backskip value for each region.
//
// offset
// card 2nd 3rd
// | +- 1st | |
// v v v v
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-
// |x|0|0|0|0|0|0|0|1|1|1|1|1|1| ... |1|1|1|1|2|2|2|2|2|2| ...
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-
// 11 19 75
// 12
//
// offset card is the card that points to the start of an object
// x - offset value of offset card
// 1st - start of first logarithmic region
// 0 corresponds to logarithmic value N_words + 0 and 2**(3 * 0) = 1
// 2nd - start of second logarithmic region
// 1 corresponds to logarithmic value N_words + 1 and 2**(3 * 1) = 8
// 3rd - start of third logarithmic region
// 2 corresponds to logarithmic value N_words + 2 and 2**(3 * 2) = 64
//
// integer below the block offset entry is an example of
// 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 =>
// back slip = 2**(3*(0x81 - N_words)) = 2**3) = 8
// Move back N (e.g., 8) entries and repeat with the
// value of the new entry
//
size_t start_card = _array->index_for(start);
size_t end_card = _array->index_for(end-1);
assert(start ==_array->address_for_index(start_card), "Precondition");
assert(end ==_array->address_for_index(end_card)+N_words, "Precondition");
set_remainder_to_point_to_start_incl(start_card, end_card); // closed interval
}
// Unlike the normal convention in this code, the argument here denotes
// a closed, inclusive interval: [start_card, end_card], cf set_remainder_to_point_to_start()
// above.
void
G1BlockOffsetArray::set_remainder_to_point_to_start_incl(size_t start_card, size_t end_card) {
if (start_card > end_card) {
return;
}
assert(start_card > _array->index_for(_bottom), "Cannot be first card");
assert(_array->offset_array(start_card-1) <= N_words,
"Offset card has an unexpected value");
size_t start_card_for_region = start_card;
u_char offset = max_jubyte;
for (int i = 0; i < BlockOffsetArray::N_powers; i++) {
// -1 so that the 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 + (BlockOffsetArray::power_to_cards_back(i+1) - 1);
offset = N_words + i;
if (reach >= end_card) {
_array->set_offset_array(start_card_for_region, end_card, offset);
start_card_for_region = reach + 1;
break;
}
_array->set_offset_array(start_card_for_region, reach, offset);
start_card_for_region = reach + 1;
}
assert(start_card_for_region > end_card, "Sanity check");
DEBUG_ONLY(check_all_cards(start_card, end_card);)
}
// 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 G1BlockOffsetArray::check_all_cards(size_t start_card, size_t end_card) const {
if (end_card < start_card) {
return;
}
guarantee(_array->offset_array(start_card) == N_words, "Wrong value in second card");
for (size_t c = start_card + 1; c <= end_card; c++ /* yeah! */) {
u_char entry = _array->offset_array(c);
if (c - start_card > BlockOffsetArray::power_to_cards_back(1)) {
guarantee(entry > N_words,
"Should be in logarithmic region - "
"entry: %u, "
"_array->offset_array(c): %u, "
"N_words: %u",
(uint)entry, (uint)_array->offset_array(c), (uint)N_words);
}
size_t backskip = BlockOffsetArray::entry_to_cards_back(entry);
size_t landing_card = c - backskip;
guarantee(landing_card >= (start_card - 1), "Inv");
if (landing_card >= start_card) {
guarantee(_array->offset_array(landing_card) <= entry,
"Monotonicity - landing_card offset: %u, "
"entry: %u",
(uint)_array->offset_array(landing_card), (uint)entry);
} else {
guarantee(landing_card == start_card - 1, "Tautology");
// Note that N_words is the maximum offset value
guarantee(_array->offset_array(landing_card) <= N_words,
"landing card offset: %u, "
"N_words: %u",
(uint)_array->offset_array(landing_card), (uint)N_words);
}
}
}
HeapWord* G1BlockOffsetArray::block_start_unsafe(const void* addr) {
assert(_bottom <= addr && addr < _end,
"addr must be covered by this Array");
// Must read this exactly once because it can be modified by parallel
// allocation.
HeapWord* ub = _unallocated_block;
if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) {
assert(ub < _end, "tautology (see above)");
return ub;
}
// Otherwise, find the block start using the table.
HeapWord* q = block_at_or_preceding(addr, false, 0);
return forward_to_block_containing_addr(q, addr);
}
// This duplicates a little code from the above: unavoidable.
HeapWord*
G1BlockOffsetArray::block_start_unsafe_const(const void* addr) const {
assert(_bottom <= addr && addr < _end,
"addr must be covered by this Array");
// Must read this exactly once because it can be modified by parallel
// allocation.
HeapWord* ub = _unallocated_block;
if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) {
assert(ub < _end, "tautology (see above)");
return ub;
}
// Otherwise, find the block start using the table.
HeapWord* q = block_at_or_preceding(addr, false, 0);
HeapWord* n = q + block_size(q);
return forward_to_block_containing_addr_const(q, n, addr);
}
HeapWord*
G1BlockOffsetArray::forward_to_block_containing_addr_slow(HeapWord* q,
HeapWord* n,
const void* addr) {
// We're not in the normal case. We need to handle an important subcase
// here: LAB allocation. An allocation previously recorded in the
// offset table was actually a lab allocation, and was divided into
// several objects subsequently. Fix this situation as we answer the
// query, by updating entries as we cross them.
// If the fist object's end q is at the card boundary. Start refining
// with the corresponding card (the value of the entry will be basically
// set to 0). If the object crosses the boundary -- start from the next card.
size_t n_index = _array->index_for(n);
size_t next_index = _array->index_for(n) + !_array->is_card_boundary(n);
// Calculate a consistent next boundary. If "n" is not at the boundary
// already, step to the boundary.
HeapWord* next_boundary = _array->address_for_index(n_index) +
(n_index == next_index ? 0 : N_words);
assert(next_boundary <= _array->_end,
"next_boundary is beyond the end of the covered region "
" next_boundary " PTR_FORMAT " _array->_end " PTR_FORMAT,
p2i(next_boundary), p2i(_array->_end));
if (addr >= gsp()->top()) return gsp()->top();
while (next_boundary < addr) {
while (n <= next_boundary) {
q = n;
oop obj = oop(q);
if (obj->klass_or_null() == NULL) return q;
n += block_size(q);
}
assert(q <= next_boundary && n > next_boundary, "Consequence of loop");
// [q, n) is the block that crosses the boundary.
alloc_block_work2(&next_boundary, &next_index, q, n);
}
return forward_to_block_containing_addr_const(q, n, addr);
}
// Note that the committed size of the covered space may have changed,
// so the table size might also wish to change.
void G1BlockOffsetArray::resize(size_t new_word_size) {
HeapWord* new_end = _bottom + new_word_size;
_end = new_end; // update _end
}
//
// threshold_
// | _index_
// v v
// +-------+-------+-------+-------+-------+
// | i-1 | i | i+1 | i+2 | i+3 |
// +-------+-------+-------+-------+-------+
// ( ^ ]
// block-start
//
void G1BlockOffsetArray::alloc_block_work2(HeapWord** threshold_, size_t* index_,
HeapWord* blk_start, HeapWord* blk_end) {
// For efficiency, do copy-in/copy-out.
HeapWord* threshold = *threshold_;
size_t index = *index_;
assert(blk_start != NULL && blk_end > blk_start,
"phantom block");
assert(blk_end > threshold, "should be past threshold");
assert(blk_start <= threshold, "blk_start should be at or before threshold");
assert(pointer_delta(threshold, blk_start) <= N_words,
"offset should be <= BlockOffsetSharedArray::N");
assert(G1CollectedHeap::heap()->is_in_reserved(blk_start),
"reference must be into the heap");
assert(G1CollectedHeap::heap()->is_in_reserved(blk_end-1),
"limit must be within the heap");
assert(threshold == _array->_reserved.start() + index*N_words,
"index must agree with threshold");
DEBUG_ONLY(size_t orig_index = index;)
// Mark the card that holds the offset into the block. Note
// that _next_offset_index and _next_offset_threshold are not
// updated until the end of this method.
_array->set_offset_array(index, threshold, blk_start);
// We need to now mark the subsequent cards that this blk spans.
// Index of card on which blk ends.
size_t end_index = _array->index_for(blk_end - 1);
// Are there more cards left to be updated?
if (index + 1 <= end_index) {
HeapWord* rem_st = _array->address_for_index(index + 1);
// Calculate rem_end this way because end_index
// may be the last valid index in the covered region.
HeapWord* rem_end = _array->address_for_index(end_index) + N_words;
set_remainder_to_point_to_start(rem_st, rem_end);
}
index = end_index + 1;
// Calculate threshold_ this way because end_index
// may be the last valid index in the covered region.
threshold = _array->address_for_index(end_index) + N_words;
assert(threshold >= blk_end, "Incorrect offset threshold");
// index_ and threshold_ updated here.
*threshold_ = threshold;
*index_ = index;
#ifdef ASSERT
// The offset can be 0 if the block starts on a boundary. That
// is checked by an assertion above.
size_t start_index = _array->index_for(blk_start);
HeapWord* boundary = _array->address_for_index(start_index);
assert((_array->offset_array(orig_index) == 0 && blk_start == boundary) ||
(_array->offset_array(orig_index) > 0 && _array->offset_array(orig_index) <= N_words),
"offset array should have been set - "
"orig_index offset: %u, "
"blk_start: " PTR_FORMAT ", "
"boundary: " PTR_FORMAT,
(uint)_array->offset_array(orig_index),
p2i(blk_start), p2i(boundary));
for (size_t j = orig_index + 1; j <= end_index; j++) {
assert(_array->offset_array(j) > 0 &&
_array->offset_array(j) <=
(u_char) (N_words+BlockOffsetArray::N_powers-1),
"offset array should have been set - "
"%u not > 0 OR %u not <= %u",
(uint) _array->offset_array(j),
(uint) _array->offset_array(j),
(uint) (N_words+BlockOffsetArray::N_powers-1));
}
#endif
}
void G1BlockOffsetArray::verify() const {
assert(gsp()->bottom() < gsp()->top(), "Only non-empty regions should be verified.");
size_t start_card = _array->index_for(gsp()->bottom());
size_t end_card = _array->index_for(gsp()->top() - 1);
for (size_t current_card = start_card; current_card < end_card; current_card++) {
u_char entry = _array->offset_array(current_card);
if (entry < N_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 = _array->address_for_index(current_card);
HeapWord* obj_end = card_address - entry;
while (obj_end < card_address) {
HeapWord* obj = obj_end;
size_t obj_size = block_size(obj);
obj_end = obj + obj_size;
guarantee(obj_end > obj && obj_end <= gsp()->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(gsp()->top()));
}
} else {
// Because we refine the BOT based on which cards are dirty there is not much we can verify here.
// We need to make sure that we are going backwards and that we don't pass the start of the
// corresponding heap region. But that is about all we can verify.
size_t backskip = BlockOffsetArray::entry_to_cards_back(entry);
guarantee(backskip >= 1, "Must be going back at least one card.");
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);
HeapWord* backskip_address = _array->address_for_index(current_card - backskip);
guarantee(backskip_address >= gsp()->bottom(),
"Going backwards beyond bottom of the region: bottom: " PTR_FORMAT ", backskip_address: " PTR_FORMAT,
p2i(gsp()->bottom()), p2i(backskip_address));
}
}
}
#ifndef PRODUCT
void
G1BlockOffsetArray::print_on(outputStream* out) {
size_t from_index = _array->index_for(_bottom);
size_t to_index = _array->index_for(_end);
out->print_cr(">> BOT for area [" PTR_FORMAT "," PTR_FORMAT ") "
"cards [" SIZE_FORMAT "," SIZE_FORMAT ")",
p2i(_bottom), p2i(_end), from_index, to_index);
for (size_t i = from_index; i < to_index; ++i) {
out->print_cr(" entry " SIZE_FORMAT_W(8) " | " PTR_FORMAT " : %3u",
i, p2i(_array->address_for_index(i)),
(uint) _array->offset_array(i));
}
}
#endif // !PRODUCT
//////////////////////////////////////////////////////////////////////
// G1BlockOffsetArrayContigSpace
//////////////////////////////////////////////////////////////////////
HeapWord*
G1BlockOffsetArrayContigSpace::block_start_unsafe(const void* addr) {
assert(_bottom <= addr && addr < _end,
"addr must be covered by this Array");
HeapWord* q = block_at_or_preceding(addr, true, _next_offset_index-1);
return forward_to_block_containing_addr(q, addr);
}
HeapWord*
G1BlockOffsetArrayContigSpace::
block_start_unsafe_const(const void* addr) const {
assert(_bottom <= addr && addr < _end,
"addr must be covered by this Array");
HeapWord* q = block_at_or_preceding(addr, true, _next_offset_index-1);
HeapWord* n = q + block_size(q);
return forward_to_block_containing_addr_const(q, n, addr);
}
G1BlockOffsetArrayContigSpace::
G1BlockOffsetArrayContigSpace(G1BlockOffsetSharedArray* array,
MemRegion mr) :
G1BlockOffsetArray(array, mr)
{
_next_offset_threshold = NULL;
_next_offset_index = 0;
}
HeapWord* G1BlockOffsetArrayContigSpace::initialize_threshold_raw() {
assert(!G1CollectedHeap::heap()->is_in_reserved(_array->_offset_array),
"just checking");
_next_offset_index = _array->index_for_raw(_bottom);
_next_offset_index++;
_next_offset_threshold =
_array->address_for_index_raw(_next_offset_index);
return _next_offset_threshold;
}
void G1BlockOffsetArrayContigSpace::zero_bottom_entry_raw() {
assert(!G1CollectedHeap::heap()->is_in_reserved(_array->_offset_array),
"just checking");
size_t bottom_index = _array->index_for_raw(_bottom);
assert(_array->address_for_index_raw(bottom_index) == _bottom,
"Precondition of call");
_array->set_offset_array_raw(bottom_index, 0);
}
HeapWord* G1BlockOffsetArrayContigSpace::initialize_threshold() {
assert(!G1CollectedHeap::heap()->is_in_reserved(_array->_offset_array),
"just checking");
_next_offset_index = _array->index_for(_bottom);
_next_offset_index++;
_next_offset_threshold =
_array->address_for_index(_next_offset_index);
return _next_offset_threshold;
}
void G1BlockOffsetArrayContigSpace::set_for_starts_humongous(HeapWord* obj_top, size_t fill_size) {
// The first BOT entry should have offset 0.
reset_bot();
alloc_block(_bottom, obj_top);
if (fill_size > 0) {
alloc_block(obj_top, fill_size);
}
}
#ifndef PRODUCT
void G1BlockOffsetArrayContigSpace::print_on(outputStream* out) {
G1BlockOffsetArray::print_on(out);
out->print_cr(" next offset threshold: " PTR_FORMAT, p2i(_next_offset_threshold));
out->print_cr(" next offset index: " SIZE_FORMAT, _next_offset_index);
}
#endif // !PRODUCT