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/*
* Copyright (c) 2013, 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/g1CardCounts.hpp"
#include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
#include "gc_implementation/g1/g1CollectorPolicy.hpp"
#include "gc_implementation/g1/g1GCPhaseTimes.hpp"
#include "memory/cardTableModRefBS.hpp"
#include "services/memTracker.hpp"
#include "utilities/copy.hpp"
void G1CardCounts::clear_range(size_t from_card_num, size_t to_card_num) {
if (has_count_table()) {
check_card_num(from_card_num,
err_msg("from card num out of range: "SIZE_FORMAT, from_card_num));
assert(from_card_num < to_card_num,
err_msg("Wrong order? from: " SIZE_FORMAT ", to: "SIZE_FORMAT,
from_card_num, to_card_num));
assert(to_card_num <= _committed_max_card_num,
err_msg("to card num out of range: "
"to: "SIZE_FORMAT ", "
"max: "SIZE_FORMAT,
to_card_num, _committed_max_card_num));
to_card_num = MIN2(_committed_max_card_num, to_card_num);
Copy::fill_to_bytes(&_card_counts[from_card_num], (to_card_num - from_card_num));
}
}
G1CardCounts::G1CardCounts(G1CollectedHeap *g1h):
_g1h(g1h), _card_counts(NULL),
_reserved_max_card_num(0), _committed_max_card_num(0),
_committed_size(0) {}
void G1CardCounts::initialize() {
assert(_g1h->max_capacity() > 0, "initialization order");
assert(_g1h->capacity() == 0, "initialization order");
if (G1ConcRSHotCardLimit > 0) {
// The max value we can store in the counts table is
// max_jubyte. Guarantee the value of the hot
// threshold limit is no more than this.
guarantee(G1ConcRSHotCardLimit <= max_jubyte, "sanity");
ModRefBarrierSet* bs = _g1h->mr_bs();
guarantee(bs->is_a(BarrierSet::CardTableModRef), "Precondition");
_ct_bs = (CardTableModRefBS*)bs;
_ct_bot = _ct_bs->byte_for_const(_g1h->reserved_region().start());
// Allocate/Reserve the counts table
size_t reserved_bytes = _g1h->max_capacity();
_reserved_max_card_num = reserved_bytes >> CardTableModRefBS::card_shift;
size_t reserved_size = _reserved_max_card_num * sizeof(jbyte);
ReservedSpace rs(ReservedSpace::allocation_align_size_up(reserved_size));
if (!rs.is_reserved()) {
warning("Could not reserve enough space for the card counts table");
guarantee(!has_reserved_count_table(), "should be NULL");
return;
}
MemTracker::record_virtual_memory_type((address)rs.base(), mtGC);
_card_counts_storage.initialize(rs, 0);
_card_counts = (jubyte*) _card_counts_storage.low();
}
}
void G1CardCounts::resize(size_t heap_capacity) {
// Expand the card counts table to handle a heap with the given capacity.
if (!has_reserved_count_table()) {
// Don't expand if we failed to reserve the card counts table.
return;
}
assert(_committed_size ==
ReservedSpace::allocation_align_size_up(_committed_size),
err_msg("Unaligned? committed_size: " SIZE_FORMAT, _committed_size));
// Verify that the committed space for the card counts
// matches our committed max card num.
size_t prev_committed_size = _committed_size;
size_t prev_committed_card_num = prev_committed_size / sizeof(jbyte);
assert(prev_committed_card_num == _committed_max_card_num,
err_msg("Card mismatch: "
"prev: " SIZE_FORMAT ", "
"committed: "SIZE_FORMAT,
prev_committed_card_num, _committed_max_card_num));
size_t new_size = (heap_capacity >> CardTableModRefBS::card_shift) * sizeof(jbyte);
size_t new_committed_size = ReservedSpace::allocation_align_size_up(new_size);
size_t new_committed_card_num =
MIN2(_reserved_max_card_num, new_committed_size / sizeof(jbyte));
if (_committed_max_card_num < new_committed_card_num) {
// we need to expand the backing store for the card counts
size_t expand_size = new_committed_size - prev_committed_size;
if (!_card_counts_storage.expand_by(expand_size)) {
warning("Card counts table backing store commit failure");
return;
}
assert(_card_counts_storage.committed_size() == new_committed_size,
"expansion commit failure");
_committed_size = new_committed_size;
_committed_max_card_num = new_committed_card_num;
clear_range(prev_committed_card_num, _committed_max_card_num);
}
}
uint G1CardCounts::add_card_count(jbyte* card_ptr) {
// Returns the number of times the card has been refined.
// If we failed to reserve/commit the counts table, return 0.
// If card_ptr is beyond the committed end of the counts table,
// return 0.
// Otherwise return the actual count.
// Unless G1ConcRSHotCardLimit has been set appropriately,
// returning 0 will result in the card being considered
// cold and will be refined immediately.
uint count = 0;
if (has_count_table()) {
size_t card_num = ptr_2_card_num(card_ptr);
if (card_num < _committed_max_card_num) {
count = (uint) _card_counts[card_num];
if (count < G1ConcRSHotCardLimit) {
_card_counts[card_num] += 1;
}
assert(_card_counts[card_num] <= G1ConcRSHotCardLimit,
err_msg("Refinement count overflow? "
"new count: "UINT32_FORMAT,
(uint) _card_counts[card_num]));
}
}
return count;
}
bool G1CardCounts::is_hot(uint count) {
return (count >= G1ConcRSHotCardLimit);
}
void G1CardCounts::clear_region(HeapRegion* hr) {
assert(!hr->isHumongous(), "Should have been cleared");
if (has_count_table()) {
HeapWord* bottom = hr->bottom();
// We use the last address in hr as hr could be the
// last region in the heap. In which case trying to find
// the card for hr->end() will be an OOB accesss to the
// card table.
HeapWord* last = hr->end() - 1;
assert(_g1h->g1_committed().contains(last),
err_msg("last not in committed: "
"last: " PTR_FORMAT ", "
"committed: [" PTR_FORMAT ", " PTR_FORMAT ")",
last,
_g1h->g1_committed().start(),
_g1h->g1_committed().end()));
const jbyte* from_card_ptr = _ct_bs->byte_for_const(bottom);
const jbyte* last_card_ptr = _ct_bs->byte_for_const(last);
#ifdef ASSERT
HeapWord* start_addr = _ct_bs->addr_for(from_card_ptr);
assert(start_addr == hr->bottom(), "alignment");
HeapWord* last_addr = _ct_bs->addr_for(last_card_ptr);
assert((last_addr + CardTableModRefBS::card_size_in_words) == hr->end(), "alignment");
#endif // ASSERT
// Clear the counts for the (exclusive) card range.
size_t from_card_num = ptr_2_card_num(from_card_ptr);
size_t to_card_num = ptr_2_card_num(last_card_ptr) + 1;
clear_range(from_card_num, to_card_num);
}
}
void G1CardCounts::clear_all() {
assert(SafepointSynchronize::is_at_safepoint(), "don't call this otherwise");
clear_range((size_t)0, _committed_max_card_num);
}
G1CardCounts::~G1CardCounts() {
if (has_reserved_count_table()) {
_card_counts_storage.release();
}
}
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