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/*
* Copyright (c) 2013, 2018, 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/g1/g1CardCounts.hpp"
#include "gc/g1/g1CollectedHeap.inline.hpp"
#include "gc/shared/cardTableBarrierSet.hpp"
#include "services/memTracker.hpp"
#include "utilities/copy.hpp"
void G1CardCountsMappingChangedListener::on_commit(uint start_idx, size_t num_regions, bool zero_filled) {
if (zero_filled) {
return;
}
MemRegion mr(G1CollectedHeap::heap()->bottom_addr_for_region(start_idx), num_regions * HeapRegion::GrainWords);
_counts->clear_range(mr);
}
size_t G1CardCounts::compute_size(size_t mem_region_size_in_words) {
// We keep card counts for every card, so the size of the card counts table must
// be the same as the card table.
return G1CardTable::compute_size(mem_region_size_in_words);
}
size_t G1CardCounts::heap_map_factor() {
// See G1CardCounts::compute_size() why we reuse the card table value.
return G1CardTable::heap_map_factor();
}
void G1CardCounts::clear_range(size_t from_card_num, size_t to_card_num) {
if (has_count_table()) {
assert(from_card_num < to_card_num,
"Wrong order? from: " SIZE_FORMAT ", to: " SIZE_FORMAT,
from_card_num, to_card_num);
Copy::fill_to_bytes(&_card_counts[from_card_num], (to_card_num - from_card_num));
}
}
G1CardCounts::G1CardCounts(G1CollectedHeap *g1h):
_listener(), _g1h(g1h), _ct(NULL), _card_counts(NULL), _reserved_max_card_num(0), _ct_bot(NULL) {
_listener.set_cardcounts(this);
}
void G1CardCounts::initialize(G1RegionToSpaceMapper* mapper) {
assert(_g1h->reserved().byte_size() > 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");
_ct = _g1h->card_table();
_ct_bot = _ct->byte_for_const(_g1h->reserved().start());
_card_counts = (jubyte*) mapper->reserved().start();
_reserved_max_card_num = mapper->reserved().byte_size();
mapper->set_mapping_changed_listener(&_listener);
}
}
uint G1CardCounts::add_card_count(CardValue* 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);
assert(card_num < _reserved_max_card_num,
"Card " SIZE_FORMAT " outside of card counts table (max size " SIZE_FORMAT ")",
card_num, _reserved_max_card_num);
count = (uint) _card_counts[card_num];
if (count < G1ConcRSHotCardLimit) {
_card_counts[card_num] =
(jubyte)(MIN2((uintx)(_card_counts[card_num] + 1), G1ConcRSHotCardLimit));
}
}
return count;
}
bool G1CardCounts::is_hot(uint count) {
return (count >= G1ConcRSHotCardLimit);
}
void G1CardCounts::clear_region(HeapRegion* hr) {
MemRegion mr(hr->bottom(), hr->end());
clear_range(mr);
}
void G1CardCounts::clear_range(MemRegion mr) {
if (has_count_table()) {
const CardValue* from_card_ptr = _ct->byte_for_const(mr.start());
// We use the last address in the range as the range could represent the
// last region in the heap. In which case trying to find the card will be an
// OOB access to the card table.
const CardValue* last_card_ptr = _ct->byte_for_const(mr.last());
#ifdef ASSERT
HeapWord* start_addr = _ct->addr_for(from_card_ptr);
assert(start_addr == mr.start(), "MemRegion start must be aligned to a card.");
HeapWord* last_addr = _ct->addr_for(last_card_ptr);
assert((last_addr + G1CardTable::card_size_in_words()) == mr.end(), "MemRegion end must be aligned to a card.");
#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);
}
}
class G1CardCountsClearClosure : public HeapRegionClosure {
private:
G1CardCounts* _card_counts;
public:
G1CardCountsClearClosure(G1CardCounts* card_counts) :
HeapRegionClosure(), _card_counts(card_counts) { }
virtual bool do_heap_region(HeapRegion* r) {
_card_counts->clear_region(r);
return false;
}
};
void G1CardCounts::clear_all() {
assert(SafepointSynchronize::is_at_safepoint(), "don't call this otherwise");
G1CardCountsClearClosure cl(this);
_g1h->heap_region_iterate(&cl);
}
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