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jdk/hotspot/src/share/vm/gc_implementation/g1/heapRegionRemSet.cpp
Y. Srinivas Ramakrishna 18f3386a98 6711316: Open source the Garbage-First garbage collector 
First mercurial integration of the code for the Garbage-First garbage collector.

Reviewed-by: apetrusenko, iveresov, jmasa, sgoldman, tonyp, ysr
2008-06-05 15:57:56 -07:00

1443 lines
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/*
* Copyright 2001-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*
*/
#include "incls/_precompiled.incl"
#include "incls/_heapRegionRemSet.cpp.incl"
#define HRRS_VERBOSE 0
#define PRT_COUNT_OCCUPIED 1
// OtherRegionsTable
class PerRegionTable: public CHeapObj {
friend class OtherRegionsTable;
friend class HeapRegionRemSetIterator;
HeapRegion* _hr;
BitMap _bm;
#if PRT_COUNT_OCCUPIED
jint _occupied;
#endif
PerRegionTable* _next_free;
PerRegionTable* next_free() { return _next_free; }
void set_next_free(PerRegionTable* prt) { _next_free = prt; }
static PerRegionTable* _free_list;
#ifdef _MSC_VER
// For some reason even though the classes are marked as friend they are unable
// to access CardsPerRegion when private/protected. Only the windows c++ compiler
// says this Sun CC and linux gcc don't have a problem with access when private
public:
#endif // _MSC_VER
enum SomePrivateConstants {
CardsPerRegion = HeapRegion::GrainBytes >> CardTableModRefBS::card_shift
};
protected:
// We need access in order to union things into the base table.
BitMap* bm() { return &_bm; }
void recount_occupied() {
_occupied = (jint) bm()->count_one_bits();
}
PerRegionTable(HeapRegion* hr) :
_hr(hr),
#if PRT_COUNT_OCCUPIED
_occupied(0),
#endif
_bm(CardsPerRegion, false /* in-resource-area */)
{}
static void free(PerRegionTable* prt) {
while (true) {
PerRegionTable* fl = _free_list;
prt->set_next_free(fl);
PerRegionTable* res =
(PerRegionTable*)
Atomic::cmpxchg_ptr(prt, &_free_list, fl);
if (res == fl) return;
}
ShouldNotReachHere();
}
static PerRegionTable* alloc(HeapRegion* hr) {
PerRegionTable* fl = _free_list;
while (fl != NULL) {
PerRegionTable* nxt = fl->next_free();
PerRegionTable* res =
(PerRegionTable*)
Atomic::cmpxchg_ptr(nxt, &_free_list, fl);
if (res == fl) {
fl->init(hr);
return fl;
} else {
fl = _free_list;
}
}
assert(fl == NULL, "Loop condition.");
return new PerRegionTable(hr);
}
void add_card_work(short from_card, bool par) {
if (!_bm.at(from_card)) {
if (par) {
if (_bm.par_at_put(from_card, 1)) {
#if PRT_COUNT_OCCUPIED
Atomic::inc(&_occupied);
#endif
}
} else {
_bm.at_put(from_card, 1);
#if PRT_COUNT_OCCUPIED
_occupied++;
#endif
}
}
}
void add_reference_work(oop* from, bool par) {
// Must make this robust in case "from" is not in "_hr", because of
// concurrency.
#if HRRS_VERBOSE
gclog_or_tty->print_cr(" PRT::Add_reference_work(" PTR_FORMAT "->" PTR_FORMAT").",
from, *from);
#endif
HeapRegion* loc_hr = hr();
// If the test below fails, then this table was reused concurrently
// with this operation. This is OK, since the old table was coarsened,
// and adding a bit to the new table is never incorrect.
if (loc_hr->is_in_reserved(from)) {
size_t hw_offset = pointer_delta((HeapWord*)from, loc_hr->bottom());
size_t from_card =
hw_offset >>
(CardTableModRefBS::card_shift - LogHeapWordSize);
add_card_work((short) from_card, par);
}
}
public:
HeapRegion* hr() const { return _hr; }
#if PRT_COUNT_OCCUPIED
jint occupied() const {
// Overkill, but if we ever need it...
// guarantee(_occupied == _bm.count_one_bits(), "Check");
return _occupied;
}
#else
jint occupied() const {
return _bm.count_one_bits();
}
#endif
void init(HeapRegion* hr) {
_hr = hr;
#if PRT_COUNT_OCCUPIED
_occupied = 0;
#endif
_bm.clear();
}
void add_reference(oop* from) {
add_reference_work(from, /*parallel*/ true);
}
void seq_add_reference(oop* from) {
add_reference_work(from, /*parallel*/ false);
}
void scrub(CardTableModRefBS* ctbs, BitMap* card_bm) {
HeapWord* hr_bot = hr()->bottom();
int hr_first_card_index = ctbs->index_for(hr_bot);
bm()->set_intersection_at_offset(*card_bm, hr_first_card_index);
#if PRT_COUNT_OCCUPIED
recount_occupied();
#endif
}
void add_card(short from_card_index) {
add_card_work(from_card_index, /*parallel*/ true);
}
void seq_add_card(short from_card_index) {
add_card_work(from_card_index, /*parallel*/ false);
}
// (Destructively) union the bitmap of the current table into the given
// bitmap (which is assumed to be of the same size.)
void union_bitmap_into(BitMap* bm) {
bm->set_union(_bm);
}
// Mem size in bytes.
size_t mem_size() const {
return sizeof(this) + _bm.size_in_words() * HeapWordSize;
}
static size_t fl_mem_size() {
PerRegionTable* cur = _free_list;
size_t res = 0;
while (cur != NULL) {
res += sizeof(PerRegionTable);
cur = cur->next_free();
}
return res;
}
// Requires "from" to be in "hr()".
bool contains_reference(oop* from) const {
assert(hr()->is_in_reserved(from), "Precondition.");
size_t card_ind = pointer_delta(from, hr()->bottom(),
CardTableModRefBS::card_size);
return _bm.at(card_ind);
}
};
PerRegionTable* PerRegionTable::_free_list = NULL;
#define COUNT_PAR_EXPANDS 0
#if COUNT_PAR_EXPANDS
static jint n_par_expands = 0;
static jint n_par_contracts = 0;
static jint par_expand_list_len = 0;
static jint max_par_expand_list_len = 0;
static void print_par_expand() {
Atomic::inc(&n_par_expands);
Atomic::inc(&par_expand_list_len);
if (par_expand_list_len > max_par_expand_list_len) {
max_par_expand_list_len = par_expand_list_len;
}
if ((n_par_expands % 10) == 0) {
gclog_or_tty->print_cr("\n\n%d par expands: %d contracts, "
"len = %d, max_len = %d\n.",
n_par_expands, n_par_contracts, par_expand_list_len,
max_par_expand_list_len);
}
}
#endif
class PosParPRT: public PerRegionTable {
PerRegionTable** _par_tables;
enum SomePrivateConstants {
ReserveParTableExpansion = 1
};
void par_expand() {
int n = HeapRegionRemSet::num_par_rem_sets()-1;
if (n <= 0) return;
if (_par_tables == NULL) {
PerRegionTable* res =
(PerRegionTable*)
Atomic::cmpxchg_ptr((PerRegionTable*)ReserveParTableExpansion,
&_par_tables, NULL);
if (res != NULL) return;
// Otherwise, we reserved the right to do the expansion.
PerRegionTable** ptables = NEW_C_HEAP_ARRAY(PerRegionTable*, n);
for (int i = 0; i < n; i++) {
PerRegionTable* ptable = PerRegionTable::alloc(hr());
ptables[i] = ptable;
}
// Here we do not need an atomic.
_par_tables = ptables;
#if COUNT_PAR_EXPANDS
print_par_expand();
#endif
// We must put this table on the expanded list.
PosParPRT* exp_head = _par_expanded_list;
while (true) {
set_next_par_expanded(exp_head);
PosParPRT* res =
(PosParPRT*)
Atomic::cmpxchg_ptr(this, &_par_expanded_list, exp_head);
if (res == exp_head) return;
// Otherwise.
exp_head = res;
}
ShouldNotReachHere();
}
}
void par_contract() {
assert(_par_tables != NULL, "Precondition.");
int n = HeapRegionRemSet::num_par_rem_sets()-1;
for (int i = 0; i < n; i++) {
_par_tables[i]->union_bitmap_into(bm());
PerRegionTable::free(_par_tables[i]);
_par_tables[i] = NULL;
}
#if PRT_COUNT_OCCUPIED
// We must recount the "occupied."
recount_occupied();
#endif
FREE_C_HEAP_ARRAY(PerRegionTable*, _par_tables);
_par_tables = NULL;
#if COUNT_PAR_EXPANDS
Atomic::inc(&n_par_contracts);
Atomic::dec(&par_expand_list_len);
#endif
}
static PerRegionTable** _par_table_fl;
PosParPRT* _next;
static PosParPRT* _free_list;
PerRegionTable** par_tables() const {
assert(uintptr_t(NULL) == 0, "Assumption.");
if (uintptr_t(_par_tables) <= ReserveParTableExpansion)
return NULL;
else
return _par_tables;
}
PosParPRT* _next_par_expanded;
PosParPRT* next_par_expanded() { return _next_par_expanded; }
void set_next_par_expanded(PosParPRT* ppprt) { _next_par_expanded = ppprt; }
static PosParPRT* _par_expanded_list;
public:
PosParPRT(HeapRegion* hr) : PerRegionTable(hr), _par_tables(NULL) {}
jint occupied() const {
jint res = PerRegionTable::occupied();
if (par_tables() != NULL) {
for (int i = 0; i < HeapRegionRemSet::num_par_rem_sets()-1; i++) {
res += par_tables()[i]->occupied();
}
}
return res;
}
void init(HeapRegion* hr) {
PerRegionTable::init(hr);
_next = NULL;
if (par_tables() != NULL) {
for (int i = 0; i < HeapRegionRemSet::num_par_rem_sets()-1; i++) {
par_tables()[i]->init(hr);
}
}
}
static void free(PosParPRT* prt) {
while (true) {
PosParPRT* fl = _free_list;
prt->set_next(fl);
PosParPRT* res =
(PosParPRT*)
Atomic::cmpxchg_ptr(prt, &_free_list, fl);
if (res == fl) return;
}
ShouldNotReachHere();
}
static PosParPRT* alloc(HeapRegion* hr) {
PosParPRT* fl = _free_list;
while (fl != NULL) {
PosParPRT* nxt = fl->next();
PosParPRT* res =
(PosParPRT*)
Atomic::cmpxchg_ptr(nxt, &_free_list, fl);
if (res == fl) {
fl->init(hr);
return fl;
} else {
fl = _free_list;
}
}
assert(fl == NULL, "Loop condition.");
return new PosParPRT(hr);
}
PosParPRT* next() const { return _next; }
void set_next(PosParPRT* nxt) { _next = nxt; }
PosParPRT** next_addr() { return &_next; }
void add_reference(oop* from, int tid) {
// Expand if necessary.
PerRegionTable** pt = par_tables();
if (par_tables() == NULL && tid > 0 && hr()->is_gc_alloc_region()) {
par_expand();
pt = par_tables();
}
if (pt != NULL) {
// We always have to assume that mods to table 0 are in parallel,
// because of the claiming scheme in parallel expansion. A thread
// with tid != 0 that finds the table to be NULL, but doesn't succeed
// in claiming the right of expanding it, will end up in the else
// clause of the above if test. That thread could be delayed, and a
// thread 0 add reference could see the table expanded, and come
// here. Both threads would be adding in parallel. But we get to
// not use atomics for tids > 0.
if (tid == 0) {
PerRegionTable::add_reference(from);
} else {
pt[tid-1]->seq_add_reference(from);
}
} else {
// Not expanded -- add to the base table.
PerRegionTable::add_reference(from);
}
}
void scrub(CardTableModRefBS* ctbs, BitMap* card_bm) {
assert(_par_tables == NULL, "Precondition");
PerRegionTable::scrub(ctbs, card_bm);
}
size_t mem_size() const {
size_t res =
PerRegionTable::mem_size() + sizeof(this) - sizeof(PerRegionTable);
if (_par_tables != NULL) {
for (int i = 0; i < HeapRegionRemSet::num_par_rem_sets()-1; i++) {
res += _par_tables[i]->mem_size();
}
}
return res;
}
static size_t fl_mem_size() {
PosParPRT* cur = _free_list;
size_t res = 0;
while (cur != NULL) {
res += sizeof(PosParPRT);
cur = cur->next();
}
return res;
}
bool contains_reference(oop* from) const {
if (PerRegionTable::contains_reference(from)) return true;
if (_par_tables != NULL) {
for (int i = 0; i < HeapRegionRemSet::num_par_rem_sets()-1; i++) {
if (_par_tables[i]->contains_reference(from)) return true;
}
}
return false;
}
static void par_contract_all();
};
void PosParPRT::par_contract_all() {
PosParPRT* hd = _par_expanded_list;
while (hd != NULL) {
PosParPRT* nxt = hd->next_par_expanded();
PosParPRT* res =
(PosParPRT*)
Atomic::cmpxchg_ptr(nxt, &_par_expanded_list, hd);
if (res == hd) {
// We claimed the right to contract this table.
hd->set_next_par_expanded(NULL);
hd->par_contract();
hd = _par_expanded_list;
} else {
hd = res;
}
}
}
PosParPRT* PosParPRT::_free_list = NULL;
PosParPRT* PosParPRT::_par_expanded_list = NULL;
jint OtherRegionsTable::_cache_probes = 0;
jint OtherRegionsTable::_cache_hits = 0;
size_t OtherRegionsTable::_max_fine_entries = 0;
size_t OtherRegionsTable::_mod_max_fine_entries_mask = 0;
#if SAMPLE_FOR_EVICTION
size_t OtherRegionsTable::_fine_eviction_stride = 0;
size_t OtherRegionsTable::_fine_eviction_sample_size = 0;
#endif
OtherRegionsTable::OtherRegionsTable(HeapRegion* hr) :
_g1h(G1CollectedHeap::heap()),
_m(Mutex::leaf, "An OtherRegionsTable lock", true),
_hr(hr),
_coarse_map(G1CollectedHeap::heap()->max_regions(),
false /* in-resource-area */),
_fine_grain_regions(NULL),
_n_fine_entries(0), _n_coarse_entries(0),
#if SAMPLE_FOR_EVICTION
_fine_eviction_start(0),
#endif
_sparse_table(hr)
{
typedef PosParPRT* PosParPRTPtr;
if (_max_fine_entries == 0) {
assert(_mod_max_fine_entries_mask == 0, "Both or none.");
_max_fine_entries = (1 << G1LogRSRegionEntries);
_mod_max_fine_entries_mask = _max_fine_entries - 1;
#if SAMPLE_FOR_EVICTION
assert(_fine_eviction_sample_size == 0
&& _fine_eviction_stride == 0, "All init at same time.");
_fine_eviction_sample_size = MAX2((size_t)4, (size_t)G1LogRSRegionEntries);
_fine_eviction_stride = _max_fine_entries / _fine_eviction_sample_size;
#endif
}
_fine_grain_regions = new PosParPRTPtr[_max_fine_entries];
if (_fine_grain_regions == NULL)
vm_exit_out_of_memory(sizeof(void*)*_max_fine_entries,
"Failed to allocate _fine_grain_entries.");
for (size_t i = 0; i < _max_fine_entries; i++) {
_fine_grain_regions[i] = NULL;
}
}
int** OtherRegionsTable::_from_card_cache = NULL;
size_t OtherRegionsTable::_from_card_cache_max_regions = 0;
size_t OtherRegionsTable::_from_card_cache_mem_size = 0;
void OtherRegionsTable::init_from_card_cache(size_t max_regions) {
_from_card_cache_max_regions = max_regions;
int n_par_rs = HeapRegionRemSet::num_par_rem_sets();
_from_card_cache = NEW_C_HEAP_ARRAY(int*, n_par_rs);
for (int i = 0; i < n_par_rs; i++) {
_from_card_cache[i] = NEW_C_HEAP_ARRAY(int, max_regions);
for (size_t j = 0; j < max_regions; j++) {
_from_card_cache[i][j] = -1; // An invalid value.
}
}
_from_card_cache_mem_size = n_par_rs * max_regions * sizeof(int);
}
void OtherRegionsTable::shrink_from_card_cache(size_t new_n_regs) {
for (int i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
assert(new_n_regs <= _from_card_cache_max_regions, "Must be within max.");
for (size_t j = new_n_regs; j < _from_card_cache_max_regions; j++) {
_from_card_cache[i][j] = -1; // An invalid value.
}
}
}
#ifndef PRODUCT
void OtherRegionsTable::print_from_card_cache() {
for (int i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
for (size_t j = 0; j < _from_card_cache_max_regions; j++) {
gclog_or_tty->print_cr("_from_card_cache[%d][%d] = %d.",
i, j, _from_card_cache[i][j]);
}
}
}
#endif
void OtherRegionsTable::add_reference(oop* from, int tid) {
size_t cur_hrs_ind = hr()->hrs_index();
#if HRRS_VERBOSE
gclog_or_tty->print_cr("ORT::add_reference_work(" PTR_FORMAT "->" PTR_FORMAT ").",
from, *from);
#endif
int from_card = (int)(uintptr_t(from) >> CardTableModRefBS::card_shift);
#if HRRS_VERBOSE
gclog_or_tty->print_cr("Table for [" PTR_FORMAT "...): card %d (cache = %d)",
hr()->bottom(), from_card,
_from_card_cache[tid][cur_hrs_ind]);
#endif
#define COUNT_CACHE 0
#if COUNT_CACHE
jint p = Atomic::add(1, &_cache_probes);
if ((p % 10000) == 0) {
jint hits = _cache_hits;
gclog_or_tty->print_cr("%d/%d = %5.2f%% RS cache hits.",
_cache_hits, p, 100.0* (float)hits/(float)p);
}
#endif
if (from_card == _from_card_cache[tid][cur_hrs_ind]) {
#if HRRS_VERBOSE
gclog_or_tty->print_cr(" from-card cache hit.");
#endif
#if COUNT_CACHE
Atomic::inc(&_cache_hits);
#endif
assert(contains_reference(from), "We just added it!");
return;
} else {
_from_card_cache[tid][cur_hrs_ind] = from_card;
}
// Note that this may be a continued H region.
HeapRegion* from_hr = _g1h->heap_region_containing_raw(from);
size_t from_hrs_ind = (size_t)from_hr->hrs_index();
// If the region is already coarsened, return.
if (_coarse_map.at(from_hrs_ind)) {
#if HRRS_VERBOSE
gclog_or_tty->print_cr(" coarse map hit.");
#endif
assert(contains_reference(from), "We just added it!");
return;
}
// Otherwise find a per-region table to add it to.
size_t ind = from_hrs_ind & _mod_max_fine_entries_mask;
PosParPRT* prt = find_region_table(ind, from_hr);
if (prt == NULL) {
MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag);
// Confirm that it's really not there...
prt = find_region_table(ind, from_hr);
if (prt == NULL) {
uintptr_t from_hr_bot_card_index =
uintptr_t(from_hr->bottom())
>> CardTableModRefBS::card_shift;
int card_index = from_card - from_hr_bot_card_index;
assert(0 <= card_index && card_index < PosParPRT::CardsPerRegion,
"Must be in range.");
if (G1HRRSUseSparseTable &&
_sparse_table.add_card((short) from_hrs_ind, card_index)) {
if (G1RecordHRRSOops) {
HeapRegionRemSet::record(hr(), from);
#if HRRS_VERBOSE
gclog_or_tty->print(" Added card " PTR_FORMAT " to region "
"[" PTR_FORMAT "...) for ref " PTR_FORMAT ".\n",
align_size_down(uintptr_t(from),
CardTableModRefBS::card_size),
hr()->bottom(), from);
#endif
}
#if HRRS_VERBOSE
gclog_or_tty->print_cr(" added card to sparse table.");
#endif
assert(contains_reference_locked(from), "We just added it!");
return;
} else {
#if HRRS_VERBOSE
gclog_or_tty->print_cr(" [tid %d] sparse table entry "
"overflow(f: %d, t: %d)",
tid, from_hrs_ind, cur_hrs_ind);
#endif
}
// Otherwise, transfer from sparse to fine-grain.
short cards[SparsePRTEntry::CardsPerEntry];
if (G1HRRSUseSparseTable) {
bool res = _sparse_table.get_cards((short) from_hrs_ind, &cards[0]);
assert(res, "There should have been an entry");
}
if (_n_fine_entries == _max_fine_entries) {
prt = delete_region_table();
} else {
prt = PosParPRT::alloc(from_hr);
}
prt->init(from_hr);
// Record the outgoing pointer in the from_region's outgoing bitmap.
from_hr->rem_set()->add_outgoing_reference(hr());
PosParPRT* first_prt = _fine_grain_regions[ind];
prt->set_next(first_prt); // XXX Maybe move to init?
_fine_grain_regions[ind] = prt;
_n_fine_entries++;
// Add in the cards from the sparse table.
if (G1HRRSUseSparseTable) {
for (int i = 0; i < SparsePRTEntry::CardsPerEntry; i++) {
short c = cards[i];
if (c != SparsePRTEntry::NullEntry) {
prt->add_card(c);
}
}
// Now we can delete the sparse entry.
bool res = _sparse_table.delete_entry((short) from_hrs_ind);
assert(res, "It should have been there.");
}
}
assert(prt != NULL && prt->hr() == from_hr, "consequence");
}
// Note that we can't assert "prt->hr() == from_hr", because of the
// possibility of concurrent reuse. But see head comment of
// OtherRegionsTable for why this is OK.
assert(prt != NULL, "Inv");
prt->add_reference(from, tid);
if (G1RecordHRRSOops) {
HeapRegionRemSet::record(hr(), from);
#if HRRS_VERBOSE
gclog_or_tty->print("Added card " PTR_FORMAT " to region "
"[" PTR_FORMAT "...) for ref " PTR_FORMAT ".\n",
align_size_down(uintptr_t(from),
CardTableModRefBS::card_size),
hr()->bottom(), from);
#endif
}
assert(contains_reference(from), "We just added it!");
}
PosParPRT*
OtherRegionsTable::find_region_table(size_t ind, HeapRegion* hr) const {
assert(0 <= ind && ind < _max_fine_entries, "Preconditions.");
PosParPRT* prt = _fine_grain_regions[ind];
while (prt != NULL && prt->hr() != hr) {
prt = prt->next();
}
// Loop postcondition is the method postcondition.
return prt;
}
#define DRT_CENSUS 0
#if DRT_CENSUS
static const int HistoSize = 6;
static int global_histo[HistoSize] = { 0, 0, 0, 0, 0, 0 };
static int coarsenings = 0;
static int occ_sum = 0;
#endif
jint OtherRegionsTable::_n_coarsenings = 0;
PosParPRT* OtherRegionsTable::delete_region_table() {
#if DRT_CENSUS
int histo[HistoSize] = { 0, 0, 0, 0, 0, 0 };
const int histo_limits[] = { 1, 4, 16, 64, 256, 2048 };
#endif
assert(_m.owned_by_self(), "Precondition");
assert(_n_fine_entries == _max_fine_entries, "Precondition");
PosParPRT* max = NULL;
jint max_occ = 0;
PosParPRT** max_prev;
size_t max_ind;
#if SAMPLE_FOR_EVICTION
size_t i = _fine_eviction_start;
for (size_t k = 0; k < _fine_eviction_sample_size; k++) {
size_t ii = i;
// Make sure we get a non-NULL sample.
while (_fine_grain_regions[ii] == NULL) {
ii++;
if (ii == _max_fine_entries) ii = 0;
guarantee(ii != i, "We must find one.");
}
PosParPRT** prev = &_fine_grain_regions[ii];
PosParPRT* cur = *prev;
while (cur != NULL) {
jint cur_occ = cur->occupied();
if (max == NULL || cur_occ > max_occ) {
max = cur;
max_prev = prev;
max_ind = i;
max_occ = cur_occ;
}
prev = cur->next_addr();
cur = cur->next();
}
i = i + _fine_eviction_stride;
if (i >= _n_fine_entries) i = i - _n_fine_entries;
}
_fine_eviction_start++;
if (_fine_eviction_start >= _n_fine_entries)
_fine_eviction_start -= _n_fine_entries;
#else
for (int i = 0; i < _max_fine_entries; i++) {
PosParPRT** prev = &_fine_grain_regions[i];
PosParPRT* cur = *prev;
while (cur != NULL) {
jint cur_occ = cur->occupied();
#if DRT_CENSUS
for (int k = 0; k < HistoSize; k++) {
if (cur_occ <= histo_limits[k]) {
histo[k]++; global_histo[k]++; break;
}
}
#endif
if (max == NULL || cur_occ > max_occ) {
max = cur;
max_prev = prev;
max_ind = i;
max_occ = cur_occ;
}
prev = cur->next_addr();
cur = cur->next();
}
}
#endif
// XXX
guarantee(max != NULL, "Since _n_fine_entries > 0");
#if DRT_CENSUS
gclog_or_tty->print_cr("In a coarsening: histo of occs:");
for (int k = 0; k < HistoSize; k++) {
gclog_or_tty->print_cr(" <= %4d: %5d.", histo_limits[k], histo[k]);
}
coarsenings++;
occ_sum += max_occ;
if ((coarsenings % 100) == 0) {
gclog_or_tty->print_cr("\ncoarsenings = %d; global summary:", coarsenings);
for (int k = 0; k < HistoSize; k++) {
gclog_or_tty->print_cr(" <= %4d: %5d.", histo_limits[k], global_histo[k]);
}
gclog_or_tty->print_cr("Avg occ of deleted region = %6.2f.",
(float)occ_sum/(float)coarsenings);
}
#endif
// Set the corresponding coarse bit.
int max_hrs_index = max->hr()->hrs_index();
if (!_coarse_map.at(max_hrs_index)) {
_coarse_map.at_put(max_hrs_index, true);
_n_coarse_entries++;
#if 0
gclog_or_tty->print("Coarsened entry in region [" PTR_FORMAT "...] "
"for region [" PTR_FORMAT "...] (%d coarse entries).\n",
hr()->bottom(),
max->hr()->bottom(),
_n_coarse_entries);
#endif
}
// Unsplice.
*max_prev = max->next();
Atomic::inc(&_n_coarsenings);
_n_fine_entries--;
return max;
}
// At present, this must be called stop-world single-threaded.
void OtherRegionsTable::scrub(CardTableModRefBS* ctbs,
BitMap* region_bm, BitMap* card_bm) {
// First eliminated garbage regions from the coarse map.
if (G1RSScrubVerbose)
gclog_or_tty->print_cr("Scrubbing region %d:", hr()->hrs_index());
assert(_coarse_map.size() == region_bm->size(), "Precondition");
if (G1RSScrubVerbose)
gclog_or_tty->print(" Coarse map: before = %d...", _n_coarse_entries);
_coarse_map.set_intersection(*region_bm);
_n_coarse_entries = _coarse_map.count_one_bits();
if (G1RSScrubVerbose)
gclog_or_tty->print_cr(" after = %d.", _n_coarse_entries);
// Now do the fine-grained maps.
for (size_t i = 0; i < _max_fine_entries; i++) {
PosParPRT* cur = _fine_grain_regions[i];
PosParPRT** prev = &_fine_grain_regions[i];
while (cur != NULL) {
PosParPRT* nxt = cur->next();
// If the entire region is dead, eliminate.
if (G1RSScrubVerbose)
gclog_or_tty->print_cr(" For other region %d:", cur->hr()->hrs_index());
if (!region_bm->at(cur->hr()->hrs_index())) {
*prev = nxt;
cur->set_next(NULL);
_n_fine_entries--;
if (G1RSScrubVerbose)
gclog_or_tty->print_cr(" deleted via region map.");
PosParPRT::free(cur);
} else {
// Do fine-grain elimination.
if (G1RSScrubVerbose)
gclog_or_tty->print(" occ: before = %4d.", cur->occupied());
cur->scrub(ctbs, card_bm);
if (G1RSScrubVerbose)
gclog_or_tty->print_cr(" after = %4d.", cur->occupied());
// Did that empty the table completely?
if (cur->occupied() == 0) {
*prev = nxt;
cur->set_next(NULL);
_n_fine_entries--;
PosParPRT::free(cur);
} else {
prev = cur->next_addr();
}
}
cur = nxt;
}
}
// Since we may have deleted a from_card_cache entry from the RS, clear
// the FCC.
clear_fcc();
}
size_t OtherRegionsTable::occupied() const {
// Cast away const in this case.
MutexLockerEx x((Mutex*)&_m, Mutex::_no_safepoint_check_flag);
size_t sum = occ_fine();
sum += occ_sparse();
sum += occ_coarse();
return sum;
}
size_t OtherRegionsTable::occ_fine() const {
size_t sum = 0;
for (size_t i = 0; i < _max_fine_entries; i++) {
PosParPRT* cur = _fine_grain_regions[i];
while (cur != NULL) {
sum += cur->occupied();
cur = cur->next();
}
}
return sum;
}
size_t OtherRegionsTable::occ_coarse() const {
return (_n_coarse_entries * PosParPRT::CardsPerRegion);
}
size_t OtherRegionsTable::occ_sparse() const {
return _sparse_table.occupied();
}
size_t OtherRegionsTable::mem_size() const {
// Cast away const in this case.
MutexLockerEx x((Mutex*)&_m, Mutex::_no_safepoint_check_flag);
size_t sum = 0;
for (size_t i = 0; i < _max_fine_entries; i++) {
PosParPRT* cur = _fine_grain_regions[i];
while (cur != NULL) {
sum += cur->mem_size();
cur = cur->next();
}
}
sum += (sizeof(PosParPRT*) * _max_fine_entries);
sum += (_coarse_map.size_in_words() * HeapWordSize);
sum += (_sparse_table.mem_size());
sum += sizeof(*this) - sizeof(_sparse_table); // Avoid double counting above.
return sum;
}
size_t OtherRegionsTable::static_mem_size() {
return _from_card_cache_mem_size;
}
size_t OtherRegionsTable::fl_mem_size() {
return PerRegionTable::fl_mem_size() + PosParPRT::fl_mem_size();
}
void OtherRegionsTable::clear_fcc() {
for (int i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
_from_card_cache[i][hr()->hrs_index()] = -1;
}
}
void OtherRegionsTable::clear() {
MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag);
for (size_t i = 0; i < _max_fine_entries; i++) {
PosParPRT* cur = _fine_grain_regions[i];
while (cur != NULL) {
PosParPRT* nxt = cur->next();
PosParPRT::free(cur);
cur = nxt;
}
_fine_grain_regions[i] = NULL;
}
_sparse_table.clear();
_coarse_map.clear();
_n_fine_entries = 0;
_n_coarse_entries = 0;
clear_fcc();
}
void OtherRegionsTable::clear_incoming_entry(HeapRegion* from_hr) {
MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag);
size_t hrs_ind = (size_t)from_hr->hrs_index();
size_t ind = hrs_ind & _mod_max_fine_entries_mask;
if (del_single_region_table(ind, from_hr)) {
assert(!_coarse_map.at(hrs_ind), "Inv");
} else {
_coarse_map.par_at_put(hrs_ind, 0);
}
// Check to see if any of the fcc entries come from here.
int hr_ind = hr()->hrs_index();
for (int tid = 0; tid < HeapRegionRemSet::num_par_rem_sets(); tid++) {
int fcc_ent = _from_card_cache[tid][hr_ind];
if (fcc_ent != -1) {
HeapWord* card_addr = (HeapWord*)
(uintptr_t(fcc_ent) << CardTableModRefBS::card_shift);
if (hr()->is_in_reserved(card_addr)) {
// Clear the from card cache.
_from_card_cache[tid][hr_ind] = -1;
}
}
}
}
bool OtherRegionsTable::del_single_region_table(size_t ind,
HeapRegion* hr) {
assert(0 <= ind && ind < _max_fine_entries, "Preconditions.");
PosParPRT** prev_addr = &_fine_grain_regions[ind];
PosParPRT* prt = *prev_addr;
while (prt != NULL && prt->hr() != hr) {
prev_addr = prt->next_addr();
prt = prt->next();
}
if (prt != NULL) {
assert(prt->hr() == hr, "Loop postcondition.");
*prev_addr = prt->next();
PosParPRT::free(prt);
_n_fine_entries--;
return true;
} else {
return false;
}
}
bool OtherRegionsTable::contains_reference(oop* from) const {
// Cast away const in this case.
MutexLockerEx x((Mutex*)&_m, Mutex::_no_safepoint_check_flag);
return contains_reference_locked(from);
}
bool OtherRegionsTable::contains_reference_locked(oop* from) const {
HeapRegion* hr = _g1h->heap_region_containing_raw(from);
if (hr == NULL) return false;
size_t hr_ind = hr->hrs_index();
// Is this region in the coarse map?
if (_coarse_map.at(hr_ind)) return true;
PosParPRT* prt = find_region_table(hr_ind & _mod_max_fine_entries_mask,
hr);
if (prt != NULL) {
return prt->contains_reference(from);
} else {
uintptr_t from_card =
(uintptr_t(from) >> CardTableModRefBS::card_shift);
uintptr_t hr_bot_card_index =
uintptr_t(hr->bottom()) >> CardTableModRefBS::card_shift;
assert(from_card >= hr_bot_card_index, "Inv");
int card_index = from_card - hr_bot_card_index;
return _sparse_table.contains_card((short)hr_ind, card_index);
}
}
bool HeapRegionRemSet::_par_traversal = false;
void HeapRegionRemSet::set_par_traversal(bool b) {
assert(_par_traversal != b, "Proper alternation...");
_par_traversal = b;
}
int HeapRegionRemSet::num_par_rem_sets() {
// We always have at least two, so that a mutator thread can claim an
// id and add to a rem set.
return (int) MAX2(ParallelGCThreads, (size_t)2);
}
HeapRegionRemSet::HeapRegionRemSet(G1BlockOffsetSharedArray* bosa,
HeapRegion* hr)
: _bosa(bosa), _other_regions(hr),
_outgoing_region_map(G1CollectedHeap::heap()->max_regions(),
false /* in-resource-area */),
_iter_state(Unclaimed)
{}
void HeapRegionRemSet::init_for_par_iteration() {
_iter_state = Unclaimed;
}
bool HeapRegionRemSet::claim_iter() {
if (_iter_state != Unclaimed) return false;
jint res = Atomic::cmpxchg(Claimed, (jint*)(&_iter_state), Unclaimed);
return (res == Unclaimed);
}
void HeapRegionRemSet::set_iter_complete() {
_iter_state = Complete;
}
bool HeapRegionRemSet::iter_is_complete() {
return _iter_state == Complete;
}
void HeapRegionRemSet::init_iterator(HeapRegionRemSetIterator* iter) const {
iter->initialize(this);
}
#ifndef PRODUCT
void HeapRegionRemSet::print() const {
HeapRegionRemSetIterator iter;
init_iterator(&iter);
size_t card_index;
while (iter.has_next(card_index)) {
HeapWord* card_start =
G1CollectedHeap::heap()->bot_shared()->address_for_index(card_index);
gclog_or_tty->print_cr(" Card " PTR_FORMAT ".", card_start);
}
// XXX
if (iter.n_yielded() != occupied()) {
gclog_or_tty->print_cr("Yielded disagrees with occupied:");
gclog_or_tty->print_cr(" %6d yielded (%6d coarse, %6d fine).",
iter.n_yielded(),
iter.n_yielded_coarse(), iter.n_yielded_fine());
gclog_or_tty->print_cr(" %6d occ (%6d coarse, %6d fine).",
occupied(), occ_coarse(), occ_fine());
}
guarantee(iter.n_yielded() == occupied(),
"We should have yielded all the represented cards.");
}
#endif
void HeapRegionRemSet::cleanup() {
SparsePRT::cleanup_all();
}
void HeapRegionRemSet::par_cleanup() {
PosParPRT::par_contract_all();
}
void HeapRegionRemSet::add_outgoing_reference(HeapRegion* to_hr) {
_outgoing_region_map.par_at_put(to_hr->hrs_index(), 1);
}
void HeapRegionRemSet::clear() {
clear_outgoing_entries();
_outgoing_region_map.clear();
_other_regions.clear();
assert(occupied() == 0, "Should be clear.");
}
void HeapRegionRemSet::clear_outgoing_entries() {
G1CollectedHeap* g1h = G1CollectedHeap::heap();
size_t i = _outgoing_region_map.get_next_one_offset(0);
while (i < _outgoing_region_map.size()) {
HeapRegion* to_region = g1h->region_at(i);
to_region->rem_set()->clear_incoming_entry(hr());
i = _outgoing_region_map.get_next_one_offset(i+1);
}
}
void HeapRegionRemSet::scrub(CardTableModRefBS* ctbs,
BitMap* region_bm, BitMap* card_bm) {
_other_regions.scrub(ctbs, region_bm, card_bm);
}
//-------------------- Iteration --------------------
HeapRegionRemSetIterator::
HeapRegionRemSetIterator() :
_hrrs(NULL),
_g1h(G1CollectedHeap::heap()),
_bosa(NULL),
_sparse_iter(size_t(G1CollectedHeap::heap()->reserved_region().start())
>> CardTableModRefBS::card_shift)
{}
void HeapRegionRemSetIterator::initialize(const HeapRegionRemSet* hrrs) {
_hrrs = hrrs;
_coarse_map = &_hrrs->_other_regions._coarse_map;
_fine_grain_regions = _hrrs->_other_regions._fine_grain_regions;
_bosa = _hrrs->bosa();
_is = Sparse;
// Set these values so that we increment to the first region.
_coarse_cur_region_index = -1;
_coarse_cur_region_cur_card = (PosParPRT::CardsPerRegion-1);;
_cur_region_cur_card = 0;
_fine_array_index = -1;
_fine_cur_prt = NULL;
_n_yielded_coarse = 0;
_n_yielded_fine = 0;
_n_yielded_sparse = 0;
_sparse_iter.init(&hrrs->_other_regions._sparse_table);
}
bool HeapRegionRemSetIterator::coarse_has_next(size_t& card_index) {
if (_hrrs->_other_regions._n_coarse_entries == 0) return false;
// Go to the next card.
_coarse_cur_region_cur_card++;
// Was the last the last card in the current region?
if (_coarse_cur_region_cur_card == PosParPRT::CardsPerRegion) {
// Yes: find the next region. This may leave _coarse_cur_region_index
// Set to the last index, in which case there are no more coarse
// regions.
_coarse_cur_region_index =
(int) _coarse_map->get_next_one_offset(_coarse_cur_region_index + 1);
if ((size_t)_coarse_cur_region_index < _coarse_map->size()) {
_coarse_cur_region_cur_card = 0;
HeapWord* r_bot =
_g1h->region_at(_coarse_cur_region_index)->bottom();
_cur_region_card_offset = _bosa->index_for(r_bot);
} else {
return false;
}
}
// If we didn't return false above, then we can yield a card.
card_index = _cur_region_card_offset + _coarse_cur_region_cur_card;
return true;
}
void HeapRegionRemSetIterator::fine_find_next_non_null_prt() {
// Otherwise, find the next bucket list in the array.
_fine_array_index++;
while (_fine_array_index < (int) OtherRegionsTable::_max_fine_entries) {
_fine_cur_prt = _fine_grain_regions[_fine_array_index];
if (_fine_cur_prt != NULL) return;
else _fine_array_index++;
}
assert(_fine_cur_prt == NULL, "Loop post");
}
bool HeapRegionRemSetIterator::fine_has_next(size_t& card_index) {
if (fine_has_next()) {
_cur_region_cur_card =
_fine_cur_prt->_bm.get_next_one_offset(_cur_region_cur_card + 1);
}
while (!fine_has_next()) {
if (_cur_region_cur_card == PosParPRT::CardsPerRegion) {
_cur_region_cur_card = 0;
_fine_cur_prt = _fine_cur_prt->next();
}
if (_fine_cur_prt == NULL) {
fine_find_next_non_null_prt();
if (_fine_cur_prt == NULL) return false;
}
assert(_fine_cur_prt != NULL && _cur_region_cur_card == 0,
"inv.");
HeapWord* r_bot =
_fine_cur_prt->hr()->bottom();
_cur_region_card_offset = _bosa->index_for(r_bot);
_cur_region_cur_card = _fine_cur_prt->_bm.get_next_one_offset(0);
}
assert(fine_has_next(), "Or else we exited the loop via the return.");
card_index = _cur_region_card_offset + _cur_region_cur_card;
return true;
}
bool HeapRegionRemSetIterator::fine_has_next() {
return
_fine_cur_prt != NULL &&
_cur_region_cur_card < PosParPRT::CardsPerRegion;
}
bool HeapRegionRemSetIterator::has_next(size_t& card_index) {
switch (_is) {
case Sparse:
if (_sparse_iter.has_next(card_index)) {
_n_yielded_sparse++;
return true;
}
// Otherwise, deliberate fall-through
_is = Fine;
case Fine:
if (fine_has_next(card_index)) {
_n_yielded_fine++;
return true;
}
// Otherwise, deliberate fall-through
_is = Coarse;
case Coarse:
if (coarse_has_next(card_index)) {
_n_yielded_coarse++;
return true;
}
// Otherwise...
break;
}
assert(ParallelGCThreads > 1 ||
n_yielded() == _hrrs->occupied(),
"Should have yielded all the cards in the rem set "
"(in the non-par case).");
return false;
}
oop** HeapRegionRemSet::_recorded_oops = NULL;
HeapWord** HeapRegionRemSet::_recorded_cards = NULL;
HeapRegion** HeapRegionRemSet::_recorded_regions = NULL;
int HeapRegionRemSet::_n_recorded = 0;
HeapRegionRemSet::Event* HeapRegionRemSet::_recorded_events = NULL;
int* HeapRegionRemSet::_recorded_event_index = NULL;
int HeapRegionRemSet::_n_recorded_events = 0;
void HeapRegionRemSet::record(HeapRegion* hr, oop* f) {
if (_recorded_oops == NULL) {
assert(_n_recorded == 0
&& _recorded_cards == NULL
&& _recorded_regions == NULL,
"Inv");
_recorded_oops = NEW_C_HEAP_ARRAY(oop*, MaxRecorded);
_recorded_cards = NEW_C_HEAP_ARRAY(HeapWord*, MaxRecorded);
_recorded_regions = NEW_C_HEAP_ARRAY(HeapRegion*, MaxRecorded);
}
if (_n_recorded == MaxRecorded) {
gclog_or_tty->print_cr("Filled up 'recorded' (%d).", MaxRecorded);
} else {
_recorded_cards[_n_recorded] =
(HeapWord*)align_size_down(uintptr_t(f),
CardTableModRefBS::card_size);
_recorded_oops[_n_recorded] = f;
_recorded_regions[_n_recorded] = hr;
_n_recorded++;
}
}
void HeapRegionRemSet::record_event(Event evnt) {
if (!G1RecordHRRSEvents) return;
if (_recorded_events == NULL) {
assert(_n_recorded_events == 0
&& _recorded_event_index == NULL,
"Inv");
_recorded_events = NEW_C_HEAP_ARRAY(Event, MaxRecordedEvents);
_recorded_event_index = NEW_C_HEAP_ARRAY(int, MaxRecordedEvents);
}
if (_n_recorded_events == MaxRecordedEvents) {
gclog_or_tty->print_cr("Filled up 'recorded_events' (%d).", MaxRecordedEvents);
} else {
_recorded_events[_n_recorded_events] = evnt;
_recorded_event_index[_n_recorded_events] = _n_recorded;
_n_recorded_events++;
}
}
void HeapRegionRemSet::print_event(outputStream* str, Event evnt) {
switch (evnt) {
case Event_EvacStart:
str->print("Evac Start");
break;
case Event_EvacEnd:
str->print("Evac End");
break;
case Event_RSUpdateEnd:
str->print("RS Update End");
break;
}
}
void HeapRegionRemSet::print_recorded() {
int cur_evnt = 0;
Event cur_evnt_kind;
int cur_evnt_ind = 0;
if (_n_recorded_events > 0) {
cur_evnt_kind = _recorded_events[cur_evnt];
cur_evnt_ind = _recorded_event_index[cur_evnt];
}
for (int i = 0; i < _n_recorded; i++) {
while (cur_evnt < _n_recorded_events && i == cur_evnt_ind) {
gclog_or_tty->print("Event: ");
print_event(gclog_or_tty, cur_evnt_kind);
gclog_or_tty->print_cr("");
cur_evnt++;
if (cur_evnt < MaxRecordedEvents) {
cur_evnt_kind = _recorded_events[cur_evnt];
cur_evnt_ind = _recorded_event_index[cur_evnt];
}
}
gclog_or_tty->print("Added card " PTR_FORMAT " to region [" PTR_FORMAT "...]"
" for ref " PTR_FORMAT ".\n",
_recorded_cards[i], _recorded_regions[i]->bottom(),
_recorded_oops[i]);
}
}
#ifndef PRODUCT
void HeapRegionRemSet::test() {
os::sleep(Thread::current(), (jlong)5000, false);
G1CollectedHeap* g1h = G1CollectedHeap::heap();
// Run with "-XX:G1LogRSRegionEntries=2", so that 1 and 5 end up in same
// hash bucket.
HeapRegion* hr0 = g1h->region_at(0);
HeapRegion* hr1 = g1h->region_at(1);
HeapRegion* hr2 = g1h->region_at(5);
HeapRegion* hr3 = g1h->region_at(6);
HeapRegion* hr4 = g1h->region_at(7);
HeapRegion* hr5 = g1h->region_at(8);
HeapWord* hr1_start = hr1->bottom();
HeapWord* hr1_mid = hr1_start + HeapRegion::GrainWords/2;
HeapWord* hr1_last = hr1->end() - 1;
HeapWord* hr2_start = hr2->bottom();
HeapWord* hr2_mid = hr2_start + HeapRegion::GrainWords/2;
HeapWord* hr2_last = hr2->end() - 1;
HeapWord* hr3_start = hr3->bottom();
HeapWord* hr3_mid = hr3_start + HeapRegion::GrainWords/2;
HeapWord* hr3_last = hr3->end() - 1;
HeapRegionRemSet* hrrs = hr0->rem_set();
// Make three references from region 0x101...
hrrs->add_reference((oop*)hr1_start);
hrrs->add_reference((oop*)hr1_mid);
hrrs->add_reference((oop*)hr1_last);
hrrs->add_reference((oop*)hr2_start);
hrrs->add_reference((oop*)hr2_mid);
hrrs->add_reference((oop*)hr2_last);
hrrs->add_reference((oop*)hr3_start);
hrrs->add_reference((oop*)hr3_mid);
hrrs->add_reference((oop*)hr3_last);
// Now cause a coarsening.
hrrs->add_reference((oop*)hr4->bottom());
hrrs->add_reference((oop*)hr5->bottom());
// Now, does iteration yield these three?
HeapRegionRemSetIterator iter;
hrrs->init_iterator(&iter);
size_t sum = 0;
size_t card_index;
while (iter.has_next(card_index)) {
HeapWord* card_start =
G1CollectedHeap::heap()->bot_shared()->address_for_index(card_index);
gclog_or_tty->print_cr(" Card " PTR_FORMAT ".", card_start);
sum++;
}
guarantee(sum == 11 - 3 + 2048, "Failure");
guarantee(sum == hrrs->occupied(), "Failure");
}
#endif
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