Java example source code file (heapRegionRemSet.cpp)
The heapRegionRemSet.cpp Java example source code/*
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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
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*
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* 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).
*
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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_implementation/g1/concurrentG1Refine.hpp"
#include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp"
#include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
#include "gc_implementation/g1/heapRegionRemSet.hpp"
#include "gc_implementation/g1/heapRegionSeq.inline.hpp"
#include "memory/allocation.hpp"
#include "memory/space.inline.hpp"
#include "oops/oop.inline.hpp"
#include "utilities/bitMap.inline.hpp"
#include "utilities/globalDefinitions.hpp"
#include "utilities/growableArray.hpp"
class PerRegionTable: public CHeapObj<mtGC> {
friend class OtherRegionsTable;
friend class HeapRegionRemSetIterator;
HeapRegion* _hr;
BitMap _bm;
jint _occupied;
// next pointer for free/allocated 'all' list
PerRegionTable* _next;
// prev pointer for the allocated 'all' list
PerRegionTable* _prev;
// next pointer in collision list
PerRegionTable * _collision_list_next;
// Global free list of PRTs
static PerRegionTable* _free_list;
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),
_occupied(0),
_bm(HeapRegion::CardsPerRegion, false /* in-resource-area */),
_collision_list_next(NULL), _next(NULL), _prev(NULL)
{}
void add_card_work(CardIdx_t from_card, bool par) {
if (!_bm.at(from_card)) {
if (par) {
if (_bm.par_at_put(from_card, 1)) {
Atomic::inc(&_occupied);
}
} else {
_bm.at_put(from_card, 1);
_occupied++;
}
}
}
void add_reference_work(OopOrNarrowOopStar from, bool par) {
// Must make this robust in case "from" is not in "_hr", because of
// concurrency.
if (G1TraceHeapRegionRememberedSet) {
gclog_or_tty->print_cr(" PRT::Add_reference_work(" PTR_FORMAT "->" PTR_FORMAT").",
from,
UseCompressedOops
? (void *)oopDesc::load_decode_heap_oop((narrowOop*)from)
: (void *)oopDesc::load_decode_heap_oop((oop*)from));
}
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 the table used to belong to a continues humongous region and is
// now reused for the corresponding start humongous region, we need to
// make sure that we detect this. Thus, we call is_in_reserved_raw()
// instead of just is_in_reserved() here.
if (loc_hr->is_in_reserved_raw(from)) {
size_t hw_offset = pointer_delta((HeapWord*)from, loc_hr->bottom());
CardIdx_t from_card = (CardIdx_t)
hw_offset >> (CardTableModRefBS::card_shift - LogHeapWordSize);
assert(0 <= from_card && (size_t)from_card < HeapRegion::CardsPerRegion,
"Must be in range.");
add_card_work(from_card, par);
}
}
public:
HeapRegion* hr() const { return _hr; }
jint occupied() const {
// Overkill, but if we ever need it...
// guarantee(_occupied == _bm.count_one_bits(), "Check");
return _occupied;
}
void init(HeapRegion* hr, bool clear_links_to_all_list) {
if (clear_links_to_all_list) {
set_next(NULL);
set_prev(NULL);
}
_hr = hr;
_collision_list_next = NULL;
_occupied = 0;
_bm.clear();
}
void add_reference(OopOrNarrowOopStar from) {
add_reference_work(from, /*parallel*/ true);
}
void seq_add_reference(OopOrNarrowOopStar from) {
add_reference_work(from, /*parallel*/ false);
}
void scrub(CardTableModRefBS* ctbs, BitMap* card_bm) {
HeapWord* hr_bot = hr()->bottom();
size_t hr_first_card_index = ctbs->index_for(hr_bot);
bm()->set_intersection_at_offset(*card_bm, hr_first_card_index);
recount_occupied();
}
void add_card(CardIdx_t from_card_index) {
add_card_work(from_card_index, /*parallel*/ true);
}
void seq_add_card(CardIdx_t 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;
}
// Requires "from" to be in "hr()".
bool contains_reference(OopOrNarrowOopStar 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);
}
// Bulk-free the PRTs from prt to last, assumes that they are
// linked together using their _next field.
static void bulk_free(PerRegionTable* prt, PerRegionTable* last) {
while (true) {
PerRegionTable* fl = _free_list;
last->set_next(fl);
PerRegionTable* res = (PerRegionTable*) Atomic::cmpxchg_ptr(prt, &_free_list, fl);
if (res == fl) {
return;
}
}
ShouldNotReachHere();
}
static void free(PerRegionTable* prt) {
bulk_free(prt, prt);
}
// Returns an initialized PerRegionTable instance.
static PerRegionTable* alloc(HeapRegion* hr) {
PerRegionTable* fl = _free_list;
while (fl != NULL) {
PerRegionTable* nxt = fl->next();
PerRegionTable* res =
(PerRegionTable*)
Atomic::cmpxchg_ptr(nxt, &_free_list, fl);
if (res == fl) {
fl->init(hr, true);
return fl;
} else {
fl = _free_list;
}
}
assert(fl == NULL, "Loop condition.");
return new PerRegionTable(hr);
}
PerRegionTable* next() const { return _next; }
void set_next(PerRegionTable* next) { _next = next; }
PerRegionTable* prev() const { return _prev; }
void set_prev(PerRegionTable* prev) { _prev = prev; }
// Accessor and Modification routines for the pointer for the
// singly linked collision list that links the PRTs within the
// OtherRegionsTable::_fine_grain_regions hash table.
//
// It might be useful to also make the collision list doubly linked
// to avoid iteration over the collisions list during scrubbing/deletion.
// OTOH there might not be many collisions.
PerRegionTable* collision_list_next() const {
return _collision_list_next;
}
void set_collision_list_next(PerRegionTable* next) {
_collision_list_next = next;
}
PerRegionTable** collision_list_next_addr() {
return &_collision_list_next;
}
static size_t fl_mem_size() {
PerRegionTable* cur = _free_list;
size_t res = 0;
while (cur != NULL) {
res += cur->mem_size();
cur = cur->next();
}
return res;
}
static void test_fl_mem_size();
};
PerRegionTable* PerRegionTable::_free_list = NULL;
size_t OtherRegionsTable::_max_fine_entries = 0;
size_t OtherRegionsTable::_mod_max_fine_entries_mask = 0;
size_t OtherRegionsTable::_fine_eviction_stride = 0;
size_t OtherRegionsTable::_fine_eviction_sample_size = 0;
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),
_first_all_fine_prts(NULL), _last_all_fine_prts(NULL),
_n_fine_entries(0), _n_coarse_entries(0),
_fine_eviction_start(0),
_sparse_table(hr)
{
typedef PerRegionTable* PerRegionTablePtr;
if (_max_fine_entries == 0) {
assert(_mod_max_fine_entries_mask == 0, "Both or none.");
size_t max_entries_log = (size_t)log2_long((jlong)G1RSetRegionEntries);
_max_fine_entries = (size_t)1 << max_entries_log;
_mod_max_fine_entries_mask = _max_fine_entries - 1;
assert(_fine_eviction_sample_size == 0
&& _fine_eviction_stride == 0, "All init at same time.");
_fine_eviction_sample_size = MAX2((size_t)4, max_entries_log);
_fine_eviction_stride = _max_fine_entries / _fine_eviction_sample_size;
}
_fine_grain_regions = NEW_C_HEAP_ARRAY3(PerRegionTablePtr, _max_fine_entries,
mtGC, 0, AllocFailStrategy::RETURN_NULL);
if (_fine_grain_regions == NULL) {
vm_exit_out_of_memory(sizeof(void*)*_max_fine_entries, OOM_MALLOC_ERROR,
"Failed to allocate _fine_grain_entries.");
}
for (size_t i = 0; i < _max_fine_entries; i++) {
_fine_grain_regions[i] = NULL;
}
}
void OtherRegionsTable::link_to_all(PerRegionTable* prt) {
// We always append to the beginning of the list for convenience;
// the order of entries in this list does not matter.
if (_first_all_fine_prts != NULL) {
assert(_first_all_fine_prts->prev() == NULL, "invariant");
_first_all_fine_prts->set_prev(prt);
prt->set_next(_first_all_fine_prts);
} else {
// this is the first element we insert. Adjust the "last" pointer
_last_all_fine_prts = prt;
assert(prt->next() == NULL, "just checking");
}
// the new element is always the first element without a predecessor
prt->set_prev(NULL);
_first_all_fine_prts = prt;
assert(prt->prev() == NULL, "just checking");
assert(_first_all_fine_prts == prt, "just checking");
assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) ||
(_first_all_fine_prts != NULL && _last_all_fine_prts != NULL),
"just checking");
assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL,
"just checking");
assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL,
"just checking");
}
void OtherRegionsTable::unlink_from_all(PerRegionTable* prt) {
if (prt->prev() != NULL) {
assert(_first_all_fine_prts != prt, "just checking");
prt->prev()->set_next(prt->next());
// removing the last element in the list?
if (_last_all_fine_prts == prt) {
_last_all_fine_prts = prt->prev();
}
} else {
assert(_first_all_fine_prts == prt, "just checking");
_first_all_fine_prts = prt->next();
// list is empty now?
if (_first_all_fine_prts == NULL) {
_last_all_fine_prts = NULL;
}
}
if (prt->next() != NULL) {
prt->next()->set_prev(prt->prev());
}
prt->set_next(NULL);
prt->set_prev(NULL);
assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) ||
(_first_all_fine_prts != NULL && _last_all_fine_prts != NULL),
"just checking");
assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL,
"just checking");
assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL,
"just checking");
}
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, mtGC);
for (int i = 0; i < n_par_rs; i++) {
_from_card_cache[i] = NEW_C_HEAP_ARRAY(int, max_regions, mtGC);
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(OopOrNarrowOopStar from, int tid) {
size_t cur_hrs_ind = (size_t) hr()->hrs_index();
if (G1TraceHeapRegionRememberedSet) {
gclog_or_tty->print_cr("ORT::add_reference_work(" PTR_FORMAT "->" PTR_FORMAT ").",
from,
UseCompressedOops
? (void *)oopDesc::load_decode_heap_oop((narrowOop*)from)
: (void *)oopDesc::load_decode_heap_oop((oop*)from));
}
int from_card = (int)(uintptr_t(from) >> CardTableModRefBS::card_shift);
if (G1TraceHeapRegionRememberedSet) {
gclog_or_tty->print_cr("Table for [" PTR_FORMAT "...): card %d (cache = %d)",
hr()->bottom(), from_card,
_from_card_cache[tid][cur_hrs_ind]);
}
if (from_card == _from_card_cache[tid][cur_hrs_ind]) {
if (G1TraceHeapRegionRememberedSet) {
gclog_or_tty->print_cr(" from-card cache hit.");
}
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);
RegionIdx_t from_hrs_ind = (RegionIdx_t) from_hr->hrs_index();
// If the region is already coarsened, return.
if (_coarse_map.at(from_hrs_ind)) {
if (G1TraceHeapRegionRememberedSet) {
gclog_or_tty->print_cr(" coarse map hit.");
}
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;
PerRegionTable* 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;
CardIdx_t card_index = from_card - from_hr_bot_card_index;
assert(0 <= card_index && (size_t)card_index < HeapRegion::CardsPerRegion,
"Must be in range.");
if (G1HRRSUseSparseTable &&
_sparse_table.add_card(from_hrs_ind, card_index)) {
if (G1RecordHRRSOops) {
HeapRegionRemSet::record(hr(), from);
if (G1TraceHeapRegionRememberedSet) {
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);
}
}
if (G1TraceHeapRegionRememberedSet) {
gclog_or_tty->print_cr(" added card to sparse table.");
}
assert(contains_reference_locked(from), "We just added it!");
return;
} else {
if (G1TraceHeapRegionRememberedSet) {
gclog_or_tty->print_cr(" [tid %d] sparse table entry "
"overflow(f: %d, t: %d)",
tid, from_hrs_ind, cur_hrs_ind);
}
}
if (_n_fine_entries == _max_fine_entries) {
prt = delete_region_table();
// There is no need to clear the links to the 'all' list here:
// prt will be reused immediately, i.e. remain in the 'all' list.
prt->init(from_hr, false /* clear_links_to_all_list */);
} else {
prt = PerRegionTable::alloc(from_hr);
link_to_all(prt);
}
PerRegionTable* first_prt = _fine_grain_regions[ind];
prt->set_collision_list_next(first_prt);
_fine_grain_regions[ind] = prt;
_n_fine_entries++;
if (G1HRRSUseSparseTable) {
// Transfer from sparse to fine-grain.
SparsePRTEntry *sprt_entry = _sparse_table.get_entry(from_hrs_ind);
assert(sprt_entry != NULL, "There should have been an entry");
for (int i = 0; i < SparsePRTEntry::cards_num(); i++) {
CardIdx_t c = sprt_entry->card(i);
if (c != SparsePRTEntry::NullEntry) {
prt->add_card(c);
}
}
// Now we can delete the sparse entry.
bool res = _sparse_table.delete_entry(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);
if (G1RecordHRRSOops) {
HeapRegionRemSet::record(hr(), from);
if (G1TraceHeapRegionRememberedSet) {
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);
}
}
assert(contains_reference(from), "We just added it!");
}
PerRegionTable*
OtherRegionsTable::find_region_table(size_t ind, HeapRegion* hr) const {
assert(0 <= ind && ind < _max_fine_entries, "Preconditions.");
PerRegionTable* prt = _fine_grain_regions[ind];
while (prt != NULL && prt->hr() != hr) {
prt = prt->collision_list_next();
}
// Loop postcondition is the method postcondition.
return prt;
}
jint OtherRegionsTable::_n_coarsenings = 0;
PerRegionTable* OtherRegionsTable::delete_region_table() {
assert(_m.owned_by_self(), "Precondition");
assert(_n_fine_entries == _max_fine_entries, "Precondition");
PerRegionTable* max = NULL;
jint max_occ = 0;
PerRegionTable** max_prev;
size_t max_ind;
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.");
}
PerRegionTable** prev = &_fine_grain_regions[ii];
PerRegionTable* 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->collision_list_next_addr();
cur = cur->collision_list_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;
}
guarantee(max != NULL, "Since _n_fine_entries > 0");
// Set the corresponding coarse bit.
size_t max_hrs_index = (size_t) max->hr()->hrs_index();
if (!_coarse_map.at(max_hrs_index)) {
_coarse_map.at_put(max_hrs_index, true);
_n_coarse_entries++;
if (G1TraceHeapRegionRememberedSet) {
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);
}
}
// Unsplice.
*max_prev = max->collision_list_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 %u:", hr()->hrs_index());
}
assert(_coarse_map.size() == region_bm->size(), "Precondition");
if (G1RSScrubVerbose) {
gclog_or_tty->print(" Coarse map: before = "SIZE_FORMAT"...",
_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 = "SIZE_FORMAT".", _n_coarse_entries);
}
// Now do the fine-grained maps.
for (size_t i = 0; i < _max_fine_entries; i++) {
PerRegionTable* cur = _fine_grain_regions[i];
PerRegionTable** prev = &_fine_grain_regions[i];
while (cur != NULL) {
PerRegionTable* nxt = cur->collision_list_next();
// If the entire region is dead, eliminate.
if (G1RSScrubVerbose) {
gclog_or_tty->print_cr(" For other region %u:",
cur->hr()->hrs_index());
}
if (!region_bm->at((size_t) cur->hr()->hrs_index())) {
*prev = nxt;
cur->set_collision_list_next(NULL);
_n_fine_entries--;
if (G1RSScrubVerbose) {
gclog_or_tty->print_cr(" deleted via region map.");
}
unlink_from_all(cur);
PerRegionTable::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_collision_list_next(NULL);
_n_fine_entries--;
unlink_from_all(cur);
PerRegionTable::free(cur);
} else {
prev = cur->collision_list_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;
size_t num = 0;
PerRegionTable * cur = _first_all_fine_prts;
while (cur != NULL) {
sum += cur->occupied();
cur = cur->next();
num++;
}
guarantee(num == _n_fine_entries, "just checking");
return sum;
}
size_t OtherRegionsTable::occ_coarse() const {
return (_n_coarse_entries * HeapRegion::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;
// all PRTs are of the same size so it is sufficient to query only one of them.
if (_first_all_fine_prts != NULL) {
assert(_last_all_fine_prts != NULL &&
_first_all_fine_prts->mem_size() == _last_all_fine_prts->mem_size(), "check that mem_size() is constant");
sum += _first_all_fine_prts->mem_size() * _n_fine_entries;
}
sum += (sizeof(PerRegionTable*) * _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();
}
void OtherRegionsTable::clear_fcc() {
size_t hrs_idx = hr()->hrs_index();
for (int i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
_from_card_cache[i][hrs_idx] = -1;
}
}
void OtherRegionsTable::clear() {
MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag);
// if there are no entries, skip this step
if (_first_all_fine_prts != NULL) {
guarantee(_first_all_fine_prts != NULL && _last_all_fine_prts != NULL, "just checking");
PerRegionTable::bulk_free(_first_all_fine_prts, _last_all_fine_prts);
memset(_fine_grain_regions, 0, _max_fine_entries * sizeof(_fine_grain_regions[0]));
} else {
guarantee(_first_all_fine_prts == NULL && _last_all_fine_prts == NULL, "just checking");
}
_first_all_fine_prts = _last_all_fine_prts = 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.
size_t hr_ind = (size_t) 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.");
PerRegionTable** prev_addr = &_fine_grain_regions[ind];
PerRegionTable* prt = *prev_addr;
while (prt != NULL && prt->hr() != hr) {
prev_addr = prt->collision_list_next_addr();
prt = prt->collision_list_next();
}
if (prt != NULL) {
assert(prt->hr() == hr, "Loop postcondition.");
*prev_addr = prt->collision_list_next();
unlink_from_all(prt);
PerRegionTable::free(prt);
_n_fine_entries--;
return true;
} else {
return false;
}
}
bool OtherRegionsTable::contains_reference(OopOrNarrowOopStar 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(OopOrNarrowOopStar from) const {
HeapRegion* hr = _g1h->heap_region_containing_raw(from);
if (hr == NULL) return false;
RegionIdx_t hr_ind = (RegionIdx_t) hr->hrs_index();
// Is this region in the coarse map?
if (_coarse_map.at(hr_ind)) return true;
PerRegionTable* 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");
CardIdx_t card_index = from_card - hr_bot_card_index;
assert(0 <= card_index && (size_t)card_index < HeapRegion::CardsPerRegion,
"Must be in range.");
return _sparse_table.contains_card(hr_ind, card_index);
}
}
void
OtherRegionsTable::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) {
_sparse_table.do_cleanup_work(hrrs_cleanup_task);
}
// Determines how many threads can add records to an rset in parallel.
// This can be done by either mutator threads together with the
// concurrent refinement threads or GC threads.
int HeapRegionRemSet::num_par_rem_sets() {
return (int)MAX2(DirtyCardQueueSet::num_par_ids() + ConcurrentG1Refine::thread_num(), ParallelGCThreads);
}
HeapRegionRemSet::HeapRegionRemSet(G1BlockOffsetSharedArray* bosa,
HeapRegion* hr)
: _bosa(bosa), _strong_code_roots_list(NULL), _other_regions(hr) {
reset_for_par_iteration();
}
void HeapRegionRemSet::setup_remset_size() {
// Setup sparse and fine-grain tables sizes.
// table_size = base * (log(region_size / 1M) + 1)
const int LOG_M = 20;
int region_size_log_mb = MAX2(HeapRegion::LogOfHRGrainBytes - LOG_M, 0);
if (FLAG_IS_DEFAULT(G1RSetSparseRegionEntries)) {
G1RSetSparseRegionEntries = G1RSetSparseRegionEntriesBase * (region_size_log_mb + 1);
}
if (FLAG_IS_DEFAULT(G1RSetRegionEntries)) {
G1RSetRegionEntries = G1RSetRegionEntriesBase * (region_size_log_mb + 1);
}
guarantee(G1RSetSparseRegionEntries > 0 && G1RSetRegionEntries > 0 , "Sanity");
}
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;
}
#ifndef PRODUCT
void HeapRegionRemSet::print() const {
HeapRegionRemSetIterator iter(this);
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);
}
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::clear() {
if (_strong_code_roots_list != NULL) {
delete _strong_code_roots_list;
}
_strong_code_roots_list = new (ResourceObj::C_HEAP, mtGC)
GrowableArray<nmethod*>(10, 0, NULL, true);
_other_regions.clear();
assert(occupied() == 0, "Should be clear.");
reset_for_par_iteration();
}
void HeapRegionRemSet::reset_for_par_iteration() {
_iter_state = Unclaimed;
_iter_claimed = 0;
// It's good to check this to make sure that the two methods are in sync.
assert(verify_ready_for_par_iteration(), "post-condition");
}
void HeapRegionRemSet::scrub(CardTableModRefBS* ctbs,
BitMap* region_bm, BitMap* card_bm) {
_other_regions.scrub(ctbs, region_bm, card_bm);
}
// Code roots support
void HeapRegionRemSet::add_strong_code_root(nmethod* nm) {
assert(nm != NULL, "sanity");
// Search for the code blob from the RHS to avoid
// duplicate entries as much as possible
if (_strong_code_roots_list->find_from_end(nm) < 0) {
// Code blob isn't already in the list
_strong_code_roots_list->push(nm);
}
}
void HeapRegionRemSet::remove_strong_code_root(nmethod* nm) {
assert(nm != NULL, "sanity");
int idx = _strong_code_roots_list->find(nm);
if (idx >= 0) {
_strong_code_roots_list->remove_at(idx);
}
// Check that there were no duplicates
guarantee(_strong_code_roots_list->find(nm) < 0, "duplicate entry found");
}
class NMethodMigrationOopClosure : public OopClosure {
G1CollectedHeap* _g1h;
HeapRegion* _from;
nmethod* _nm;
uint _num_self_forwarded;
template <class T> void do_oop_work(T* p) {
T heap_oop = oopDesc::load_heap_oop(p);
if (!oopDesc::is_null(heap_oop)) {
oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
if (_from->is_in(obj)) {
// Reference still points into the source region.
// Since roots are immediately evacuated this means that
// we must have self forwarded the object
assert(obj->is_forwarded(),
err_msg("code roots should be immediately evacuated. "
"Ref: "PTR_FORMAT", "
"Obj: "PTR_FORMAT", "
"Region: "HR_FORMAT,
p, (void*) obj, HR_FORMAT_PARAMS(_from)));
assert(obj->forwardee() == obj,
err_msg("not self forwarded? obj = "PTR_FORMAT, (void*)obj));
// The object has been self forwarded.
// Note, if we're during an initial mark pause, there is
// no need to explicitly mark object. It will be marked
// during the regular evacuation failure handling code.
_num_self_forwarded++;
} else {
// The reference points into a promotion or to-space region
HeapRegion* to = _g1h->heap_region_containing(obj);
to->rem_set()->add_strong_code_root(_nm);
}
}
}
public:
NMethodMigrationOopClosure(G1CollectedHeap* g1h, HeapRegion* from, nmethod* nm):
_g1h(g1h), _from(from), _nm(nm), _num_self_forwarded(0) {}
void do_oop(narrowOop* p) { do_oop_work(p); }
void do_oop(oop* p) { do_oop_work(p); }
uint retain() { return _num_self_forwarded > 0; }
};
void HeapRegionRemSet::migrate_strong_code_roots() {
assert(hr()->in_collection_set(), "only collection set regions");
assert(!hr()->isHumongous(),
err_msg("humongous region "HR_FORMAT" should not have been added to the collection set",
HR_FORMAT_PARAMS(hr())));
ResourceMark rm;
// List of code blobs to retain for this region
GrowableArray<nmethod*> to_be_retained(10);
G1CollectedHeap* g1h = G1CollectedHeap::heap();
while (_strong_code_roots_list->is_nonempty()) {
nmethod *nm = _strong_code_roots_list->pop();
if (nm != NULL) {
NMethodMigrationOopClosure oop_cl(g1h, hr(), nm);
nm->oops_do(&oop_cl);
if (oop_cl.retain()) {
to_be_retained.push(nm);
}
}
}
// Now push any code roots we need to retain
assert(to_be_retained.is_empty() || hr()->evacuation_failed(),
"Retained nmethod list must be empty or "
"evacuation of this region failed");
while (to_be_retained.is_nonempty()) {
nmethod* nm = to_be_retained.pop();
assert(nm != NULL, "sanity");
add_strong_code_root(nm);
}
}
void HeapRegionRemSet::strong_code_roots_do(CodeBlobClosure* blk) const {
for (int i = 0; i < _strong_code_roots_list->length(); i += 1) {
nmethod* nm = _strong_code_roots_list->at(i);
blk->do_code_blob(nm);
}
}
size_t HeapRegionRemSet::strong_code_roots_mem_size() {
return sizeof(GrowableArray<nmethod*>) +
_strong_code_roots_list->max_length() * sizeof(nmethod*);
}
//-------------------- Iteration --------------------
HeapRegionRemSetIterator:: HeapRegionRemSetIterator(const HeapRegionRemSet* hrrs) :
_hrrs(hrrs),
_g1h(G1CollectedHeap::heap()),
_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(HeapRegion::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(&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 == HeapRegion::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((uint) _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 == (size_t) HeapRegion::CardsPerRegion) {
_cur_region_cur_card = 0;
_fine_cur_prt = _fine_cur_prt->collision_list_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 < HeapRegion::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;
}
OopOrNarrowOopStar* 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, OopOrNarrowOopStar f) {
if (_recorded_oops == NULL) {
assert(_n_recorded == 0
&& _recorded_cards == NULL
&& _recorded_regions == NULL,
"Inv");
_recorded_oops = NEW_C_HEAP_ARRAY(OopOrNarrowOopStar, MaxRecorded, mtGC);
_recorded_cards = NEW_C_HEAP_ARRAY(HeapWord*, MaxRecorded, mtGC);
_recorded_regions = NEW_C_HEAP_ARRAY(HeapRegion*, MaxRecorded, mtGC);
}
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, mtGC);
_recorded_event_index = NEW_C_HEAP_ARRAY(int, MaxRecordedEvents, mtGC);
}
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]);
}
}
void HeapRegionRemSet::reset_for_cleanup_tasks() {
SparsePRT::reset_for_cleanup_tasks();
}
void HeapRegionRemSet::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) {
_other_regions.do_cleanup_work(hrrs_cleanup_task);
}
void
HeapRegionRemSet::finish_cleanup_task(HRRSCleanupTask* hrrs_cleanup_task) {
SparsePRT::finish_cleanup_task(hrrs_cleanup_task);
}
#ifndef PRODUCT
void PerRegionTable::test_fl_mem_size() {
PerRegionTable* dummy = alloc(NULL);
free(dummy);
guarantee(dummy->mem_size() == fl_mem_size(), "fl_mem_size() does not return the correct element size");
// try to reset the state
_free_list = NULL;
delete dummy;
}
void HeapRegionRemSet::test_prt() {
PerRegionTable::test_fl_mem_size();
}
void HeapRegionRemSet::test() {
os::sleep(Thread::current(), (jlong)5000, false);
G1CollectedHeap* g1h = G1CollectedHeap::heap();
// Run with "-XX:G1LogRSetRegionEntries=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((OopOrNarrowOopStar)hr1_start);
hrrs->add_reference((OopOrNarrowOopStar)hr1_mid);
hrrs->add_reference((OopOrNarrowOopStar)hr1_last);
hrrs->add_reference((OopOrNarrowOopStar)hr2_start);
hrrs->add_reference((OopOrNarrowOopStar)hr2_mid);
hrrs->add_reference((OopOrNarrowOopStar)hr2_last);
hrrs->add_reference((OopOrNarrowOopStar)hr3_start);
hrrs->add_reference((OopOrNarrowOopStar)hr3_mid);
hrrs->add_reference((OopOrNarrowOopStar)hr3_last);
// Now cause a coarsening.
hrrs->add_reference((OopOrNarrowOopStar)hr4->bottom());
hrrs->add_reference((OopOrNarrowOopStar)hr5->bottom());
// Now, does iteration yield these three?
HeapRegionRemSetIterator iter(hrrs);
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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