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/*
* Copyright (c) 2014, 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 "code/codeCache.hpp"
#include "code/nmethod.hpp"
#include "gc_implementation/g1/g1CodeCacheRemSet.hpp"
#include "gc_implementation/g1/heapRegion.hpp"
#include "memory/heap.hpp"
#include "memory/iterator.hpp"
#include "oops/oop.inline.hpp"
#include "utilities/hashtable.inline.hpp"
#include "utilities/stack.inline.hpp"
PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
class CodeRootSetTable : public Hashtable<nmethod*, mtGC> {
friend class G1CodeRootSetTest;
typedef HashtableEntry<nmethod*, mtGC> Entry;
static CodeRootSetTable* volatile _purge_list;
CodeRootSetTable* _purge_next;
unsigned int compute_hash(nmethod* nm) {
uintptr_t hash = (uintptr_t)nm;
return hash ^ (hash >> 7); // code heap blocks are 128byte aligned
}
void remove_entry(Entry* e, Entry* previous);
Entry* new_entry(nmethod* nm);
public:
CodeRootSetTable(int size) : Hashtable<nmethod*, mtGC>(size, sizeof(Entry)), _purge_next(NULL) {}
~CodeRootSetTable();
// Needs to be protected locks
bool add(nmethod* nm);
bool remove(nmethod* nm);
// Can be called without locking
bool contains(nmethod* nm);
int entry_size() const { return BasicHashtable<mtGC>::entry_size(); }
void copy_to(CodeRootSetTable* new_table);
void nmethods_do(CodeBlobClosure* blk);
template<typename CB>
int remove_if(CB& should_remove);
static void purge_list_append(CodeRootSetTable* tbl);
static void purge();
static size_t static_mem_size() {
return sizeof(_purge_list);
}
};
CodeRootSetTable* volatile CodeRootSetTable::_purge_list = NULL;
CodeRootSetTable::Entry* CodeRootSetTable::new_entry(nmethod* nm) {
unsigned int hash = compute_hash(nm);
Entry* entry = (Entry*) new_entry_free_list();
if (entry == NULL) {
entry = (Entry*) NEW_C_HEAP_ARRAY2(char, entry_size(), mtGC, CURRENT_PC);
}
entry->set_next(NULL);
entry->set_hash(hash);
entry->set_literal(nm);
return entry;
}
void CodeRootSetTable::remove_entry(Entry* e, Entry* previous) {
int index = hash_to_index(e->hash());
assert((e == bucket(index)) == (previous == NULL), "if e is the first entry then previous should be null");
if (previous == NULL) {
set_entry(index, e->next());
} else {
previous->set_next(e->next());
}
free_entry(e);
}
CodeRootSetTable::~CodeRootSetTable() {
for (int index = 0; index < table_size(); ++index) {
for (Entry* e = bucket(index); e != NULL; ) {
Entry* to_remove = e;
// read next before freeing.
e = e->next();
unlink_entry(to_remove);
FREE_C_HEAP_ARRAY(char, to_remove, mtGC);
}
}
assert(number_of_entries() == 0, "should have removed all entries");
free_buckets();
for (BasicHashtableEntry<mtGC>* e = new_entry_free_list(); e != NULL; e = new_entry_free_list()) {
FREE_C_HEAP_ARRAY(char, e, mtGC);
}
}
bool CodeRootSetTable::add(nmethod* nm) {
if (!contains(nm)) {
Entry* e = new_entry(nm);
int index = hash_to_index(e->hash());
add_entry(index, e);
return true;
}
return false;
}
bool CodeRootSetTable::contains(nmethod* nm) {
int index = hash_to_index(compute_hash(nm));
for (Entry* e = bucket(index); e != NULL; e = e->next()) {
if (e->literal() == nm) {
return true;
}
}
return false;
}
bool CodeRootSetTable::remove(nmethod* nm) {
int index = hash_to_index(compute_hash(nm));
Entry* previous = NULL;
for (Entry* e = bucket(index); e != NULL; previous = e, e = e->next()) {
if (e->literal() == nm) {
remove_entry(e, previous);
return true;
}
}
return false;
}
void CodeRootSetTable::copy_to(CodeRootSetTable* new_table) {
for (int index = 0; index < table_size(); ++index) {
for (Entry* e = bucket(index); e != NULL; e = e->next()) {
new_table->add(e->literal());
}
}
new_table->copy_freelist(this);
}
void CodeRootSetTable::nmethods_do(CodeBlobClosure* blk) {
for (int index = 0; index < table_size(); ++index) {
for (Entry* e = bucket(index); e != NULL; e = e->next()) {
blk->do_code_blob(e->literal());
}
}
}
template<typename CB>
int CodeRootSetTable::remove_if(CB& should_remove) {
int num_removed = 0;
for (int index = 0; index < table_size(); ++index) {
Entry* previous = NULL;
Entry* e = bucket(index);
while (e != NULL) {
Entry* next = e->next();
if (should_remove(e->literal())) {
remove_entry(e, previous);
++num_removed;
} else {
previous = e;
}
e = next;
}
}
return num_removed;
}
G1CodeRootSet::~G1CodeRootSet() {
delete _table;
}
CodeRootSetTable* G1CodeRootSet::load_acquire_table() {
return (CodeRootSetTable*) OrderAccess::load_ptr_acquire(&_table);
}
void G1CodeRootSet::allocate_small_table() {
_table = new CodeRootSetTable(SmallSize);
}
void CodeRootSetTable::purge_list_append(CodeRootSetTable* table) {
for (;;) {
table->_purge_next = _purge_list;
CodeRootSetTable* old = (CodeRootSetTable*) Atomic::cmpxchg_ptr(table, &_purge_list, table->_purge_next);
if (old == table->_purge_next) {
break;
}
}
}
void CodeRootSetTable::purge() {
CodeRootSetTable* table = _purge_list;
_purge_list = NULL;
while (table != NULL) {
CodeRootSetTable* to_purge = table;
table = table->_purge_next;
delete to_purge;
}
}
void G1CodeRootSet::move_to_large() {
CodeRootSetTable* temp = new CodeRootSetTable(LargeSize);
_table->copy_to(temp);
CodeRootSetTable::purge_list_append(_table);
OrderAccess::release_store_ptr(&_table, temp);
}
void G1CodeRootSet::purge() {
CodeRootSetTable::purge();
}
size_t G1CodeRootSet::static_mem_size() {
return CodeRootSetTable::static_mem_size();
}
void G1CodeRootSet::add(nmethod* method) {
bool added = false;
if (is_empty()) {
allocate_small_table();
}
added = _table->add(method);
if (_length == Threshold) {
move_to_large();
}
if (added) {
++_length;
}
}
bool G1CodeRootSet::remove(nmethod* method) {
bool removed = false;
if (_table != NULL) {
removed = _table->remove(method);
}
if (removed) {
_length--;
if (_length == 0) {
clear();
}
}
return removed;
}
bool G1CodeRootSet::contains(nmethod* method) {
CodeRootSetTable* table = load_acquire_table();
if (table != NULL) {
return table->contains(method);
}
return false;
}
void G1CodeRootSet::clear() {
delete _table;
_table = NULL;
_length = 0;
}
size_t G1CodeRootSet::mem_size() {
return sizeof(*this) +
(_table != NULL ? sizeof(CodeRootSetTable) + _table->entry_size() * _length : 0);
}
void G1CodeRootSet::nmethods_do(CodeBlobClosure* blk) const {
if (_table != NULL) {
_table->nmethods_do(blk);
}
}
class CleanCallback : public StackObj {
class PointsIntoHRDetectionClosure : public OopClosure {
HeapRegion* _hr;
public:
bool _points_into;
PointsIntoHRDetectionClosure(HeapRegion* hr) : _hr(hr), _points_into(false) {}
void do_oop(narrowOop* o) {
do_oop_work(o);
}
void do_oop(oop* o) {
do_oop_work(o);
}
template <typename T>
void do_oop_work(T* p) {
if (_hr->is_in(oopDesc::load_decode_heap_oop(p))) {
_points_into = true;
}
}
};
PointsIntoHRDetectionClosure _detector;
CodeBlobToOopClosure _blobs;
public:
CleanCallback(HeapRegion* hr) : _detector(hr), _blobs(&_detector, !CodeBlobToOopClosure::FixRelocations) {}
bool operator() (nmethod* nm) {
_detector._points_into = false;
_blobs.do_code_blob(nm);
return !_detector._points_into;
}
};
void G1CodeRootSet::clean(HeapRegion* owner) {
CleanCallback should_clean(owner);
if (_table != NULL) {
int removed = _table->remove_if(should_clean);
assert((size_t)removed <= _length, "impossible");
_length -= removed;
}
if (_length == 0) {
clear();
}
}
#ifndef PRODUCT
class G1CodeRootSetTest {
public:
static void test() {
{
G1CodeRootSet set1;
assert(set1.is_empty(), "Code root set must be initially empty but is not.");
assert(G1CodeRootSet::static_mem_size() == sizeof(void*),
err_msg("The code root set's static memory usage is incorrect, "SIZE_FORMAT" bytes", G1CodeRootSet::static_mem_size()));
set1.add((nmethod*)1);
assert(set1.length() == 1, err_msg("Added exactly one element, but set contains "
SIZE_FORMAT" elements", set1.length()));
const size_t num_to_add = (size_t)G1CodeRootSet::Threshold + 1;
for (size_t i = 1; i <= num_to_add; i++) {
set1.add((nmethod*)1);
}
assert(set1.length() == 1,
err_msg("Duplicate detection should not have increased the set size but "
"is "SIZE_FORMAT, set1.length()));
for (size_t i = 2; i <= num_to_add; i++) {
set1.add((nmethod*)(uintptr_t)(i));
}
assert(set1.length() == num_to_add,
err_msg("After adding in total "SIZE_FORMAT" distinct code roots, they "
"need to be in the set, but there are only "SIZE_FORMAT,
num_to_add, set1.length()));
assert(CodeRootSetTable::_purge_list != NULL, "should have grown to large hashtable");
size_t num_popped = 0;
for (size_t i = 1; i <= num_to_add; i++) {
bool removed = set1.remove((nmethod*)i);
if (removed) {
num_popped += 1;
} else {
break;
}
}
assert(num_popped == num_to_add,
err_msg("Managed to pop "SIZE_FORMAT" code roots, but only "SIZE_FORMAT" "
"were added", num_popped, num_to_add));
assert(CodeRootSetTable::_purge_list != NULL, "should have grown to large hashtable");
G1CodeRootSet::purge();
assert(CodeRootSetTable::_purge_list == NULL, "should have purged old small tables");
}
}
};
void TestCodeCacheRemSet_test() {
G1CodeRootSetTest::test();
}
#endif