--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc/g1/g1CodeCacheRemSet.cpp Wed May 13 15:16:06 2015 +0200
@@ -0,0 +1,405 @@
+/*
+ * Copyright (c) 2014, 2015, 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/g1/g1CodeCacheRemSet.hpp"
+#include "gc/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"
+
+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);
+ }
+ }
+ 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);
+ }
+}
+
+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