Sat, 23 Nov 2013 12:25:13 +0100
8028128: Add a type safe alternative for working with counter based data
Reviewed-by: dholmes, egahlin
1 /*
2 * Copyright (c) 2002, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 */
25 #ifndef SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSSCAVENGE_INLINE_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSSCAVENGE_INLINE_HPP
28 #include "gc_implementation/parallelScavenge/cardTableExtension.hpp"
29 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
30 #include "gc_implementation/parallelScavenge/psPromotionManager.hpp"
31 #include "gc_implementation/parallelScavenge/psPromotionManager.inline.hpp"
32 #include "gc_implementation/parallelScavenge/psScavenge.hpp"
33 #include "memory/iterator.hpp"
35 inline void PSScavenge::save_to_space_top_before_gc() {
36 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
37 _to_space_top_before_gc = heap->young_gen()->to_space()->top();
38 }
40 template <class T> inline bool PSScavenge::should_scavenge(T* p) {
41 T heap_oop = oopDesc::load_heap_oop(p);
42 return PSScavenge::is_obj_in_young(heap_oop);
43 }
45 template <class T>
46 inline bool PSScavenge::should_scavenge(T* p, MutableSpace* to_space) {
47 if (should_scavenge(p)) {
48 oop obj = oopDesc::load_decode_heap_oop_not_null(p);
49 // Skip objects copied to to_space since the scavenge started.
50 HeapWord* const addr = (HeapWord*)obj;
51 return addr < to_space_top_before_gc() || addr >= to_space->end();
52 }
53 return false;
54 }
56 template <class T>
57 inline bool PSScavenge::should_scavenge(T* p, bool check_to_space) {
58 if (check_to_space) {
59 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
60 return should_scavenge(p, heap->young_gen()->to_space());
61 }
62 return should_scavenge(p);
63 }
65 // Attempt to "claim" oop at p via CAS, push the new obj if successful
66 // This version tests the oop* to make sure it is within the heap before
67 // attempting marking.
68 template <class T, bool promote_immediately>
69 inline void PSScavenge::copy_and_push_safe_barrier(PSPromotionManager* pm,
70 T* p) {
71 assert(should_scavenge(p, true), "revisiting object?");
73 oop o = oopDesc::load_decode_heap_oop_not_null(p);
74 oop new_obj = o->is_forwarded()
75 ? o->forwardee()
76 : pm->copy_to_survivor_space<promote_immediately>(o);
78 #ifndef PRODUCT
79 // This code must come after the CAS test, or it will print incorrect
80 // information.
81 if (TraceScavenge && o->is_forwarded()) {
82 gclog_or_tty->print_cr("{%s %s " PTR_FORMAT " -> " PTR_FORMAT " (%d)}",
83 "forwarding",
84 new_obj->klass()->internal_name(), (void *)o, (void *)new_obj, new_obj->size());
85 }
86 #endif
88 oopDesc::encode_store_heap_oop_not_null(p, new_obj);
90 // We cannot mark without test, as some code passes us pointers
91 // that are outside the heap. These pointers are either from roots
92 // or from metadata.
93 if ((!PSScavenge::is_obj_in_young((HeapWord*)p)) &&
94 Universe::heap()->is_in_reserved(p)) {
95 if (PSScavenge::is_obj_in_young(new_obj)) {
96 card_table()->inline_write_ref_field_gc(p, new_obj);
97 }
98 }
99 }
101 template<bool promote_immediately>
102 class PSRootsClosure: public OopClosure {
103 private:
104 PSPromotionManager* _promotion_manager;
106 protected:
107 template <class T> void do_oop_work(T *p) {
108 if (PSScavenge::should_scavenge(p)) {
109 // We never card mark roots, maybe call a func without test?
110 PSScavenge::copy_and_push_safe_barrier<T, promote_immediately>(_promotion_manager, p);
111 }
112 }
113 public:
114 PSRootsClosure(PSPromotionManager* pm) : _promotion_manager(pm) { }
115 void do_oop(oop* p) { PSRootsClosure::do_oop_work(p); }
116 void do_oop(narrowOop* p) { PSRootsClosure::do_oop_work(p); }
117 };
119 typedef PSRootsClosure</*promote_immediately=*/false> PSScavengeRootsClosure;
120 typedef PSRootsClosure</*promote_immediately=*/true> PSPromoteRootsClosure;
122 // Scavenges a single oop in a Klass.
123 class PSScavengeFromKlassClosure: public OopClosure {
124 private:
125 PSPromotionManager* _pm;
126 // Used to redirty a scanned klass if it has oops
127 // pointing to the young generation after being scanned.
128 Klass* _scanned_klass;
129 public:
130 PSScavengeFromKlassClosure(PSPromotionManager* pm) : _pm(pm), _scanned_klass(NULL) { }
131 void do_oop(narrowOop* p) { ShouldNotReachHere(); }
132 void do_oop(oop* p) {
133 ParallelScavengeHeap* psh = ParallelScavengeHeap::heap();
134 assert(!psh->is_in_reserved(p), "GC barrier needed");
135 if (PSScavenge::should_scavenge(p)) {
136 assert(!Universe::heap()->is_in_reserved(p), "Not from meta-data?");
137 assert(PSScavenge::should_scavenge(p, true), "revisiting object?");
139 oop o = *p;
140 oop new_obj;
141 if (o->is_forwarded()) {
142 new_obj = o->forwardee();
143 } else {
144 new_obj = _pm->copy_to_survivor_space</*promote_immediately=*/false>(o);
145 }
146 oopDesc::encode_store_heap_oop_not_null(p, new_obj);
148 if (PSScavenge::is_obj_in_young(new_obj)) {
149 do_klass_barrier();
150 }
151 }
152 }
154 void set_scanned_klass(Klass* klass) {
155 assert(_scanned_klass == NULL || klass == NULL, "Should always only handling one klass at a time");
156 _scanned_klass = klass;
157 }
159 private:
160 void do_klass_barrier() {
161 assert(_scanned_klass != NULL, "Should not be called without having a scanned klass");
162 _scanned_klass->record_modified_oops();
163 }
165 };
167 // Scavenges the oop in a Klass.
168 class PSScavengeKlassClosure: public KlassClosure {
169 private:
170 PSScavengeFromKlassClosure _oop_closure;
171 protected:
172 public:
173 PSScavengeKlassClosure(PSPromotionManager* pm) : _oop_closure(pm) { }
174 void do_klass(Klass* klass) {
175 // If the klass has not been dirtied we know that there's
176 // no references into the young gen and we can skip it.
178 #ifndef PRODUCT
179 if (TraceScavenge) {
180 ResourceMark rm;
181 gclog_or_tty->print_cr("PSScavengeKlassClosure::do_klass %p, %s, dirty: %s",
182 klass,
183 klass->external_name(),
184 klass->has_modified_oops() ? "true" : "false");
185 }
186 #endif
188 if (klass->has_modified_oops()) {
189 // Clean the klass since we're going to scavenge all the metadata.
190 klass->clear_modified_oops();
192 // Setup the promotion manager to redirty this klass
193 // if references are left in the young gen.
194 _oop_closure.set_scanned_klass(klass);
196 klass->oops_do(&_oop_closure);
198 _oop_closure.set_scanned_klass(NULL);
199 }
200 }
201 };
203 #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSSCAVENGE_INLINE_HPP