Mon, 07 Jul 2014 10:12:40 +0200
8049421: G1 Class Unloading after completing a concurrent mark cycle
Reviewed-by: tschatzl, ehelin, brutisso, coleenp, roland, iveresov
Contributed-by: stefan.karlsson@oracle.com, mikael.gerdin@oracle.com
1 /*
2 * Copyright (c) 2001, 2014, 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.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1OOPCLOSURES_INLINE_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1OOPCLOSURES_INLINE_HPP
28 #include "gc_implementation/g1/concurrentMark.inline.hpp"
29 #include "gc_implementation/g1/g1CollectedHeap.hpp"
30 #include "gc_implementation/g1/g1OopClosures.hpp"
31 #include "gc_implementation/g1/g1ParScanThreadState.inline.hpp"
32 #include "gc_implementation/g1/g1RemSet.hpp"
33 #include "gc_implementation/g1/g1RemSet.inline.hpp"
34 #include "gc_implementation/g1/heapRegionRemSet.hpp"
35 #include "memory/iterator.inline.hpp"
36 #include "runtime/prefetch.inline.hpp"
38 /*
39 * This really ought to be an inline function, but apparently the C++
40 * compiler sometimes sees fit to ignore inline declarations. Sigh.
41 */
43 template <class T>
44 inline void FilterIntoCSClosure::do_oop_nv(T* p) {
45 T heap_oop = oopDesc::load_heap_oop(p);
46 if (!oopDesc::is_null(heap_oop) &&
47 _g1->obj_in_cs(oopDesc::decode_heap_oop_not_null(heap_oop))) {
48 _oc->do_oop(p);
49 }
50 }
52 template <class T>
53 inline void FilterOutOfRegionClosure::do_oop_nv(T* p) {
54 T heap_oop = oopDesc::load_heap_oop(p);
55 if (!oopDesc::is_null(heap_oop)) {
56 HeapWord* obj_hw = (HeapWord*)oopDesc::decode_heap_oop_not_null(heap_oop);
57 if (obj_hw < _r_bottom || obj_hw >= _r_end) {
58 _oc->do_oop(p);
59 }
60 }
61 }
63 // This closure is applied to the fields of the objects that have just been copied.
64 template <class T>
65 inline void G1ParScanClosure::do_oop_nv(T* p) {
66 T heap_oop = oopDesc::load_heap_oop(p);
68 if (!oopDesc::is_null(heap_oop)) {
69 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
70 if (_g1->in_cset_fast_test(obj)) {
71 // We're not going to even bother checking whether the object is
72 // already forwarded or not, as this usually causes an immediate
73 // stall. We'll try to prefetch the object (for write, given that
74 // we might need to install the forwarding reference) and we'll
75 // get back to it when pop it from the queue
76 Prefetch::write(obj->mark_addr(), 0);
77 Prefetch::read(obj->mark_addr(), (HeapWordSize*2));
79 // slightly paranoid test; I'm trying to catch potential
80 // problems before we go into push_on_queue to know where the
81 // problem is coming from
82 assert((obj == oopDesc::load_decode_heap_oop(p)) ||
83 (obj->is_forwarded() &&
84 obj->forwardee() == oopDesc::load_decode_heap_oop(p)),
85 "p should still be pointing to obj or to its forwardee");
87 _par_scan_state->push_on_queue(p);
88 } else {
89 _par_scan_state->update_rs(_from, p, _worker_id);
90 }
91 }
92 }
94 template <class T>
95 inline void G1ParPushHeapRSClosure::do_oop_nv(T* p) {
96 T heap_oop = oopDesc::load_heap_oop(p);
98 if (!oopDesc::is_null(heap_oop)) {
99 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
100 if (_g1->in_cset_fast_test(obj)) {
101 Prefetch::write(obj->mark_addr(), 0);
102 Prefetch::read(obj->mark_addr(), (HeapWordSize*2));
104 // Place on the references queue
105 _par_scan_state->push_on_queue(p);
106 }
107 }
108 }
110 template <class T>
111 inline void G1CMOopClosure::do_oop_nv(T* p) {
112 oop obj = oopDesc::load_decode_heap_oop(p);
113 if (_cm->verbose_high()) {
114 gclog_or_tty->print_cr("[%u] we're looking at location "
115 "*"PTR_FORMAT" = "PTR_FORMAT,
116 _task->worker_id(), p2i(p), p2i((void*) obj));
117 }
118 _task->deal_with_reference(obj);
119 }
121 template <class T>
122 inline void G1RootRegionScanClosure::do_oop_nv(T* p) {
123 T heap_oop = oopDesc::load_heap_oop(p);
124 if (!oopDesc::is_null(heap_oop)) {
125 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
126 HeapRegion* hr = _g1h->heap_region_containing((HeapWord*) obj);
127 if (hr != NULL) {
128 _cm->grayRoot(obj, obj->size(), _worker_id, hr);
129 }
130 }
131 }
133 template <class T>
134 inline void G1Mux2Closure::do_oop_nv(T* p) {
135 // Apply first closure; then apply the second.
136 _c1->do_oop(p);
137 _c2->do_oop(p);
138 }
140 template <class T>
141 inline void G1TriggerClosure::do_oop_nv(T* p) {
142 // Record that this closure was actually applied (triggered).
143 _triggered = true;
144 }
146 template <class T>
147 inline void G1InvokeIfNotTriggeredClosure::do_oop_nv(T* p) {
148 if (!_trigger_cl->triggered()) {
149 _oop_cl->do_oop(p);
150 }
151 }
153 template <class T>
154 inline void G1UpdateRSOrPushRefOopClosure::do_oop_nv(T* p) {
155 oop obj = oopDesc::load_decode_heap_oop(p);
156 #ifdef ASSERT
157 // can't do because of races
158 // assert(obj == NULL || obj->is_oop(), "expected an oop");
160 // Do the safe subset of is_oop
161 if (obj != NULL) {
162 #ifdef CHECK_UNHANDLED_OOPS
163 oopDesc* o = obj.obj();
164 #else
165 oopDesc* o = obj;
166 #endif // CHECK_UNHANDLED_OOPS
167 assert((intptr_t)o % MinObjAlignmentInBytes == 0, "not oop aligned");
168 assert(Universe::heap()->is_in_reserved(obj), "must be in heap");
169 }
170 #endif // ASSERT
172 assert(_from != NULL, "from region must be non-NULL");
173 assert(_from->is_in_reserved(p), "p is not in from");
175 HeapRegion* to = _g1->heap_region_containing(obj);
176 if (to != NULL && _from != to) {
177 // The _record_refs_into_cset flag is true during the RSet
178 // updating part of an evacuation pause. It is false at all
179 // other times:
180 // * rebuilding the rembered sets after a full GC
181 // * during concurrent refinement.
182 // * updating the remembered sets of regions in the collection
183 // set in the event of an evacuation failure (when deferred
184 // updates are enabled).
186 if (_record_refs_into_cset && to->in_collection_set()) {
187 // We are recording references that point into the collection
188 // set and this particular reference does exactly that...
189 // If the referenced object has already been forwarded
190 // to itself, we are handling an evacuation failure and
191 // we have already visited/tried to copy this object
192 // there is no need to retry.
193 if (!self_forwarded(obj)) {
194 assert(_push_ref_cl != NULL, "should not be null");
195 // Push the reference in the refs queue of the G1ParScanThreadState
196 // instance for this worker thread.
197 _push_ref_cl->do_oop(p);
198 }
200 // Deferred updates to the CSet are either discarded (in the normal case),
201 // or processed (if an evacuation failure occurs) at the end
202 // of the collection.
203 // See G1RemSet::cleanup_after_oops_into_collection_set_do().
204 return;
205 }
207 // We either don't care about pushing references that point into the
208 // collection set (i.e. we're not during an evacuation pause) _or_
209 // the reference doesn't point into the collection set. Either way
210 // we add the reference directly to the RSet of the region containing
211 // the referenced object.
212 assert(to->rem_set() != NULL, "Need per-region 'into' remsets.");
213 to->rem_set()->add_reference(p, _worker_i);
214 }
215 }
217 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1OOPCLOSURES_INLINE_HPP