Mon, 26 Jan 2009 12:47:21 -0800
6786503: Overflow list performance can be improved
Summary: Avoid overflow list walk in CMS & ParNew when it is unnecessary. Fix a couple of correctness issues, including a C-heap leak, in ParNew at the intersection of promotion failure, work queue overflow and object array chunking. Add stress testing option and related assertion checking.
Reviewed-by: jmasa
1 /*
2 * Copyright 2001-2008 Sun Microsystems, Inc. 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
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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).
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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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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23 */
25 inline OopsInGenClosure::OopsInGenClosure(Generation* gen) :
26 OopClosure(gen->ref_processor()), _orig_gen(gen), _rs(NULL) {
27 set_generation(gen);
28 }
30 inline void OopsInGenClosure::set_generation(Generation* gen) {
31 _gen = gen;
32 _gen_boundary = _gen->reserved().start();
33 // Barrier set for the heap, must be set after heap is initialized
34 if (_rs == NULL) {
35 GenRemSet* rs = SharedHeap::heap()->rem_set();
36 assert(rs->rs_kind() == GenRemSet::CardTable, "Wrong rem set kind");
37 _rs = (CardTableRS*)rs;
38 }
39 }
41 template <class T> inline void OopsInGenClosure::do_barrier(T* p) {
42 assert(generation()->is_in_reserved(p), "expected ref in generation");
43 assert(!oopDesc::is_null(*p), "expected non-null object");
44 oop obj = oopDesc::load_decode_heap_oop_not_null(p);
45 // If p points to a younger generation, mark the card.
46 if ((HeapWord*)obj < _gen_boundary) {
47 _rs->inline_write_ref_field_gc(p, obj);
48 }
49 }
51 inline void OopsInGenClosure::par_do_barrier(oop* p) {
52 assert(generation()->is_in_reserved(p), "expected ref in generation");
53 oop obj = *p;
54 assert(obj != NULL, "expected non-null object");
55 // If p points to a younger generation, mark the card.
56 if ((HeapWord*)obj < gen_boundary()) {
57 rs()->write_ref_field_gc_par(p, obj);
58 }
59 }
61 // NOTE! Any changes made here should also be made
62 // in FastScanClosure::do_oop_work()
63 template <class T> inline void ScanClosure::do_oop_work(T* p) {
64 T heap_oop = oopDesc::load_heap_oop(p);
65 // Should we copy the obj?
66 if (!oopDesc::is_null(heap_oop)) {
67 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
68 if ((HeapWord*)obj < _boundary) {
69 assert(!_g->to()->is_in_reserved(obj), "Scanning field twice?");
70 oop new_obj = obj->is_forwarded() ? obj->forwardee()
71 : _g->copy_to_survivor_space(obj);
72 oopDesc::encode_store_heap_oop_not_null(p, new_obj);
73 }
74 if (_gc_barrier) {
75 // Now call parent closure
76 do_barrier(p);
77 }
78 }
79 }
81 inline void ScanClosure::do_oop_nv(oop* p) { ScanClosure::do_oop_work(p); }
82 inline void ScanClosure::do_oop_nv(narrowOop* p) { ScanClosure::do_oop_work(p); }
84 // NOTE! Any changes made here should also be made
85 // in ScanClosure::do_oop_work()
86 template <class T> inline void FastScanClosure::do_oop_work(T* p) {
87 T heap_oop = oopDesc::load_heap_oop(p);
88 // Should we copy the obj?
89 if (!oopDesc::is_null(heap_oop)) {
90 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
91 if ((HeapWord*)obj < _boundary) {
92 assert(!_g->to()->is_in_reserved(obj), "Scanning field twice?");
93 oop new_obj = obj->is_forwarded() ? obj->forwardee()
94 : _g->copy_to_survivor_space(obj);
95 oopDesc::encode_store_heap_oop_not_null(p, new_obj);
96 if (_gc_barrier) {
97 // Now call parent closure
98 do_barrier(p);
99 }
100 }
101 }
102 }
104 inline void FastScanClosure::do_oop_nv(oop* p) { FastScanClosure::do_oop_work(p); }
105 inline void FastScanClosure::do_oop_nv(narrowOop* p) { FastScanClosure::do_oop_work(p); }
107 // Note similarity to ScanClosure; the difference is that
108 // the barrier set is taken care of outside this closure.
109 template <class T> inline void ScanWeakRefClosure::do_oop_work(T* p) {
110 assert(!oopDesc::is_null(*p), "null weak reference?");
111 oop obj = oopDesc::load_decode_heap_oop_not_null(p);
112 // weak references are sometimes scanned twice; must check
113 // that to-space doesn't already contain this object
114 if ((HeapWord*)obj < _boundary && !_g->to()->is_in_reserved(obj)) {
115 oop new_obj = obj->is_forwarded() ? obj->forwardee()
116 : _g->copy_to_survivor_space(obj);
117 oopDesc::encode_store_heap_oop_not_null(p, new_obj);
118 }
119 }
121 inline void ScanWeakRefClosure::do_oop_nv(oop* p) { ScanWeakRefClosure::do_oop_work(p); }
122 inline void ScanWeakRefClosure::do_oop_nv(narrowOop* p) { ScanWeakRefClosure::do_oop_work(p); }