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src/share/vm/gc_implementation/parallelScavenge/psScavenge.inline.hpp@1fdb98a17101
src/share/vm/gc_implementation/parallelScavenge/psScavenge.inline.hpp
Sat, 19 Jul 2008 17:38:22 -0400
- author
- coleenp
- date
- Sat, 19 Jul 2008 17:38:22 -0400
- changeset 672
- 1fdb98a17101
- parent 631
- d1605aabd0a1
- child 1907
- c18cbe5936b8
- permissions
- -rw-r--r--
6716785: implicit null checks not triggering with CompressedOops
Summary: allocate alignment-sized page(s) below java heap so that memory accesses at heap_base+1page give signal and cause an implicit null check
Reviewed-by: kvn, jmasa, phh, jcoomes
1 /*
2 * Copyright 2002-2008 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
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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
25 inline void PSScavenge::save_to_space_top_before_gc() {
26 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
27 _to_space_top_before_gc = heap->young_gen()->to_space()->top();
28 }
30 template <class T> inline bool PSScavenge::should_scavenge(T* p) {
31 T heap_oop = oopDesc::load_heap_oop(p);
32 if (oopDesc::is_null(heap_oop)) return false;
33 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
34 return PSScavenge::is_obj_in_young((HeapWord*)obj);
35 }
37 template <class T>
38 inline bool PSScavenge::should_scavenge(T* p, MutableSpace* to_space) {
39 if (should_scavenge(p)) {
40 oop obj = oopDesc::load_decode_heap_oop_not_null(p);
41 // Skip objects copied to to_space since the scavenge started.
42 HeapWord* const addr = (HeapWord*)obj;
43 return addr < to_space_top_before_gc() || addr >= to_space->end();
44 }
45 return false;
46 }
48 template <class T>
49 inline bool PSScavenge::should_scavenge(T* p, bool check_to_space) {
50 if (check_to_space) {
51 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
52 return should_scavenge(p, heap->young_gen()->to_space());
53 }
54 return should_scavenge(p);
55 }
57 // Attempt to "claim" oop at p via CAS, push the new obj if successful
58 // This version tests the oop* to make sure it is within the heap before
59 // attempting marking.
60 template <class T>
61 inline void PSScavenge::copy_and_push_safe_barrier(PSPromotionManager* pm,
62 T* p) {
63 assert(should_scavenge(p, true), "revisiting object?");
65 oop o = oopDesc::load_decode_heap_oop_not_null(p);
66 oop new_obj = o->is_forwarded()
67 ? o->forwardee()
68 : pm->copy_to_survivor_space(o, pm->depth_first());
69 oopDesc::encode_store_heap_oop_not_null(p, new_obj);
71 // We cannot mark without test, as some code passes us pointers
72 // that are outside the heap.
73 if ((!PSScavenge::is_obj_in_young((HeapWord*)p)) &&
74 Universe::heap()->is_in_reserved(p)) {
75 if (PSScavenge::is_obj_in_young((HeapWord*)new_obj)) {
76 card_table()->inline_write_ref_field_gc(p, new_obj);
77 }
78 }
79 }
