1 /*
2 * Copyright (c) 2015, Red Hat, Inc. and/or its affiliates.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #ifndef SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEAP_INLINE_HPP
25 #define SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEAP_INLINE_HPP
26
27 #include "gc/shared/cmBitMap.inline.hpp"
28 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
29 #include "gc/shenandoah/shenandoahHeap.hpp"
30 #include "runtime/atomic.inline.hpp"
31
32 /*
33 * Marks the object. Returns true if the object has not been marked before and has
34 * been marked by this thread. Returns false if the object has already been marked,
35 * or if a competing thread succeeded in marking this object.
36 */
37 inline bool ShenandoahHeap::mark_current(oop obj) const {
38 #ifdef ASSERT
39 if (obj != oopDesc::bs()->read_barrier(obj)) {
40 tty->print_cr("heap region containing obj:");
41 ShenandoahHeapRegion* obj_region = heap_region_containing(obj);
42 obj_region->print();
43 tty->print_cr("heap region containing forwardee:");
44 ShenandoahHeapRegion* forward_region = heap_region_containing(oopDesc::bs()->read_barrier(obj));
45 forward_region->print();
46 }
47 #endif
48
49 assert(obj == oopDesc::bs()->read_barrier(obj), "only mark forwarded copy of objects");
50 return mark_current_no_checks(obj);
51 }
52
53 inline bool ShenandoahHeap::mark_current_no_checks(oop obj) const {
54 return _next_mark_bit_map->parMark((HeapWord*) obj);
55 }
56
57 inline bool ShenandoahHeap::is_marked_current(oop obj) const {
58 return _next_mark_bit_map->isMarked((HeapWord*) obj);
59 }
60
61 inline bool ShenandoahHeap::need_update_refs() const {
62 return _need_update_refs;
63 }
64
65 inline uint ShenandoahHeap::heap_region_index_containing(const void* addr) const {
66 uintptr_t region_start = ((uintptr_t) addr); // & ~(ShenandoahHeapRegion::RegionSizeBytes - 1);
67 uintptr_t index = (region_start - (uintptr_t) _first_region_bottom) >> ShenandoahHeapRegion::RegionSizeShift;
68 #ifdef ASSERT
69 if (!(index < _num_regions)) {
70 tty->print_cr("heap region does not contain address, first_region_bottom: "PTR_FORMAT", real bottom of first region: "PTR_FORMAT", num_regions: "SIZE_FORMAT", region_size: "SIZE_FORMAT, p2i(_first_region_bottom), p2i(_ordered_regions[0]->bottom()), _num_regions, ShenandoahHeapRegion::RegionSizeBytes);
71 }
72 #endif
73 assert(index < _num_regions, "heap region index must be in range");
74 return index;
75 }
76
77 oop ShenandoahHeap::maybe_update_oop_ref(oop* p) {
78
79 assert((! is_in(p)) || (! heap_region_containing(p)->is_in_collection_set()),
80 "never update refs in from-space, unless evacuation has been cancelled");
81
82 oop heap_oop = oopDesc::load_heap_oop(p); // read p
83 if (! oopDesc::is_null(heap_oop)) {
84
85 #ifdef ASSERT
86 if (! is_in(heap_oop)) {
87 print_heap_regions();
88 tty->print_cr("object not in heap: "PTR_FORMAT", referenced by: "PTR_FORMAT, p2i((HeapWord*) heap_oop), p2i(p));
89 assert(is_in(heap_oop), "object must be in heap");
90 }
91 #endif
92 assert(is_in(heap_oop), "only ever call this on objects in the heap");
93 assert((! (is_in(p) && heap_region_containing(p)->is_in_collection_set())), "we don't want to update references in from-space");
94 oop forwarded_oop = ShenandoahBarrierSet::resolve_oop_static_not_null(heap_oop); // read brooks ptr
95 if (forwarded_oop != heap_oop) {
96 // tty->print_cr("updating old ref: "PTR_FORMAT" pointing to "PTR_FORMAT" to new ref: "PTR_FORMAT, p2i(p), p2i(heap_oop), p2i(forwarded_oop));
97 assert(forwarded_oop->is_oop(), "oop required");
98 assert(is_in(forwarded_oop), "forwardee must be in heap");
99 assert(! heap_region_containing(forwarded_oop)->is_in_collection_set(), "forwardee must not be in collection set");
100 // If this fails, another thread wrote to p before us, it will be logged in SATB and the
101 // reference be updated later.
102 oop result = (oop) Atomic::cmpxchg_ptr(forwarded_oop, p, heap_oop);
103
104 if (result == heap_oop) { // CAS successful.
105 return forwarded_oop;
106 } else {
107 return result;
108 }
109 } else {
110 return forwarded_oop;
111 }
112 /*
113 else {
114 tty->print_cr("not updating ref: "PTR_FORMAT, p2i(heap_oop));
115 }
116 */
117 }
118 return NULL;
119 }
120
121 #endif // SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEAP_INLINE_HPP