1 /*
2 * Copyright (c) 2001, 2016, 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 */
24
25 #ifndef SHARE_VM_GC_G1_HEAPREGION_INLINE_HPP
26 #define SHARE_VM_GC_G1_HEAPREGION_INLINE_HPP
27
28 #include "gc/g1/g1BlockOffsetTable.inline.hpp"
29 #include "gc/g1/g1CollectedHeap.inline.hpp"
30 #include "gc/g1/heapRegion.hpp"
31 #include "gc/shared/space.hpp"
32 #include "oops/oop.inline.hpp"
33 #include "runtime/atomic.hpp"
34
35 inline HeapWord* G1ContiguousSpace::allocate_impl(size_t min_word_size,
36 size_t desired_word_size,
37 size_t* actual_size) {
38 HeapWord* obj = top();
39 size_t available = pointer_delta(end(), obj);
40 size_t want_to_allocate = MIN2(available, desired_word_size);
41 if (want_to_allocate >= min_word_size) {
42 HeapWord* new_top = obj + want_to_allocate;
43 set_top(new_top);
44 assert(is_aligned(obj) && is_aligned(new_top), "checking alignment");
45 *actual_size = want_to_allocate;
46 return obj;
47 } else {
48 return NULL;
49 }
50 }
51
52 inline HeapWord* G1ContiguousSpace::par_allocate_impl(size_t min_word_size,
53 size_t desired_word_size,
54 size_t* actual_size) {
55 do {
56 HeapWord* obj = top();
57 size_t available = pointer_delta(end(), obj);
58 size_t want_to_allocate = MIN2(available, desired_word_size);
59 if (want_to_allocate >= min_word_size) {
60 HeapWord* new_top = obj + want_to_allocate;
61 HeapWord* result = (HeapWord*)Atomic::cmpxchg_ptr(new_top, top_addr(), obj);
62 // result can be one of two:
63 // the old top value: the exchange succeeded
64 // otherwise: the new value of the top is returned.
65 if (result == obj) {
66 assert(is_aligned(obj) && is_aligned(new_top), "checking alignment");
67 *actual_size = want_to_allocate;
68 return obj;
69 }
70 } else {
71 return NULL;
72 }
73 } while (true);
74 }
75
76 inline HeapWord* G1ContiguousSpace::allocate(size_t min_word_size,
77 size_t desired_word_size,
78 size_t* actual_size) {
79 HeapWord* res = allocate_impl(min_word_size, desired_word_size, actual_size);
80 if (res != NULL) {
81 _bot_part.alloc_block(res, *actual_size);
82 }
83 return res;
84 }
85
86 inline HeapWord* G1ContiguousSpace::allocate(size_t word_size) {
87 size_t temp;
88 return allocate(word_size, word_size, &temp);
89 }
90
91 inline HeapWord* G1ContiguousSpace::par_allocate(size_t word_size) {
92 size_t temp;
93 return par_allocate(word_size, word_size, &temp);
94 }
95
96 // Because of the requirement of keeping "_offsets" up to date with the
97 // allocations, we sequentialize these with a lock. Therefore, best if
98 // this is used for larger LAB allocations only.
99 inline HeapWord* G1ContiguousSpace::par_allocate(size_t min_word_size,
100 size_t desired_word_size,
101 size_t* actual_size) {
102 MutexLocker x(&_par_alloc_lock);
103 return allocate(min_word_size, desired_word_size, actual_size);
104 }
105
106 inline HeapWord* G1ContiguousSpace::block_start(const void* p) {
107 return _bot_part.block_start(p);
108 }
109
110 inline HeapWord*
111 G1ContiguousSpace::block_start_const(const void* p) const {
112 return _bot_part.block_start_const(p);
113 }
114
115 inline bool
116 HeapRegion::block_is_obj(const HeapWord* p) const {
117 G1CollectedHeap* g1h = G1CollectedHeap::heap();
118
119 if (!this->is_in(p)) {
120 assert(is_continues_humongous(), "This case can only happen for humongous regions");
121 return (p == humongous_start_region()->bottom());
122 }
123 if (ClassUnloadingWithConcurrentMark) {
124 return !g1h->is_obj_dead(oop(p), this);
125 }
126 return p < top();
127 }
128
129 inline size_t
130 HeapRegion::block_size(const HeapWord *addr) const {
131 if (addr == top()) {
132 return pointer_delta(end(), addr);
133 }
134
135 if (block_is_obj(addr)) {
136 return oop(addr)->size();
137 }
138
139 assert(ClassUnloadingWithConcurrentMark,
140 "All blocks should be objects if G1 Class Unloading isn't used. "
141 "HR: [" PTR_FORMAT ", " PTR_FORMAT ", " PTR_FORMAT ") "
142 "addr: " PTR_FORMAT,
143 p2i(bottom()), p2i(top()), p2i(end()), p2i(addr));
144
145 // Old regions' dead objects may have dead classes
146 // We need to find the next live object in some other
147 // manner than getting the oop size
148 G1CollectedHeap* g1h = G1CollectedHeap::heap();
149 HeapWord* next = g1h->concurrent_mark()->prevMarkBitMap()->
150 getNextMarkedWordAddress(addr, prev_top_at_mark_start());
151
152 assert(next > addr, "must get the next live object");
153 return pointer_delta(next, addr);
154 }
155
156 inline HeapWord* HeapRegion::par_allocate_no_bot_updates(size_t min_word_size,
157 size_t desired_word_size,
158 size_t* actual_word_size) {
159 assert(is_young(), "we can only skip BOT updates on young regions");
160 return par_allocate_impl(min_word_size, desired_word_size, actual_word_size);
161 }
162
163 inline HeapWord* HeapRegion::allocate_no_bot_updates(size_t word_size) {
164 size_t temp;
165 return allocate_no_bot_updates(word_size, word_size, &temp);
166 }
167
168 inline HeapWord* HeapRegion::allocate_no_bot_updates(size_t min_word_size,
169 size_t desired_word_size,
170 size_t* actual_word_size) {
171 assert(is_young(), "we can only skip BOT updates on young regions");
172 return allocate_impl(min_word_size, desired_word_size, actual_word_size);
173 }
174
175 inline void HeapRegion::note_start_of_marking() {
176 _next_marked_bytes = 0;
177 _next_top_at_mark_start = top();
178 }
179
180 inline void HeapRegion::note_end_of_marking() {
181 _prev_top_at_mark_start = _next_top_at_mark_start;
182 _prev_marked_bytes = _next_marked_bytes;
183 _next_marked_bytes = 0;
184 }
185
186 inline void HeapRegion::note_start_of_copying(bool during_initial_mark) {
187 if (is_survivor()) {
188 // This is how we always allocate survivors.
189 assert(_next_top_at_mark_start == bottom(), "invariant");
190 } else {
191 if (during_initial_mark) {
192 // During initial-mark we'll explicitly mark any objects on old
193 // regions that are pointed to by roots. Given that explicit
194 // marks only make sense under NTAMS it'd be nice if we could
195 // check that condition if we wanted to. Given that we don't
196 // know where the top of this region will end up, we simply set
197 // NTAMS to the end of the region so all marks will be below
198 // NTAMS. We'll set it to the actual top when we retire this region.
199 _next_top_at_mark_start = end();
200 } else {
201 // We could have re-used this old region as to-space over a
202 // couple of GCs since the start of the concurrent marking
203 // cycle. This means that [bottom,NTAMS) will contain objects
204 // copied up to and including initial-mark and [NTAMS, top)
205 // will contain objects copied during the concurrent marking cycle.
206 assert(top() >= _next_top_at_mark_start, "invariant");
207 }
208 }
209 }
210
211 inline void HeapRegion::note_end_of_copying(bool during_initial_mark) {
212 if (is_survivor()) {
213 // This is how we always allocate survivors.
214 assert(_next_top_at_mark_start == bottom(), "invariant");
215 } else {
216 if (during_initial_mark) {
217 // See the comment for note_start_of_copying() for the details
218 // on this.
219 assert(_next_top_at_mark_start == end(), "pre-condition");
220 _next_top_at_mark_start = top();
221 } else {
222 // See the comment for note_start_of_copying() for the details
223 // on this.
224 assert(top() >= _next_top_at_mark_start, "invariant");
225 }
226 }
227 }
228
229 inline bool HeapRegion::in_collection_set() const {
230 return G1CollectedHeap::heap()->is_in_cset(this);
231 }
232
233 #endif // SHARE_VM_GC_G1_HEAPREGION_INLINE_HPP