Tue, 18 Mar 2014 19:07:22 +0100
8029075: String deduplication in G1
Summary: Implementation of JEP 192, http://openjdk.java.net/jeps/192
Reviewed-by: brutisso, tschatzl, coleenp
1 /*
2 * Copyright (c) 2001, 2013, 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_G1COLLECTEDHEAP_INLINE_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTEDHEAP_INLINE_HPP
28 #include "gc_implementation/g1/concurrentMark.hpp"
29 #include "gc_implementation/g1/g1CollectedHeap.hpp"
30 #include "gc_implementation/g1/g1AllocRegion.inline.hpp"
31 #include "gc_implementation/g1/g1CollectorPolicy.hpp"
32 #include "gc_implementation/g1/g1SATBCardTableModRefBS.hpp"
33 #include "gc_implementation/g1/heapRegionSet.inline.hpp"
34 #include "gc_implementation/g1/heapRegionSeq.inline.hpp"
35 #include "utilities/taskqueue.hpp"
37 // Inline functions for G1CollectedHeap
39 template <class T>
40 inline HeapRegion*
41 G1CollectedHeap::heap_region_containing(const T addr) const {
42 HeapRegion* hr = _hrs.addr_to_region((HeapWord*) addr);
43 // hr can be null if addr in perm_gen
44 if (hr != NULL && hr->continuesHumongous()) {
45 hr = hr->humongous_start_region();
46 }
47 return hr;
48 }
50 template <class T>
51 inline HeapRegion*
52 G1CollectedHeap::heap_region_containing_raw(const T addr) const {
53 assert(_g1_reserved.contains((const void*) addr), "invariant");
54 HeapRegion* res = _hrs.addr_to_region_unsafe((HeapWord*) addr);
55 return res;
56 }
58 inline bool G1CollectedHeap::obj_in_cs(oop obj) {
59 HeapRegion* r = _hrs.addr_to_region((HeapWord*) obj);
60 return r != NULL && r->in_collection_set();
61 }
63 inline HeapWord*
64 G1CollectedHeap::attempt_allocation(size_t word_size,
65 unsigned int* gc_count_before_ret,
66 int* gclocker_retry_count_ret) {
67 assert_heap_not_locked_and_not_at_safepoint();
68 assert(!isHumongous(word_size), "attempt_allocation() should not "
69 "be called for humongous allocation requests");
71 HeapWord* result = _mutator_alloc_region.attempt_allocation(word_size,
72 false /* bot_updates */);
73 if (result == NULL) {
74 result = attempt_allocation_slow(word_size,
75 gc_count_before_ret,
76 gclocker_retry_count_ret);
77 }
78 assert_heap_not_locked();
79 if (result != NULL) {
80 dirty_young_block(result, word_size);
81 }
82 return result;
83 }
85 inline HeapWord* G1CollectedHeap::survivor_attempt_allocation(size_t
86 word_size) {
87 assert(!isHumongous(word_size),
88 "we should not be seeing humongous-size allocations in this path");
90 HeapWord* result = _survivor_gc_alloc_region.attempt_allocation(word_size,
91 false /* bot_updates */);
92 if (result == NULL) {
93 MutexLockerEx x(FreeList_lock, Mutex::_no_safepoint_check_flag);
94 result = _survivor_gc_alloc_region.attempt_allocation_locked(word_size,
95 false /* bot_updates */);
96 }
97 if (result != NULL) {
98 dirty_young_block(result, word_size);
99 }
100 return result;
101 }
103 inline HeapWord* G1CollectedHeap::old_attempt_allocation(size_t word_size) {
104 assert(!isHumongous(word_size),
105 "we should not be seeing humongous-size allocations in this path");
107 HeapWord* result = _old_gc_alloc_region.attempt_allocation(word_size,
108 true /* bot_updates */);
109 if (result == NULL) {
110 MutexLockerEx x(FreeList_lock, Mutex::_no_safepoint_check_flag);
111 result = _old_gc_alloc_region.attempt_allocation_locked(word_size,
112 true /* bot_updates */);
113 }
114 return result;
115 }
117 // It dirties the cards that cover the block so that so that the post
118 // write barrier never queues anything when updating objects on this
119 // block. It is assumed (and in fact we assert) that the block
120 // belongs to a young region.
121 inline void
122 G1CollectedHeap::dirty_young_block(HeapWord* start, size_t word_size) {
123 assert_heap_not_locked();
125 // Assign the containing region to containing_hr so that we don't
126 // have to keep calling heap_region_containing_raw() in the
127 // asserts below.
128 DEBUG_ONLY(HeapRegion* containing_hr = heap_region_containing_raw(start);)
129 assert(containing_hr != NULL && start != NULL && word_size > 0,
130 "pre-condition");
131 assert(containing_hr->is_in(start), "it should contain start");
132 assert(containing_hr->is_young(), "it should be young");
133 assert(!containing_hr->isHumongous(), "it should not be humongous");
135 HeapWord* end = start + word_size;
136 assert(containing_hr->is_in(end - 1), "it should also contain end - 1");
138 MemRegion mr(start, end);
139 g1_barrier_set()->g1_mark_as_young(mr);
140 }
142 inline RefToScanQueue* G1CollectedHeap::task_queue(int i) const {
143 return _task_queues->queue(i);
144 }
146 inline bool G1CollectedHeap::isMarkedPrev(oop obj) const {
147 return _cm->prevMarkBitMap()->isMarked((HeapWord *)obj);
148 }
150 inline bool G1CollectedHeap::isMarkedNext(oop obj) const {
151 return _cm->nextMarkBitMap()->isMarked((HeapWord *)obj);
152 }
154 #ifndef PRODUCT
155 // Support for G1EvacuationFailureALot
157 inline bool
158 G1CollectedHeap::evacuation_failure_alot_for_gc_type(bool gcs_are_young,
159 bool during_initial_mark,
160 bool during_marking) {
161 bool res = false;
162 if (during_marking) {
163 res |= G1EvacuationFailureALotDuringConcMark;
164 }
165 if (during_initial_mark) {
166 res |= G1EvacuationFailureALotDuringInitialMark;
167 }
168 if (gcs_are_young) {
169 res |= G1EvacuationFailureALotDuringYoungGC;
170 } else {
171 // GCs are mixed
172 res |= G1EvacuationFailureALotDuringMixedGC;
173 }
174 return res;
175 }
177 inline void
178 G1CollectedHeap::set_evacuation_failure_alot_for_current_gc() {
179 if (G1EvacuationFailureALot) {
180 // Note we can't assert that _evacuation_failure_alot_for_current_gc
181 // is clear here. It may have been set during a previous GC but that GC
182 // did not copy enough objects (i.e. G1EvacuationFailureALotCount) to
183 // trigger an evacuation failure and clear the flags and and counts.
185 // Check if we have gone over the interval.
186 const size_t gc_num = total_collections();
187 const size_t elapsed_gcs = gc_num - _evacuation_failure_alot_gc_number;
189 _evacuation_failure_alot_for_current_gc = (elapsed_gcs >= G1EvacuationFailureALotInterval);
191 // Now check if G1EvacuationFailureALot is enabled for the current GC type.
192 const bool gcs_are_young = g1_policy()->gcs_are_young();
193 const bool during_im = g1_policy()->during_initial_mark_pause();
194 const bool during_marking = mark_in_progress();
196 _evacuation_failure_alot_for_current_gc &=
197 evacuation_failure_alot_for_gc_type(gcs_are_young,
198 during_im,
199 during_marking);
200 }
201 }
203 inline bool
204 G1CollectedHeap::evacuation_should_fail() {
205 if (!G1EvacuationFailureALot || !_evacuation_failure_alot_for_current_gc) {
206 return false;
207 }
208 // G1EvacuationFailureALot is in effect for current GC
209 // Access to _evacuation_failure_alot_count is not atomic;
210 // the value does not have to be exact.
211 if (++_evacuation_failure_alot_count < G1EvacuationFailureALotCount) {
212 return false;
213 }
214 _evacuation_failure_alot_count = 0;
215 return true;
216 }
218 inline void G1CollectedHeap::reset_evacuation_should_fail() {
219 if (G1EvacuationFailureALot) {
220 _evacuation_failure_alot_gc_number = total_collections();
221 _evacuation_failure_alot_count = 0;
222 _evacuation_failure_alot_for_current_gc = false;
223 }
224 }
225 #endif // #ifndef PRODUCT
227 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTEDHEAP_INLINE_HPP