1 /*
2 * Copyright (c) 2014, 2020, 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.
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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
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23 */
24
25 #ifndef SHARE_GC_G1_G1PARSCANTHREADSTATE_INLINE_HPP
26 #define SHARE_GC_G1_G1PARSCANTHREADSTATE_INLINE_HPP
27
28 #include "gc/g1/g1CollectedHeap.inline.hpp"
29 #include "gc/g1/g1OopStarChunkedList.inline.hpp"
30 #include "gc/g1/g1ParScanThreadState.hpp"
31 #include "gc/g1/g1RemSet.hpp"
32 #include "oops/access.inline.hpp"
33 #include "oops/oop.inline.hpp"
34
35 template <class T> void G1ParScanThreadState::do_oop_evac(T* p) {
36 // Reference should not be NULL here as such are never pushed to the task queue.
37 oop obj = RawAccess<IS_NOT_NULL>::oop_load(p);
38
39 // Although we never intentionally push references outside of the collection
40 // set, due to (benign) races in the claim mechanism during RSet scanning more
41 // than one thread might claim the same card. So the same card may be
42 // processed multiple times, and so we might get references into old gen here.
43 // So we need to redo this check.
44 const G1HeapRegionAttr region_attr = _g1h->region_attr(obj);
45 // References pushed onto the work stack should never point to a humongous region
46 // as they are not added to the collection set due to above precondition.
47 assert(!region_attr.is_humongous(),
48 "Obj " PTR_FORMAT " should not refer to humongous region %u from " PTR_FORMAT,
49 p2i(obj), _g1h->addr_to_region(cast_from_oop<HeapWord*>(obj)), p2i(p));
50
51 if (!region_attr.is_in_cset()) {
52 // In this case somebody else already did all the work.
53 return;
54 }
55
56 markWord m = obj->mark_raw();
57 if (m.is_marked()) {
58 obj = (oop) m.decode_pointer();
59 } else {
60 obj = copy_to_survivor_space(region_attr, obj, m);
61 }
62 RawAccess<IS_NOT_NULL>::oop_store(p, obj);
63
64 assert(obj != NULL, "Must be");
65 if (HeapRegion::is_in_same_region(p, obj)) {
66 return;
67 }
68 HeapRegion* from = _g1h->heap_region_containing(p);
69 if (!from->is_young()) {
70 enqueue_card_if_tracked(_g1h->region_attr(obj), p, obj);
71 }
72 }
73
74 inline void G1ParScanThreadState::push_on_queue(ScannerTask task) {
75 verify_task(task);
76 _task_queue->push(task);
77 }
78
79 inline void G1ParScanThreadState::do_partial_array(PartialArrayScanTask task) {
80 oop from_obj = task.to_source_array();
81
82 assert(_g1h->is_in_reserved(from_obj), "must be in heap.");
83 assert(from_obj->is_objArray(), "must be obj array");
84 objArrayOop from_obj_array = objArrayOop(from_obj);
85 // The from-space object contains the real length.
86 int length = from_obj_array->length();
87
88 assert(from_obj->is_forwarded(), "must be forwarded");
89 oop to_obj = from_obj->forwardee();
90 assert(from_obj != to_obj, "should not be chunking self-forwarded objects");
91 objArrayOop to_obj_array = objArrayOop(to_obj);
92 // We keep track of the next start index in the length field of the
93 // to-space object.
94 int next_index = to_obj_array->length();
95 assert(0 <= next_index && next_index < length,
96 "invariant, next index: %d, length: %d", next_index, length);
97
98 int start = next_index;
99 int end = length;
100 int remainder = end - start;
101 // We'll try not to push a range that's smaller than ParGCArrayScanChunk.
102 if (remainder > 2 * ParGCArrayScanChunk) {
103 end = start + ParGCArrayScanChunk;
104 to_obj_array->set_length(end);
105 // Push the remainder before we process the range in case another
106 // worker has run out of things to do and can steal it.
107 push_on_queue(ScannerTask(PartialArrayScanTask(from_obj)));
108 } else {
109 assert(length == end, "sanity");
110 // We'll process the final range for this object. Restore the length
111 // so that the heap remains parsable in case of evacuation failure.
112 to_obj_array->set_length(end);
113 }
114
115 HeapRegion* hr = _g1h->heap_region_containing(to_obj);
116 G1ScanInYoungSetter x(&_scanner, hr->is_young());
117 // Process indexes [start,end). It will also process the header
118 // along with the first chunk (i.e., the chunk with start == 0).
119 // Note that at this point the length field of to_obj_array is not
120 // correct given that we are using it to keep track of the next
121 // start index. oop_iterate_range() (thankfully!) ignores the length
122 // field and only relies on the start / end parameters. It does
123 // however return the size of the object which will be incorrect. So
124 // we have to ignore it even if we wanted to use it.
125 to_obj_array->oop_iterate_range(&_scanner, start, end);
126 }
127
128 inline void G1ParScanThreadState::dispatch_task(ScannerTask task) {
129 verify_task(task);
130 if (task.is_narrow_oop_ptr()) {
131 do_oop_evac(task.to_narrow_oop_ptr());
132 } else if (task.is_oop_ptr()) {
133 do_oop_evac(task.to_oop_ptr());
134 } else {
135 do_partial_array(task.to_partial_array_task());
136 }
137 }
138
139 void G1ParScanThreadState::steal_and_trim_queue(ScannerTasksQueueSet *task_queues) {
140 ScannerTask stolen_task;
141 while (task_queues->steal(_worker_id, stolen_task)) {
142 dispatch_task(stolen_task);
143
144 // We've just processed a task and we might have made
145 // available new entries on the queues. So we have to make sure
146 // we drain the queues as necessary.
147 trim_queue();
148 }
149 }
150
151 inline bool G1ParScanThreadState::needs_partial_trimming() const {
152 return !_task_queue->overflow_empty() ||
153 (_task_queue->size() > _stack_trim_upper_threshold);
154 }
155
156 inline bool G1ParScanThreadState::is_partially_trimmed() const {
157 return _task_queue->overflow_empty() &&
158 (_task_queue->size() <= _stack_trim_lower_threshold);
159 }
160
161 inline void G1ParScanThreadState::trim_queue_to_threshold(uint threshold) {
162 ScannerTask task;
163 // Drain the overflow stack first, so other threads can potentially steal.
164 while (_task_queue->pop_overflow(task)) {
165 if (!_task_queue->try_push_to_taskqueue(task)) {
166 dispatch_task(task);
167 }
168 }
169
170 while (_task_queue->pop_local(task, threshold)) {
171 dispatch_task(task);
172 }
173 }
174
175 inline void G1ParScanThreadState::trim_queue_partially() {
176 if (!needs_partial_trimming()) {
177 return;
178 }
179
180 const Ticks start = Ticks::now();
181 do {
182 trim_queue_to_threshold(_stack_trim_lower_threshold);
183 } while (!is_partially_trimmed());
184 _trim_ticks += Ticks::now() - start;
185 }
186
187 inline Tickspan G1ParScanThreadState::trim_ticks() const {
188 return _trim_ticks;
189 }
190
191 inline void G1ParScanThreadState::reset_trim_ticks() {
192 _trim_ticks = Tickspan();
193 }
194
195 template <typename T>
196 inline void G1ParScanThreadState::remember_root_into_optional_region(T* p) {
197 oop o = RawAccess<IS_NOT_NULL>::oop_load(p);
198 uint index = _g1h->heap_region_containing(o)->index_in_opt_cset();
199 assert(index < _num_optional_regions,
200 "Trying to access optional region idx %u beyond " SIZE_FORMAT, index, _num_optional_regions);
201 _oops_into_optional_regions[index].push_root(p);
202 }
203
204 template <typename T>
205 inline void G1ParScanThreadState::remember_reference_into_optional_region(T* p) {
206 oop o = RawAccess<IS_NOT_NULL>::oop_load(p);
207 uint index = _g1h->heap_region_containing(o)->index_in_opt_cset();
208 assert(index < _num_optional_regions,
209 "Trying to access optional region idx %u beyond " SIZE_FORMAT, index, _num_optional_regions);
210 _oops_into_optional_regions[index].push_oop(p);
211 verify_task(p);
212 }
213
214 G1OopStarChunkedList* G1ParScanThreadState::oops_into_optional_region(const HeapRegion* hr) {
215 assert(hr->index_in_opt_cset() < _num_optional_regions,
216 "Trying to access optional region idx %u beyond " SIZE_FORMAT " " HR_FORMAT,
217 hr->index_in_opt_cset(), _num_optional_regions, HR_FORMAT_PARAMS(hr));
218 return &_oops_into_optional_regions[hr->index_in_opt_cset()];
219 }
220
221 void G1ParScanThreadState::initialize_numa_stats() {
222 if (_numa->is_enabled()) {
223 LogTarget(Info, gc, heap, numa) lt;
224
225 if (lt.is_enabled()) {
226 uint num_nodes = _numa->num_active_nodes();
227 // Record only if there are multiple active nodes.
228 _obj_alloc_stat = NEW_C_HEAP_ARRAY(size_t, num_nodes, mtGC);
229 memset(_obj_alloc_stat, 0, sizeof(size_t) * num_nodes);
230 }
231 }
232 }
233
234 void G1ParScanThreadState::flush_numa_stats() {
235 if (_obj_alloc_stat != NULL) {
236 uint node_index = _numa->index_of_current_thread();
237 _numa->copy_statistics(G1NUMAStats::LocalObjProcessAtCopyToSurv, node_index, _obj_alloc_stat);
238 }
239 }
240
241 void G1ParScanThreadState::update_numa_stats(uint node_index) {
242 if (_obj_alloc_stat != NULL) {
243 _obj_alloc_stat[node_index]++;
244 }
245 }
246
247 #endif // SHARE_GC_G1_G1PARSCANTHREADSTATE_INLINE_HPP