1 /*
2 * Copyright (c) 2015, 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 #include "precompiled.hpp"
26 #include "gc/g1/g1CollectedHeap.hpp"
27 #include "gc/g1/g1CollectorPolicy.hpp"
28 #include "gc/g1/heapRegion.hpp"
29 #include "gc/g1/heapRegion.inline.hpp"
30 #include "gc/g1/heapRegionRemSet.hpp"
31 #include "gc/g1/youngList.hpp"
32 #include "logging/log.hpp"
33 #include "utilities/ostream.hpp"
34
35 YoungList::YoungList(G1CollectedHeap* g1h) :
36 _g1h(g1h), _head(NULL), _length(0), _last_sampled_rs_lengths(0),
37 _survivor_head(NULL), _survivor_tail(NULL), _survivor_length(0) {
38 guarantee(check_list_empty(false), "just making sure...");
39 }
40
41 void YoungList::push_region(HeapRegion *hr) {
42 assert(!hr->is_young(), "should not already be young");
43 assert(hr->get_next_young_region() == NULL, "cause it should!");
44
45 hr->set_next_young_region(_head);
46 _head = hr;
47
48 _g1h->g1_policy()->set_region_eden(hr, (int) _length);
49 ++_length;
50 }
51
52 void YoungList::add_survivor_region(HeapRegion* hr) {
53 assert(hr->is_survivor(), "should be flagged as survivor region");
54 assert(hr->get_next_young_region() == NULL, "cause it should!");
55
56 hr->set_next_young_region(_survivor_head);
57 if (_survivor_head == NULL) {
58 _survivor_tail = hr;
59 }
60 _survivor_head = hr;
61 ++_survivor_length;
62 }
63
64 void YoungList::empty_list(HeapRegion* list) {
65 while (list != NULL) {
66 HeapRegion* next = list->get_next_young_region();
67 list->set_next_young_region(NULL);
68 list->uninstall_surv_rate_group();
69 // This is called before a Full GC and all the non-empty /
70 // non-humongous regions at the end of the Full GC will end up as
71 // old anyway.
72 list->set_old();
73 list = next;
74 }
75 }
76
77 void YoungList::empty_list() {
78 assert(check_list_well_formed(), "young list should be well formed");
79
80 empty_list(_head);
81 _head = NULL;
82 _length = 0;
83
84 empty_list(_survivor_head);
85 _survivor_head = NULL;
86 _survivor_tail = NULL;
87 _survivor_length = 0;
88
89 _last_sampled_rs_lengths = 0;
90
91 assert(check_list_empty(false), "just making sure...");
92 }
93
94 bool YoungList::check_list_well_formed() {
95 bool ret = true;
96
97 uint length = 0;
98 HeapRegion* curr = _head;
99 HeapRegion* last = NULL;
100 while (curr != NULL) {
101 if (!curr->is_young()) {
102 log_info(gc, verify)("### YOUNG REGION " PTR_FORMAT "-" PTR_FORMAT " "
103 "incorrectly tagged (y: %d, surv: %d)",
104 p2i(curr->bottom()), p2i(curr->end()),
105 curr->is_young(), curr->is_survivor());
106 ret = false;
107 }
108 ++length;
109 last = curr;
110 curr = curr->get_next_young_region();
111 }
112 ret = ret && (length == _length);
113
114 if (!ret) {
115 log_info(gc, verify)("### YOUNG LIST seems not well formed!");
116 log_info(gc, verify)("### list has %u entries, _length is %u", length, _length);
117 }
118
119 return ret;
120 }
121
122 bool YoungList::check_list_empty(bool check_sample) {
123 bool ret = true;
124
125 if (_length != 0) {
126 log_info(gc, verify)("### YOUNG LIST should have 0 length, not %u", _length);
127 ret = false;
128 }
129 if (check_sample && _last_sampled_rs_lengths != 0) {
130 log_info(gc, verify)("### YOUNG LIST has non-zero last sampled RS lengths");
131 ret = false;
132 }
133 if (_head != NULL) {
134 log_info(gc, verify)("### YOUNG LIST does not have a NULL head");
135 ret = false;
136 }
137 if (!ret) {
138 log_info(gc, verify)("### YOUNG LIST does not seem empty");
139 }
140
141 return ret;
142 }
143
144 void
145 YoungList::rs_length_sampling_init() {
146 _sampled_rs_lengths = 0;
147 _curr = _head;
148 }
149
150 bool
151 YoungList::rs_length_sampling_more() {
152 return _curr != NULL;
153 }
154
155 void
156 YoungList::rs_length_sampling_next() {
157 assert( _curr != NULL, "invariant" );
158 size_t rs_length = _curr->rem_set()->occupied();
159
160 _sampled_rs_lengths += rs_length;
161
162 // The current region may not yet have been added to the
163 // incremental collection set (it gets added when it is
164 // retired as the current allocation region).
165 if (_curr->in_collection_set()) {
166 // Update the collection set policy information for this region
167 _g1h->g1_policy()->update_incremental_cset_info(_curr, rs_length);
168 }
169
170 _curr = _curr->get_next_young_region();
171 if (_curr == NULL) {
172 _last_sampled_rs_lengths = _sampled_rs_lengths;
173 }
174 }
175
176 void
177 YoungList::reset_auxilary_lists() {
178 guarantee( is_empty(), "young list should be empty" );
179 assert(check_list_well_formed(), "young list should be well formed");
180
181 // Add survivor regions to SurvRateGroup.
182 _g1h->g1_policy()->note_start_adding_survivor_regions();
183 _g1h->g1_policy()->finished_recalculating_age_indexes(true /* is_survivors */);
184
185 int young_index_in_cset = 0;
186 for (HeapRegion* curr = _survivor_head;
187 curr != NULL;
188 curr = curr->get_next_young_region()) {
189 _g1h->g1_policy()->set_region_survivor(curr, young_index_in_cset);
190
191 // The region is a non-empty survivor so let's add it to
192 // the incremental collection set for the next evacuation
193 // pause.
194 _g1h->g1_policy()->add_region_to_incremental_cset_rhs(curr);
195 young_index_in_cset += 1;
196 }
197 assert((uint) young_index_in_cset == _survivor_length, "post-condition");
198 _g1h->g1_policy()->note_stop_adding_survivor_regions();
199
200 _head = _survivor_head;
201 _length = _survivor_length;
202 if (_survivor_head != NULL) {
203 assert(_survivor_tail != NULL, "cause it shouldn't be");
204 assert(_survivor_length > 0, "invariant");
205 _survivor_tail->set_next_young_region(NULL);
206 }
207
208 // Don't clear the survivor list handles until the start of
209 // the next evacuation pause - we need it in order to re-tag
210 // the survivor regions from this evacuation pause as 'young'
211 // at the start of the next.
212
213 _g1h->g1_policy()->finished_recalculating_age_indexes(false /* is_survivors */);
214
215 assert(check_list_well_formed(), "young list should be well formed");
216 }
217
218 void YoungList::print() {
219 HeapRegion* lists[] = {_head, _survivor_head};
220 const char* names[] = {"YOUNG", "SURVIVOR"};
221
222 for (uint list = 0; list < ARRAY_SIZE(lists); ++list) {
223 tty->print_cr("%s LIST CONTENTS", names[list]);
224 HeapRegion *curr = lists[list];
225 if (curr == NULL) {
226 tty->print_cr(" empty");
227 }
228 while (curr != NULL) {
229 tty->print_cr(" " HR_FORMAT ", P: " PTR_FORMAT ", N: " PTR_FORMAT ", age: %4d",
230 HR_FORMAT_PARAMS(curr),
231 p2i(curr->prev_top_at_mark_start()),
232 p2i(curr->next_top_at_mark_start()),
233 curr->age_in_surv_rate_group_cond());
234 curr = curr->get_next_young_region();
235 }
236 }
237
238 tty->cr();
239 }