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 "utilities/ostream.hpp"
33
34 YoungList::YoungList(G1CollectedHeap* g1h) :
35 _g1h(g1h), _head(NULL), _length(0), _last_sampled_rs_lengths(0),
36 _survivor_head(NULL), _survivor_tail(NULL), _survivor_length(0) {
37 guarantee(check_list_empty(false), "just making sure...");
38 }
39
40 void YoungList::push_region(HeapRegion *hr) {
41 assert(!hr->is_young(), "should not already be young");
42 assert(hr->get_next_young_region() == NULL, "cause it should!");
43
44 hr->set_next_young_region(_head);
45 _head = hr;
46
47 _g1h->g1_policy()->set_region_eden(hr, (int) _length);
48 ++_length;
49 }
50
51 void YoungList::add_survivor_region(HeapRegion* hr) {
52 assert(hr->is_survivor(), "should be flagged as survivor region");
53 assert(hr->get_next_young_region() == NULL, "cause it should!");
54
55 hr->set_next_young_region(_survivor_head);
56 if (_survivor_head == NULL) {
57 _survivor_tail = hr;
58 }
59 _survivor_head = hr;
60 ++_survivor_length;
61 }
62
63 void YoungList::empty_list(HeapRegion* list) {
64 while (list != NULL) {
65 HeapRegion* next = list->get_next_young_region();
66 list->set_next_young_region(NULL);
67 list->uninstall_surv_rate_group();
68 // This is called before a Full GC and all the non-empty /
69 // non-humongous regions at the end of the Full GC will end up as
70 // old anyway.
71 list->set_old();
72 list = next;
73 }
74 }
75
76 void YoungList::empty_list() {
77 assert(check_list_well_formed(), "young list should be well formed");
78
79 empty_list(_head);
80 _head = NULL;
81 _length = 0;
82
83 empty_list(_survivor_head);
84 _survivor_head = NULL;
85 _survivor_tail = NULL;
86 _survivor_length = 0;
87
88 _last_sampled_rs_lengths = 0;
89
90 assert(check_list_empty(false), "just making sure...");
91 }
92
93 bool YoungList::check_list_well_formed() {
94 bool ret = true;
95
96 uint length = 0;
97 HeapRegion* curr = _head;
98 HeapRegion* last = NULL;
99 while (curr != NULL) {
100 if (!curr->is_young()) {
101 gclog_or_tty->print_cr("### YOUNG REGION " PTR_FORMAT "-" PTR_FORMAT " "
102 "incorrectly tagged (y: %d, surv: %d)",
103 p2i(curr->bottom()), p2i(curr->end()),
104 curr->is_young(), curr->is_survivor());
105 ret = false;
106 }
107 ++length;
108 last = curr;
109 curr = curr->get_next_young_region();
110 }
111 ret = ret && (length == _length);
112
113 if (!ret) {
114 gclog_or_tty->print_cr("### YOUNG LIST seems not well formed!");
115 gclog_or_tty->print_cr("### list has %u entries, _length is %u",
116 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 gclog_or_tty->print_cr("### YOUNG LIST should have 0 length, not %u",
127 _length);
128 ret = false;
129 }
130 if (check_sample && _last_sampled_rs_lengths != 0) {
131 gclog_or_tty->print_cr("### YOUNG LIST has non-zero last sampled RS lengths");
132 ret = false;
133 }
134 if (_head != NULL) {
135 gclog_or_tty->print_cr("### YOUNG LIST does not have a NULL head");
136 ret = false;
137 }
138 if (!ret) {
139 gclog_or_tty->print_cr("### YOUNG LIST does not seem empty");
140 }
141
142 return ret;
143 }
144
145 void
146 YoungList::rs_length_sampling_init() {
147 _sampled_rs_lengths = 0;
148 _curr = _head;
149 }
150
151 bool
152 YoungList::rs_length_sampling_more() {
153 return _curr != NULL;
154 }
155
156 void
157 YoungList::rs_length_sampling_next() {
158 assert( _curr != NULL, "invariant" );
159 size_t rs_length = _curr->rem_set()->occupied();
160
161 _sampled_rs_lengths += rs_length;
162
163 // The current region may not yet have been added to the
164 // incremental collection set (it gets added when it is
165 // retired as the current allocation region).
166 if (_curr->in_collection_set()) {
167 // Update the collection set policy information for this region
168 _g1h->g1_policy()->update_incremental_cset_info(_curr, rs_length);
169 }
170
171 _curr = _curr->get_next_young_region();
172 if (_curr == NULL) {
173 _last_sampled_rs_lengths = _sampled_rs_lengths;
174 // gclog_or_tty->print_cr("last sampled RS lengths = %d", _last_sampled_rs_lengths);
175 }
176 }
177
178 void
179 YoungList::reset_auxilary_lists() {
180 guarantee( is_empty(), "young list should be empty" );
181 assert(check_list_well_formed(), "young list should be well formed");
182
183 // Add survivor regions to SurvRateGroup.
184 _g1h->g1_policy()->note_start_adding_survivor_regions();
185 _g1h->g1_policy()->finished_recalculating_age_indexes(true /* is_survivors */);
186
187 int young_index_in_cset = 0;
188 for (HeapRegion* curr = _survivor_head;
189 curr != NULL;
190 curr = curr->get_next_young_region()) {
191 _g1h->g1_policy()->set_region_survivor(curr, young_index_in_cset);
192
193 // The region is a non-empty survivor so let's add it to
194 // the incremental collection set for the next evacuation
195 // pause.
196 _g1h->g1_policy()->add_region_to_incremental_cset_rhs(curr);
197 young_index_in_cset += 1;
198 }
199 assert((uint) young_index_in_cset == _survivor_length, "post-condition");
200 _g1h->g1_policy()->note_stop_adding_survivor_regions();
201
202 _head = _survivor_head;
203 _length = _survivor_length;
204 if (_survivor_head != NULL) {
205 assert(_survivor_tail != NULL, "cause it shouldn't be");
206 assert(_survivor_length > 0, "invariant");
207 _survivor_tail->set_next_young_region(NULL);
208 }
209
210 // Don't clear the survivor list handles until the start of
211 // the next evacuation pause - we need it in order to re-tag
212 // the survivor regions from this evacuation pause as 'young'
213 // at the start of the next.
214
215 _g1h->g1_policy()->finished_recalculating_age_indexes(false /* is_survivors */);
216
217 assert(check_list_well_formed(), "young list should be well formed");
218 }
219
220 void YoungList::print() {
221 HeapRegion* lists[] = {_head, _survivor_head};
222 const char* names[] = {"YOUNG", "SURVIVOR"};
223
224 for (uint list = 0; list < ARRAY_SIZE(lists); ++list) {
225 gclog_or_tty->print_cr("%s LIST CONTENTS", names[list]);
226 HeapRegion *curr = lists[list];
227 if (curr == NULL) {
228 gclog_or_tty->print_cr(" empty");
229 }
230 while (curr != NULL) {
231 gclog_or_tty->print_cr(" " HR_FORMAT ", P: " PTR_FORMAT ", N: " PTR_FORMAT ", age: %4d",
232 HR_FORMAT_PARAMS(curr),
233 p2i(curr->prev_top_at_mark_start()),
234 p2i(curr->next_top_at_mark_start()),
235 curr->age_in_surv_rate_group_cond());
236 curr = curr->get_next_young_region();
237 }
238 }
239
240 gclog_or_tty->cr();
241 }