1 /*
2 * Copyright (c) 2018, 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
26 #include "precompiled.hpp"
27 #include "logging/log.hpp"
28 #include "logging/logStream.hpp"
29 #include "memory/metaspace.hpp"
30 #include "memory/metaspace/chunkManager.hpp"
31 #include "memory/metaspace/metachunk.hpp"
32 #include "memory/metaspace/metaspaceCommon.hpp"
33 #include "memory/metaspace/virtualSpaceList.hpp"
34 #include "memory/metaspace/virtualSpaceNode.hpp"
35 #include "runtime/orderAccess.hpp"
36 #include "runtime/mutexLocker.hpp"
37 #include "runtime/safepoint.hpp"
38
39 namespace metaspace {
40
41
42 VirtualSpaceList::~VirtualSpaceList() {
43 VirtualSpaceListIterator iter(virtual_space_list());
44 while (iter.repeat()) {
45 VirtualSpaceNode* vsl = iter.get_next();
46 delete vsl;
47 }
48 }
49
50 void VirtualSpaceList::inc_reserved_words(size_t v) {
51 assert_lock_strong(MetaspaceExpand_lock);
52 _reserved_words = _reserved_words + v;
53 }
54 void VirtualSpaceList::dec_reserved_words(size_t v) {
55 assert_lock_strong(MetaspaceExpand_lock);
56 _reserved_words = _reserved_words - v;
57 }
58
59 #define assert_committed_below_limit() \
60 assert(MetaspaceUtils::committed_bytes() <= MaxMetaspaceSize, \
61 "Too much committed memory. Committed: " SIZE_FORMAT \
62 " limit (MaxMetaspaceSize): " SIZE_FORMAT, \
63 MetaspaceUtils::committed_bytes(), MaxMetaspaceSize);
64
65 void VirtualSpaceList::inc_committed_words(size_t v) {
66 assert_lock_strong(MetaspaceExpand_lock);
67 _committed_words = _committed_words + v;
68
69 assert_committed_below_limit();
70 }
71 void VirtualSpaceList::dec_committed_words(size_t v) {
72 assert_lock_strong(MetaspaceExpand_lock);
73 _committed_words = _committed_words - v;
74
75 assert_committed_below_limit();
76 }
77
78 void VirtualSpaceList::inc_virtual_space_count() {
79 assert_lock_strong(MetaspaceExpand_lock);
80 _virtual_space_count++;
81 }
82
83 void VirtualSpaceList::dec_virtual_space_count() {
84 assert_lock_strong(MetaspaceExpand_lock);
85 _virtual_space_count--;
86 }
87
88 // Walk the list of VirtualSpaceNodes and delete
89 // nodes with a 0 container_count. Remove Metachunks in
90 // the node from their respective freelists.
91 void VirtualSpaceList::purge(ChunkManager* chunk_manager) {
92 assert(SafepointSynchronize::is_at_safepoint(), "must be called at safepoint for contains to work");
93 assert_lock_strong(MetaspaceExpand_lock);
94 // Don't use a VirtualSpaceListIterator because this
95 // list is being changed and a straightforward use of an iterator is not safe.
96 VirtualSpaceNode* purged_vsl = NULL;
97 VirtualSpaceNode* prev_vsl = virtual_space_list();
98 VirtualSpaceNode* next_vsl = prev_vsl;
99 while (next_vsl != NULL) {
100 VirtualSpaceNode* vsl = next_vsl;
101 DEBUG_ONLY(vsl->verify_container_count();)
102 next_vsl = vsl->next();
103 // Don't free the current virtual space since it will likely
104 // be needed soon.
105 if (vsl->container_count() == 0 && vsl != current_virtual_space()) {
106 log_trace(gc, metaspace, freelist)("Purging VirtualSpaceNode " PTR_FORMAT " (capacity: " SIZE_FORMAT
107 ", used: " SIZE_FORMAT ").", p2i(vsl), vsl->capacity_words_in_vs(), vsl->used_words_in_vs());
108 DEBUG_ONLY(Atomic::inc(&g_internal_statistics.num_vsnodes_purged));
109 // Unlink it from the list
110 if (prev_vsl == vsl) {
111 // This is the case of the current node being the first node.
112 assert(vsl == virtual_space_list(), "Expected to be the first node");
113 set_virtual_space_list(vsl->next());
114 } else {
115 prev_vsl->set_next(vsl->next());
116 }
117
118 vsl->purge(chunk_manager);
119 dec_reserved_words(vsl->reserved_words());
120 dec_committed_words(vsl->committed_words());
121 dec_virtual_space_count();
122 purged_vsl = vsl;
123 delete vsl;
124 } else {
125 prev_vsl = vsl;
126 }
127 }
128 #ifdef ASSERT
129 if (purged_vsl != NULL) {
130 // List should be stable enough to use an iterator here.
131 VirtualSpaceListIterator iter(virtual_space_list());
132 while (iter.repeat()) {
133 VirtualSpaceNode* vsl = iter.get_next();
134 assert(vsl != purged_vsl, "Purge of vsl failed");
135 }
136 }
137 #endif
138 }
139
140
141 // This function looks at the mmap regions in the metaspace without locking.
142 // The chunks are added with store ordering and not deleted except for at
143 // unloading time during a safepoint.
144 bool VirtualSpaceList::contains(const void* ptr) {
145 // List should be stable enough to use an iterator here because removing virtual
146 // space nodes is only allowed at a safepoint.
147 VirtualSpaceListIterator iter(virtual_space_list());
148 while (iter.repeat()) {
149 VirtualSpaceNode* vsn = iter.get_next();
150 if (vsn->contains(ptr)) {
151 return true;
152 }
153 }
154 return false;
155 }
156
157 void VirtualSpaceList::retire_current_virtual_space() {
158 assert_lock_strong(MetaspaceExpand_lock);
159
160 VirtualSpaceNode* vsn = current_virtual_space();
161
162 ChunkManager* cm = is_class() ? Metaspace::chunk_manager_class() :
163 Metaspace::chunk_manager_metadata();
164
165 vsn->retire(cm);
166 }
167
168 VirtualSpaceList::VirtualSpaceList(size_t word_size) :
169 _virtual_space_list(NULL),
170 _current_virtual_space(NULL),
171 _is_class(false),
172 _reserved_words(0),
173 _committed_words(0),
174 _virtual_space_count(0) {
175 MutexLockerEx cl(MetaspaceExpand_lock,
176 Mutex::_no_safepoint_check_flag);
177 create_new_virtual_space(word_size);
178 }
179
180 VirtualSpaceList::VirtualSpaceList(ReservedSpace rs) :
181 _virtual_space_list(NULL),
182 _current_virtual_space(NULL),
183 _is_class(true),
184 _reserved_words(0),
185 _committed_words(0),
186 _virtual_space_count(0) {
187 MutexLockerEx cl(MetaspaceExpand_lock,
188 Mutex::_no_safepoint_check_flag);
189 VirtualSpaceNode* class_entry = new VirtualSpaceNode(is_class(), rs);
190 bool succeeded = class_entry->initialize();
191 if (succeeded) {
192 link_vs(class_entry);
193 }
194 }
195
196 size_t VirtualSpaceList::free_bytes() {
197 return current_virtual_space()->free_words_in_vs() * BytesPerWord;
198 }
199
200 // Allocate another meta virtual space and add it to the list.
201 bool VirtualSpaceList::create_new_virtual_space(size_t vs_word_size) {
202 assert_lock_strong(MetaspaceExpand_lock);
203
204 if (is_class()) {
205 assert(false, "We currently don't support more than one VirtualSpace for"
206 " the compressed class space. The initialization of the"
207 " CCS uses another code path and should not hit this path.");
208 return false;
209 }
210
211 if (vs_word_size == 0) {
212 assert(false, "vs_word_size should always be at least _reserve_alignment large.");
213 return false;
214 }
215
216 // Reserve the space
217 size_t vs_byte_size = vs_word_size * BytesPerWord;
218 assert_is_aligned(vs_byte_size, Metaspace::reserve_alignment());
219
220 // Allocate the meta virtual space and initialize it.
221 VirtualSpaceNode* new_entry = new VirtualSpaceNode(is_class(), vs_byte_size);
222 if (!new_entry->initialize()) {
223 delete new_entry;
224 return false;
225 } else {
226 assert(new_entry->reserved_words() == vs_word_size,
227 "Reserved memory size differs from requested memory size");
228 // ensure lock-free iteration sees fully initialized node
229 OrderAccess::storestore();
230 link_vs(new_entry);
231 DEBUG_ONLY(Atomic::inc(&g_internal_statistics.num_vsnodes_created));
232 return true;
233 }
234 }
235
236 void VirtualSpaceList::link_vs(VirtualSpaceNode* new_entry) {
237 if (virtual_space_list() == NULL) {
238 set_virtual_space_list(new_entry);
239 } else {
240 current_virtual_space()->set_next(new_entry);
241 }
242 set_current_virtual_space(new_entry);
243 inc_reserved_words(new_entry->reserved_words());
244 inc_committed_words(new_entry->committed_words());
245 inc_virtual_space_count();
246 #ifdef ASSERT
247 new_entry->mangle();
248 #endif
249 LogTarget(Trace, gc, metaspace) lt;
250 if (lt.is_enabled()) {
251 LogStream ls(lt);
252 VirtualSpaceNode* vsl = current_virtual_space();
253 ResourceMark rm;
254 vsl->print_on(&ls);
255 }
256 }
257
258 bool VirtualSpaceList::expand_node_by(VirtualSpaceNode* node,
259 size_t min_words,
260 size_t preferred_words) {
261 size_t before = node->committed_words();
262
263 bool result = node->expand_by(min_words, preferred_words);
264
265 size_t after = node->committed_words();
266
267 // after and before can be the same if the memory was pre-committed.
268 assert(after >= before, "Inconsistency");
269 inc_committed_words(after - before);
270
271 return result;
272 }
273
274 bool VirtualSpaceList::expand_by(size_t min_words, size_t preferred_words) {
275 assert_is_aligned(min_words, Metaspace::commit_alignment_words());
276 assert_is_aligned(preferred_words, Metaspace::commit_alignment_words());
277 assert(min_words <= preferred_words, "Invalid arguments");
278
279 const char* const class_or_not = (is_class() ? "class" : "non-class");
280
281 if (!MetaspaceGC::can_expand(min_words, this->is_class())) {
282 log_trace(gc, metaspace, freelist)("Cannot expand %s virtual space list.",
283 class_or_not);
284 return false;
285 }
286
287 size_t allowed_expansion_words = MetaspaceGC::allowed_expansion();
288 if (allowed_expansion_words < min_words) {
289 log_trace(gc, metaspace, freelist)("Cannot expand %s virtual space list (must try gc first).",
290 class_or_not);
291 return false;
292 }
293
294 size_t max_expansion_words = MIN2(preferred_words, allowed_expansion_words);
295
296 // Commit more memory from the the current virtual space.
297 bool vs_expanded = expand_node_by(current_virtual_space(),
298 min_words,
299 max_expansion_words);
300 if (vs_expanded) {
301 log_trace(gc, metaspace, freelist)("Expanded %s virtual space list.",
302 class_or_not);
303 return true;
304 }
305 log_trace(gc, metaspace, freelist)("%s virtual space list: retire current node.",
306 class_or_not);
307 retire_current_virtual_space();
308
309 // Get another virtual space.
310 size_t grow_vs_words = MAX2((size_t)VirtualSpaceSize, preferred_words);
311 grow_vs_words = align_up(grow_vs_words, Metaspace::reserve_alignment_words());
312
313 if (create_new_virtual_space(grow_vs_words)) {
314 if (current_virtual_space()->is_pre_committed()) {
315 // The memory was pre-committed, so we are done here.
316 assert(min_words <= current_virtual_space()->committed_words(),
317 "The new VirtualSpace was pre-committed, so it"
318 "should be large enough to fit the alloc request.");
319 return true;
320 }
321
322 return expand_node_by(current_virtual_space(),
323 min_words,
324 max_expansion_words);
325 }
326
327 return false;
328 }
329
330 // Given a chunk, calculate the largest possible padding space which
331 // could be required when allocating it.
332 static size_t largest_possible_padding_size_for_chunk(size_t chunk_word_size, bool is_class) {
333 const ChunkIndex chunk_type = get_chunk_type_by_size(chunk_word_size, is_class);
334 if (chunk_type != HumongousIndex) {
335 // Normal, non-humongous chunks are allocated at chunk size
336 // boundaries, so the largest padding space required would be that
337 // minus the smallest chunk size.
338 const size_t smallest_chunk_size = is_class ? ClassSpecializedChunk : SpecializedChunk;
339 return chunk_word_size - smallest_chunk_size;
340 } else {
341 // Humongous chunks are allocated at smallest-chunksize
342 // boundaries, so there is no padding required.
343 return 0;
344 }
345 }
346
347
348 Metachunk* VirtualSpaceList::get_new_chunk(size_t chunk_word_size, size_t suggested_commit_granularity) {
349
350 // Allocate a chunk out of the current virtual space.
351 Metachunk* next = current_virtual_space()->get_chunk_vs(chunk_word_size);
352
353 if (next != NULL) {
354 return next;
355 }
356
357 // The expand amount is currently only determined by the requested sizes
358 // and not how much committed memory is left in the current virtual space.
359
360 // We must have enough space for the requested size and any
361 // additional reqired padding chunks.
362 const size_t size_for_padding = largest_possible_padding_size_for_chunk(chunk_word_size, this->is_class());
363
364 size_t min_word_size = align_up(chunk_word_size + size_for_padding, Metaspace::commit_alignment_words());
365 size_t preferred_word_size = align_up(suggested_commit_granularity, Metaspace::commit_alignment_words());
366 if (min_word_size >= preferred_word_size) {
367 // Can happen when humongous chunks are allocated.
368 preferred_word_size = min_word_size;
369 }
370
371 bool expanded = expand_by(min_word_size, preferred_word_size);
372 if (expanded) {
373 next = current_virtual_space()->get_chunk_vs(chunk_word_size);
374 assert(next != NULL, "The allocation was expected to succeed after the expansion");
375 }
376
377 return next;
378 }
379
380 void VirtualSpaceList::print_on(outputStream* st, size_t scale) const {
381 st->print_cr(SIZE_FORMAT " nodes, current node: " PTR_FORMAT,
382 _virtual_space_count, p2i(_current_virtual_space));
383 VirtualSpaceListIterator iter(virtual_space_list());
384 while (iter.repeat()) {
385 st->cr();
386 VirtualSpaceNode* node = iter.get_next();
387 node->print_on(st, scale);
388 }
389 }
390
391 void VirtualSpaceList::print_map(outputStream* st) const {
392 VirtualSpaceNode* list = virtual_space_list();
393 VirtualSpaceListIterator iter(list);
394 unsigned i = 0;
395 while (iter.repeat()) {
396 st->print_cr("Node %u:", i);
397 VirtualSpaceNode* node = iter.get_next();
398 node->print_map(st, this->is_class());
399 i ++;
400 }
401 }
402
403 } // namespace metaspace
404