1/*
2 * Copyright (c) 2018, 2019, 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
39namespace metaspace {
40
41
42VirtualSpaceList::~VirtualSpaceList() {
43 VirtualSpaceListIterator iter(virtual_space_list());
44 while (iter.repeat()) {
45 VirtualSpaceNode* vsl = iter.get_next();
46 delete vsl;
47 }
48}
49
50void VirtualSpaceList::inc_reserved_words(size_t v) {
51 assert_lock_strong(MetaspaceExpand_lock);
52 _reserved_words = _reserved_words + v;
53}
54void 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
65void 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}
71void 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
78void VirtualSpaceList::inc_virtual_space_count() {
79 assert_lock_strong(MetaspaceExpand_lock);
80 _virtual_space_count++;
81}
82
83void 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.
91void VirtualSpaceList::purge(ChunkManager* chunk_manager) {
92 assert_lock_strong(MetaspaceExpand_lock);
93 // Don't use a VirtualSpaceListIterator because this
94 // list is being changed and a straightforward use of an iterator is not safe.
95 VirtualSpaceNode* prev_vsl = virtual_space_list();
96 VirtualSpaceNode* next_vsl = prev_vsl;
97 int num_purged_nodes = 0;
98 while (next_vsl != NULL) {
99 VirtualSpaceNode* vsl = next_vsl;
100 DEBUG_ONLY(vsl->verify(false);)
101 next_vsl = vsl->next();
102 // Don't free the current virtual space since it will likely
103 // be needed soon.
104 if (vsl->container_count() == 0 && vsl != current_virtual_space()) {
105 log_trace(gc, metaspace, freelist)("Purging VirtualSpaceNode " PTR_FORMAT " (capacity: " SIZE_FORMAT
106 ", used: " SIZE_FORMAT ").", p2i(vsl), vsl->capacity_words_in_vs(), vsl->used_words_in_vs());
107 DEBUG_ONLY(Atomic::inc(&g_internal_statistics.num_vsnodes_purged));
108 // Unlink it from the list
109 if (prev_vsl == vsl) {
110 // This is the case of the current node being the first node.
111 assert(vsl == virtual_space_list(), "Expected to be the first node");
112 set_virtual_space_list(vsl->next());
113 } else {
114 prev_vsl->set_next(vsl->next());
115 }
116
117 vsl->purge(chunk_manager);
118 dec_reserved_words(vsl->reserved_words());
119 dec_committed_words(vsl->committed_words());
120 dec_virtual_space_count();
121 delete vsl;
122 num_purged_nodes ++;
123 } else {
124 prev_vsl = vsl;
125 }
126 }
127
128 // Verify list
129#ifdef ASSERT
130 if (num_purged_nodes > 0) {
131 verify(false);
132 }
133#endif
134}
135
136
137// This function looks at the mmap regions in the metaspace without locking.
138// The chunks are added with store ordering and not deleted except for at
139// unloading time during a safepoint.
140VirtualSpaceNode* VirtualSpaceList::find_enclosing_space(const void* ptr) {
141 // List should be stable enough to use an iterator here because removing virtual
142 // space nodes is only allowed at a safepoint.
143 if (is_within_envelope((address)ptr)) {
144 VirtualSpaceListIterator iter(virtual_space_list());
145 while (iter.repeat()) {
146 VirtualSpaceNode* vsn = iter.get_next();
147 if (vsn->contains(ptr)) {
148 return vsn;
149 }
150 }
151 }
152 return NULL;
153}
154
155void VirtualSpaceList::retire_current_virtual_space() {
156 assert_lock_strong(MetaspaceExpand_lock);
157
158 VirtualSpaceNode* vsn = current_virtual_space();
159
160 ChunkManager* cm = is_class() ? Metaspace::chunk_manager_class() :
161 Metaspace::chunk_manager_metadata();
162
163 vsn->retire(cm);
164}
165
166VirtualSpaceList::VirtualSpaceList(size_t word_size) :
167 _virtual_space_list(NULL),
168 _current_virtual_space(NULL),
169 _is_class(false),
170 _reserved_words(0),
171 _committed_words(0),
172 _virtual_space_count(0),
173 _envelope_lo((address)max_uintx),
174 _envelope_hi(NULL) {
175 MutexLocker cl(MetaspaceExpand_lock, Mutex::_no_safepoint_check_flag);
176 create_new_virtual_space(word_size);
177}
178
179VirtualSpaceList::VirtualSpaceList(ReservedSpace rs) :
180 _virtual_space_list(NULL),
181 _current_virtual_space(NULL),
182 _is_class(true),
183 _reserved_words(0),
184 _committed_words(0),
185 _virtual_space_count(0),
186 _envelope_lo((address)max_uintx),
187 _envelope_hi(NULL) {
188 MutexLocker cl(MetaspaceExpand_lock, Mutex::_no_safepoint_check_flag);
189 VirtualSpaceNode* class_entry = new VirtualSpaceNode(is_class(), rs);
190 bool succeeded = class_entry->initialize();
191 if (succeeded) {
192 expand_envelope_to_include_node(class_entry);
193 // ensure lock-free iteration sees fully initialized node
194 OrderAccess::storestore();
195 link_vs(class_entry);
196 }
197}
198
199size_t VirtualSpaceList::free_bytes() {
200 return current_virtual_space()->free_words_in_vs() * BytesPerWord;
201}
202
203// Allocate another meta virtual space and add it to the list.
204bool VirtualSpaceList::create_new_virtual_space(size_t vs_word_size) {
205 assert_lock_strong(MetaspaceExpand_lock);
206
207 if (is_class()) {
208 assert(false, "We currently don't support more than one VirtualSpace for"
209 " the compressed class space. The initialization of the"
210 " CCS uses another code path and should not hit this path.");
211 return false;
212 }
213
214 if (vs_word_size == 0) {
215 assert(false, "vs_word_size should always be at least _reserve_alignment large.");
216 return false;
217 }
218
219 // Reserve the space
220 size_t vs_byte_size = vs_word_size * BytesPerWord;
221 assert_is_aligned(vs_byte_size, Metaspace::reserve_alignment());
222
223 // Allocate the meta virtual space and initialize it.
224 VirtualSpaceNode* new_entry = new VirtualSpaceNode(is_class(), vs_byte_size);
225 if (!new_entry->initialize()) {
226 delete new_entry;
227 return false;
228 } else {
229 assert(new_entry->reserved_words() == vs_word_size,
230 "Reserved memory size differs from requested memory size");
231 expand_envelope_to_include_node(new_entry);
232 // ensure lock-free iteration sees fully initialized node
233 OrderAccess::storestore();
234 link_vs(new_entry);
235 DEBUG_ONLY(Atomic::inc(&g_internal_statistics.num_vsnodes_created));
236 return true;
237 }
238
239 DEBUG_ONLY(verify(false);)
240
241}
242
243void VirtualSpaceList::link_vs(VirtualSpaceNode* new_entry) {
244 if (virtual_space_list() == NULL) {
245 set_virtual_space_list(new_entry);
246 } else {
247 current_virtual_space()->set_next(new_entry);
248 }
249 set_current_virtual_space(new_entry);
250 inc_reserved_words(new_entry->reserved_words());
251 inc_committed_words(new_entry->committed_words());
252 inc_virtual_space_count();
253#ifdef ASSERT
254 new_entry->mangle();
255#endif
256 LogTarget(Trace, gc, metaspace) lt;
257 if (lt.is_enabled()) {
258 LogStream ls(lt);
259 VirtualSpaceNode* vsl = current_virtual_space();
260 ResourceMark rm;
261 vsl->print_on(&ls);
262 }
263}
264
265bool VirtualSpaceList::expand_node_by(VirtualSpaceNode* node,
266 size_t min_words,
267 size_t preferred_words) {
268 size_t before = node->committed_words();
269
270 bool result = node->expand_by(min_words, preferred_words);
271
272 size_t after = node->committed_words();
273
274 // after and before can be the same if the memory was pre-committed.
275 assert(after >= before, "Inconsistency");
276 inc_committed_words(after - before);
277
278 return result;
279}
280
281bool VirtualSpaceList::expand_by(size_t min_words, size_t preferred_words) {
282 assert_is_aligned(min_words, Metaspace::commit_alignment_words());
283 assert_is_aligned(preferred_words, Metaspace::commit_alignment_words());
284 assert(min_words <= preferred_words, "Invalid arguments");
285
286 const char* const class_or_not = (is_class() ? "class" : "non-class");
287
288 if (!MetaspaceGC::can_expand(min_words, this->is_class())) {
289 log_trace(gc, metaspace, freelist)("Cannot expand %s virtual space list.",
290 class_or_not);
291 return false;
292 }
293
294 size_t allowed_expansion_words = MetaspaceGC::allowed_expansion();
295 if (allowed_expansion_words < min_words) {
296 log_trace(gc, metaspace, freelist)("Cannot expand %s virtual space list (must try gc first).",
297 class_or_not);
298 return false;
299 }
300
301 size_t max_expansion_words = MIN2(preferred_words, allowed_expansion_words);
302
303 // Commit more memory from the the current virtual space.
304 bool vs_expanded = expand_node_by(current_virtual_space(),
305 min_words,
306 max_expansion_words);
307 if (vs_expanded) {
308 log_trace(gc, metaspace, freelist)("Expanded %s virtual space list.",
309 class_or_not);
310 return true;
311 }
312 log_trace(gc, metaspace, freelist)("%s virtual space list: retire current node.",
313 class_or_not);
314 retire_current_virtual_space();
315
316 // Get another virtual space.
317 size_t grow_vs_words = MAX2((size_t)VirtualSpaceSize, preferred_words);
318 grow_vs_words = align_up(grow_vs_words, Metaspace::reserve_alignment_words());
319
320 if (create_new_virtual_space(grow_vs_words)) {
321 if (current_virtual_space()->is_pre_committed()) {
322 // The memory was pre-committed, so we are done here.
323 assert(min_words <= current_virtual_space()->committed_words(),
324 "The new VirtualSpace was pre-committed, so it"
325 "should be large enough to fit the alloc request.");
326 return true;
327 }
328
329 return expand_node_by(current_virtual_space(),
330 min_words,
331 max_expansion_words);
332 }
333
334 return false;
335}
336
337// Given a chunk, calculate the largest possible padding space which
338// could be required when allocating it.
339static size_t largest_possible_padding_size_for_chunk(size_t chunk_word_size, bool is_class) {
340 const ChunkIndex chunk_type = get_chunk_type_by_size(chunk_word_size, is_class);
341 if (chunk_type != HumongousIndex) {
342 // Normal, non-humongous chunks are allocated at chunk size
343 // boundaries, so the largest padding space required would be that
344 // minus the smallest chunk size.
345 const size_t smallest_chunk_size = is_class ? ClassSpecializedChunk : SpecializedChunk;
346 return chunk_word_size - smallest_chunk_size;
347 } else {
348 // Humongous chunks are allocated at smallest-chunksize
349 // boundaries, so there is no padding required.
350 return 0;
351 }
352}
353
354
355Metachunk* VirtualSpaceList::get_new_chunk(size_t chunk_word_size, size_t suggested_commit_granularity) {
356
357 // Allocate a chunk out of the current virtual space.
358 Metachunk* next = current_virtual_space()->get_chunk_vs(chunk_word_size);
359
360 if (next != NULL) {
361 return next;
362 }
363
364 // The expand amount is currently only determined by the requested sizes
365 // and not how much committed memory is left in the current virtual space.
366
367 // We must have enough space for the requested size and any
368 // additional reqired padding chunks.
369 const size_t size_for_padding = largest_possible_padding_size_for_chunk(chunk_word_size, this->is_class());
370
371 size_t min_word_size = align_up(chunk_word_size + size_for_padding, Metaspace::commit_alignment_words());
372 size_t preferred_word_size = align_up(suggested_commit_granularity, Metaspace::commit_alignment_words());
373 if (min_word_size >= preferred_word_size) {
374 // Can happen when humongous chunks are allocated.
375 preferred_word_size = min_word_size;
376 }
377
378 bool expanded = expand_by(min_word_size, preferred_word_size);
379 if (expanded) {
380 next = current_virtual_space()->get_chunk_vs(chunk_word_size);
381 assert(next != NULL, "The allocation was expected to succeed after the expansion");
382 }
383
384 return next;
385}
386
387void VirtualSpaceList::print_on(outputStream* st, size_t scale) const {
388 st->print_cr(SIZE_FORMAT " nodes, current node: " PTR_FORMAT,
389 _virtual_space_count, p2i(_current_virtual_space));
390 VirtualSpaceListIterator iter(virtual_space_list());
391 while (iter.repeat()) {
392 st->cr();
393 VirtualSpaceNode* node = iter.get_next();
394 node->print_on(st, scale);
395 }
396}
397
398void VirtualSpaceList::print_map(outputStream* st) const {
399 VirtualSpaceNode* list = virtual_space_list();
400 VirtualSpaceListIterator iter(list);
401 unsigned i = 0;
402 while (iter.repeat()) {
403 st->print_cr("Node %u:", i);
404 VirtualSpaceNode* node = iter.get_next();
405 node->print_map(st, this->is_class());
406 i ++;
407 }
408}
409
410// Given a node, expand range such that it includes the node.
411void VirtualSpaceList::expand_envelope_to_include_node(const VirtualSpaceNode* node) {
412 _envelope_lo = MIN2(_envelope_lo, (address)node->low_boundary());
413 _envelope_hi = MAX2(_envelope_hi, (address)node->high_boundary());
414}
415
416
417#ifdef ASSERT
418void VirtualSpaceList::verify(bool slow) {
419 VirtualSpaceNode* list = virtual_space_list();
420 VirtualSpaceListIterator iter(list);
421 size_t reserved = 0;
422 size_t committed = 0;
423 size_t node_count = 0;
424 while (iter.repeat()) {
425 VirtualSpaceNode* node = iter.get_next();
426 if (slow) {
427 node->verify(true);
428 }
429 // Check that the node resides fully within our envelope.
430 assert((address)node->low_boundary() >= _envelope_lo && (address)node->high_boundary() <= _envelope_hi,
431 "Node " SIZE_FORMAT " [" PTR_FORMAT ", " PTR_FORMAT ") outside envelope [" PTR_FORMAT ", " PTR_FORMAT ").",
432 node_count, p2i(node->low_boundary()), p2i(node->high_boundary()), p2i(_envelope_lo), p2i(_envelope_hi));
433 reserved += node->reserved_words();
434 committed += node->committed_words();
435 node_count ++;
436 }
437 assert(reserved == reserved_words() && committed == committed_words() && node_count == _virtual_space_count,
438 "Mismatch: reserved real: " SIZE_FORMAT " expected: " SIZE_FORMAT
439 ", committed real: " SIZE_FORMAT " expected: " SIZE_FORMAT
440 ", node count real: " SIZE_FORMAT " expected: " SIZE_FORMAT ".",
441 reserved, reserved_words(), committed, committed_words(),
442 node_count, _virtual_space_count);
443}
444#endif // ASSERT
445
446} // namespace metaspace
447
448