1 /*
2 * Copyright (c) 2013, 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.
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 #include "precompiled.hpp"
25
26 #include "logging/log.hpp"
27 #include "memory/metaspace.hpp"
28 #include "runtime/os.hpp"
29 #include "runtime/threadCritical.hpp"
30 #include "services/memTracker.hpp"
31 #include "services/threadStackTracker.hpp"
32 #include "services/virtualMemoryTracker.hpp"
33 #include "utilities/ostream.hpp"
34
35 size_t VirtualMemorySummary::_snapshot[CALC_OBJ_SIZE_IN_TYPE(VirtualMemorySnapshot, size_t)];
36
initialize()37 void VirtualMemorySummary::initialize() {
38 assert(sizeof(_snapshot) >= sizeof(VirtualMemorySnapshot), "Sanity Check");
39 // Use placement operator new to initialize static data area.
40 ::new ((void*)_snapshot) VirtualMemorySnapshot();
41 }
42
snapshot(VirtualMemorySnapshot * s)43 void VirtualMemorySummary::snapshot(VirtualMemorySnapshot* s) {
44 // Only if thread stack is backed by virtual memory
45 if (ThreadStackTracker::track_as_vm()) {
46 // Snapshot current thread stacks
47 VirtualMemoryTracker::snapshot_thread_stacks();
48 }
49 as_snapshot()->copy_to(s);
50 }
51
52 SortedLinkedList<ReservedMemoryRegion, compare_reserved_region_base>* VirtualMemoryTracker::_reserved_regions;
53
compare_committed_region(const CommittedMemoryRegion & r1,const CommittedMemoryRegion & r2)54 int compare_committed_region(const CommittedMemoryRegion& r1, const CommittedMemoryRegion& r2) {
55 return r1.compare(r2);
56 }
57
compare_reserved_region_base(const ReservedMemoryRegion & r1,const ReservedMemoryRegion & r2)58 int compare_reserved_region_base(const ReservedMemoryRegion& r1, const ReservedMemoryRegion& r2) {
59 return r1.compare(r2);
60 }
61
is_mergeable_with(CommittedMemoryRegion * rgn,address addr,size_t size,const NativeCallStack & stack)62 static bool is_mergeable_with(CommittedMemoryRegion* rgn, address addr, size_t size, const NativeCallStack& stack) {
63 return rgn->adjacent_to(addr, size) && rgn->call_stack()->equals(stack);
64 }
65
is_same_as(CommittedMemoryRegion * rgn,address addr,size_t size,const NativeCallStack & stack)66 static bool is_same_as(CommittedMemoryRegion* rgn, address addr, size_t size, const NativeCallStack& stack) {
67 // It would have made sense to use rgn->equals(...), but equals returns true for overlapping regions.
68 return rgn->same_region(addr, size) && rgn->call_stack()->equals(stack);
69 }
70
find_preceding_node_from(LinkedListNode<CommittedMemoryRegion> * from,address addr)71 static LinkedListNode<CommittedMemoryRegion>* find_preceding_node_from(LinkedListNode<CommittedMemoryRegion>* from, address addr) {
72 LinkedListNode<CommittedMemoryRegion>* preceding = NULL;
73
74 for (LinkedListNode<CommittedMemoryRegion>* node = from; node != NULL; node = node->next()) {
75 CommittedMemoryRegion* rgn = node->data();
76
77 // We searched past the region start.
78 if (rgn->end() > addr) {
79 break;
80 }
81
82 preceding = node;
83 }
84
85 return preceding;
86 }
87
try_merge_with(LinkedListNode<CommittedMemoryRegion> * node,address addr,size_t size,const NativeCallStack & stack)88 static bool try_merge_with(LinkedListNode<CommittedMemoryRegion>* node, address addr, size_t size, const NativeCallStack& stack) {
89 if (node != NULL) {
90 CommittedMemoryRegion* rgn = node->data();
91
92 if (is_mergeable_with(rgn, addr, size, stack)) {
93 rgn->expand_region(addr, size);
94 return true;
95 }
96 }
97
98 return false;
99 }
100
try_merge_with(LinkedListNode<CommittedMemoryRegion> * node,LinkedListNode<CommittedMemoryRegion> * other)101 static bool try_merge_with(LinkedListNode<CommittedMemoryRegion>* node, LinkedListNode<CommittedMemoryRegion>* other) {
102 if (other == NULL) {
103 return false;
104 }
105
106 CommittedMemoryRegion* rgn = other->data();
107 return try_merge_with(node, rgn->base(), rgn->size(), *rgn->call_stack());
108 }
109
add_committed_region(address addr,size_t size,const NativeCallStack & stack)110 bool ReservedMemoryRegion::add_committed_region(address addr, size_t size, const NativeCallStack& stack) {
111 assert(addr != NULL, "Invalid address");
112 assert(size > 0, "Invalid size");
113 assert(contain_region(addr, size), "Not contain this region");
114
115 // Find the region that fully precedes the [addr, addr + size) region.
116 LinkedListNode<CommittedMemoryRegion>* prev = find_preceding_node_from(_committed_regions.head(), addr);
117 LinkedListNode<CommittedMemoryRegion>* next = (prev != NULL ? prev->next() : _committed_regions.head());
118
119 if (next != NULL) {
120 // Ignore request if region already exists.
121 if (is_same_as(next->data(), addr, size, stack)) {
122 return true;
123 }
124
125 // The new region is after prev, and either overlaps with the
126 // next region (and maybe more regions), or overlaps with no region.
127 if (next->data()->overlap_region(addr, size)) {
128 // Remove _all_ overlapping regions, and parts of regions,
129 // in preparation for the addition of this new region.
130 remove_uncommitted_region(addr, size);
131
132 // The remove could have split a region into two and created a
133 // new prev region. Need to reset the prev and next pointers.
134 prev = find_preceding_node_from((prev != NULL ? prev : _committed_regions.head()), addr);
135 next = (prev != NULL ? prev->next() : _committed_regions.head());
136 }
137 }
138
139 // At this point the previous overlapping regions have been
140 // cleared, and the full region is guaranteed to be inserted.
141 VirtualMemorySummary::record_committed_memory(size, flag());
142
143 // Try to merge with prev and possibly next.
144 if (try_merge_with(prev, addr, size, stack)) {
145 if (try_merge_with(prev, next)) {
146 // prev was expanded to contain the new region
147 // and next, need to remove next from the list
148 _committed_regions.remove_after(prev);
149 }
150
151 return true;
152 }
153
154 // Didn't merge with prev, try with next.
155 if (try_merge_with(next, addr, size, stack)) {
156 return true;
157 }
158
159 // Couldn't merge with any regions - create a new region.
160 return add_committed_region(CommittedMemoryRegion(addr, size, stack));
161 }
162
remove_uncommitted_region(LinkedListNode<CommittedMemoryRegion> * node,address addr,size_t size)163 bool ReservedMemoryRegion::remove_uncommitted_region(LinkedListNode<CommittedMemoryRegion>* node,
164 address addr, size_t size) {
165 assert(addr != NULL, "Invalid address");
166 assert(size > 0, "Invalid size");
167
168 CommittedMemoryRegion* rgn = node->data();
169 assert(rgn->contain_region(addr, size), "Has to be contained");
170 assert(!rgn->same_region(addr, size), "Can not be the same region");
171
172 if (rgn->base() == addr ||
173 rgn->end() == addr + size) {
174 rgn->exclude_region(addr, size);
175 return true;
176 } else {
177 // split this region
178 address top =rgn->end();
179 // use this region for lower part
180 size_t exclude_size = rgn->end() - addr;
181 rgn->exclude_region(addr, exclude_size);
182
183 // higher part
184 address high_base = addr + size;
185 size_t high_size = top - high_base;
186
187 CommittedMemoryRegion high_rgn(high_base, high_size, *rgn->call_stack());
188 LinkedListNode<CommittedMemoryRegion>* high_node = _committed_regions.add(high_rgn);
189 assert(high_node == NULL || node->next() == high_node, "Should be right after");
190 return (high_node != NULL);
191 }
192
193 return false;
194 }
195
remove_uncommitted_region(address addr,size_t sz)196 bool ReservedMemoryRegion::remove_uncommitted_region(address addr, size_t sz) {
197 assert(addr != NULL, "Invalid address");
198 assert(sz > 0, "Invalid size");
199
200 CommittedMemoryRegion del_rgn(addr, sz, *call_stack());
201 address end = addr + sz;
202
203 LinkedListNode<CommittedMemoryRegion>* head = _committed_regions.head();
204 LinkedListNode<CommittedMemoryRegion>* prev = NULL;
205 CommittedMemoryRegion* crgn;
206
207 while (head != NULL) {
208 crgn = head->data();
209
210 if (crgn->same_region(addr, sz)) {
211 VirtualMemorySummary::record_uncommitted_memory(crgn->size(), flag());
212 _committed_regions.remove_after(prev);
213 return true;
214 }
215
216 // del_rgn contains crgn
217 if (del_rgn.contain_region(crgn->base(), crgn->size())) {
218 VirtualMemorySummary::record_uncommitted_memory(crgn->size(), flag());
219 head = head->next();
220 _committed_regions.remove_after(prev);
221 continue; // don't update head or prev
222 }
223
224 // Found addr in the current crgn. There are 2 subcases:
225 if (crgn->contain_address(addr)) {
226
227 // (1) Found addr+size in current crgn as well. (del_rgn is contained in crgn)
228 if (crgn->contain_address(end - 1)) {
229 VirtualMemorySummary::record_uncommitted_memory(sz, flag());
230 return remove_uncommitted_region(head, addr, sz); // done!
231 } else {
232 // (2) Did not find del_rgn's end in crgn.
233 size_t size = crgn->end() - del_rgn.base();
234 crgn->exclude_region(addr, size);
235 VirtualMemorySummary::record_uncommitted_memory(size, flag());
236 }
237
238 } else if (crgn->contain_address(end - 1)) {
239 // Found del_rgn's end, but not its base addr.
240 size_t size = del_rgn.end() - crgn->base();
241 crgn->exclude_region(crgn->base(), size);
242 VirtualMemorySummary::record_uncommitted_memory(size, flag());
243 return true; // should be done if the list is sorted properly!
244 }
245
246 prev = head;
247 head = head->next();
248 }
249
250 return true;
251 }
252
move_committed_regions(address addr,ReservedMemoryRegion & rgn)253 void ReservedMemoryRegion::move_committed_regions(address addr, ReservedMemoryRegion& rgn) {
254 assert(addr != NULL, "Invalid address");
255
256 // split committed regions
257 LinkedListNode<CommittedMemoryRegion>* head =
258 _committed_regions.head();
259 LinkedListNode<CommittedMemoryRegion>* prev = NULL;
260
261 while (head != NULL) {
262 if (head->data()->base() >= addr) {
263 break;
264 }
265 prev = head;
266 head = head->next();
267 }
268
269 if (head != NULL) {
270 if (prev != NULL) {
271 prev->set_next(head->next());
272 } else {
273 _committed_regions.set_head(NULL);
274 }
275 }
276
277 rgn._committed_regions.set_head(head);
278 }
279
committed_size() const280 size_t ReservedMemoryRegion::committed_size() const {
281 size_t committed = 0;
282 LinkedListNode<CommittedMemoryRegion>* head =
283 _committed_regions.head();
284 while (head != NULL) {
285 committed += head->data()->size();
286 head = head->next();
287 }
288 return committed;
289 }
290
set_flag(MEMFLAGS f)291 void ReservedMemoryRegion::set_flag(MEMFLAGS f) {
292 assert((flag() == mtNone || flag() == f),
293 "Overwrite memory type for region [" INTPTR_FORMAT "-" INTPTR_FORMAT "), %u->%u.",
294 p2i(base()), p2i(end()), (unsigned)flag(), (unsigned)f);
295 if (flag() != f) {
296 VirtualMemorySummary::move_reserved_memory(flag(), f, size());
297 VirtualMemorySummary::move_committed_memory(flag(), f, committed_size());
298 _flag = f;
299 }
300 }
301
thread_stack_uncommitted_bottom() const302 address ReservedMemoryRegion::thread_stack_uncommitted_bottom() const {
303 assert(flag() == mtThreadStack, "Only for thread stack");
304 LinkedListNode<CommittedMemoryRegion>* head = _committed_regions.head();
305 address bottom = base();
306 address top = base() + size();
307 while (head != NULL) {
308 address committed_top = head->data()->base() + head->data()->size();
309 if (committed_top < top) {
310 // committed stack guard pages, skip them
311 bottom = head->data()->base() + head->data()->size();
312 head = head->next();
313 } else {
314 assert(top == committed_top, "Sanity");
315 break;
316 }
317 }
318
319 return bottom;
320 }
321
initialize(NMT_TrackingLevel level)322 bool VirtualMemoryTracker::initialize(NMT_TrackingLevel level) {
323 if (level >= NMT_summary) {
324 VirtualMemorySummary::initialize();
325 }
326 return true;
327 }
328
late_initialize(NMT_TrackingLevel level)329 bool VirtualMemoryTracker::late_initialize(NMT_TrackingLevel level) {
330 if (level >= NMT_summary) {
331 _reserved_regions = new (std::nothrow, ResourceObj::C_HEAP, mtNMT)
332 SortedLinkedList<ReservedMemoryRegion, compare_reserved_region_base>();
333 return (_reserved_regions != NULL);
334 }
335 return true;
336 }
337
add_reserved_region(address base_addr,size_t size,const NativeCallStack & stack,MEMFLAGS flag)338 bool VirtualMemoryTracker::add_reserved_region(address base_addr, size_t size,
339 const NativeCallStack& stack, MEMFLAGS flag) {
340 assert(base_addr != NULL, "Invalid address");
341 assert(size > 0, "Invalid size");
342 assert(_reserved_regions != NULL, "Sanity check");
343 ReservedMemoryRegion rgn(base_addr, size, stack, flag);
344 ReservedMemoryRegion* reserved_rgn = _reserved_regions->find(rgn);
345
346 log_debug(nmt)("Add reserved region \'%s\' (" INTPTR_FORMAT ", " SIZE_FORMAT ")",
347 rgn.flag_name(), p2i(rgn.base()), rgn.size());
348 if (reserved_rgn == NULL) {
349 VirtualMemorySummary::record_reserved_memory(size, flag);
350 return _reserved_regions->add(rgn) != NULL;
351 } else {
352 // Deal with recursive reservation
353 // os::reserve_memory() -> pd_reserve_memory() -> os::reserve_memory()
354 // See JDK-8198226.
355 if (reserved_rgn->same_region(base_addr, size) &&
356 (reserved_rgn->flag() == flag || reserved_rgn->flag() == mtNone)) {
357 reserved_rgn->set_call_stack(stack);
358 reserved_rgn->set_flag(flag);
359 return true;
360 } else {
361 assert(reserved_rgn->overlap_region(base_addr, size), "Must be");
362
363 // Overlapped reservation.
364 // It can happen when the regions are thread stacks, as JNI
365 // thread does not detach from VM before exits, and leads to
366 // leak JavaThread object
367 if (reserved_rgn->flag() == mtThreadStack) {
368 guarantee(!CheckJNICalls, "Attached JNI thread exited without being detached");
369 // Overwrite with new region
370
371 // Release old region
372 VirtualMemorySummary::record_uncommitted_memory(reserved_rgn->committed_size(), reserved_rgn->flag());
373 VirtualMemorySummary::record_released_memory(reserved_rgn->size(), reserved_rgn->flag());
374
375 // Add new region
376 VirtualMemorySummary::record_reserved_memory(rgn.size(), flag);
377
378 *reserved_rgn = rgn;
379 return true;
380 }
381
382 // CDS mapping region.
383 // CDS reserves the whole region for mapping CDS archive, then maps each section into the region.
384 // NMT reports CDS as a whole.
385 if (reserved_rgn->flag() == mtClassShared) {
386 log_debug(nmt)("CDS reserved region \'%s\' as a whole (" INTPTR_FORMAT ", " SIZE_FORMAT ")",
387 reserved_rgn->flag_name(), p2i(reserved_rgn->base()), reserved_rgn->size());
388 assert(reserved_rgn->contain_region(base_addr, size), "Reserved CDS region should contain this mapping region");
389 return true;
390 }
391
392 // Mapped CDS string region.
393 // The string region(s) is part of the java heap.
394 if (reserved_rgn->flag() == mtJavaHeap) {
395 log_debug(nmt)("CDS reserved region \'%s\' as a whole (" INTPTR_FORMAT ", " SIZE_FORMAT ")",
396 reserved_rgn->flag_name(), p2i(reserved_rgn->base()), reserved_rgn->size());
397 assert(reserved_rgn->contain_region(base_addr, size), "Reserved heap region should contain this mapping region");
398 return true;
399 }
400
401 // Print some more details. Don't use UL here to avoid circularities.
402 #ifdef ASSERT
403 tty->print_cr("Error: existing region: [" INTPTR_FORMAT "-" INTPTR_FORMAT "), flag %u.\n"
404 " new region: [" INTPTR_FORMAT "-" INTPTR_FORMAT "), flag %u.",
405 p2i(reserved_rgn->base()), p2i(reserved_rgn->end()), (unsigned)reserved_rgn->flag(),
406 p2i(base_addr), p2i(base_addr + size), (unsigned)flag);
407 #endif
408 ShouldNotReachHere();
409 return false;
410 }
411 }
412 }
413
set_reserved_region_type(address addr,MEMFLAGS flag)414 void VirtualMemoryTracker::set_reserved_region_type(address addr, MEMFLAGS flag) {
415 assert(addr != NULL, "Invalid address");
416 assert(_reserved_regions != NULL, "Sanity check");
417
418 ReservedMemoryRegion rgn(addr, 1);
419 ReservedMemoryRegion* reserved_rgn = _reserved_regions->find(rgn);
420 if (reserved_rgn != NULL) {
421 assert(reserved_rgn->contain_address(addr), "Containment");
422 if (reserved_rgn->flag() != flag) {
423 assert(reserved_rgn->flag() == mtNone, "Overwrite memory type (should be mtNone, is: \"%s\")",
424 NMTUtil::flag_to_name(reserved_rgn->flag()));
425 reserved_rgn->set_flag(flag);
426 }
427 }
428 }
429
add_committed_region(address addr,size_t size,const NativeCallStack & stack)430 bool VirtualMemoryTracker::add_committed_region(address addr, size_t size,
431 const NativeCallStack& stack) {
432 assert(addr != NULL, "Invalid address");
433 assert(size > 0, "Invalid size");
434 assert(_reserved_regions != NULL, "Sanity check");
435
436 ReservedMemoryRegion rgn(addr, size);
437 ReservedMemoryRegion* reserved_rgn = _reserved_regions->find(rgn);
438
439 if (reserved_rgn == NULL) {
440 log_debug(nmt)("Add committed region \'%s\', No reserved region found for (" INTPTR_FORMAT ", " SIZE_FORMAT ")",
441 rgn.flag_name(), p2i(rgn.base()), rgn.size());
442 }
443 assert(reserved_rgn != NULL, "Add committed region, No reserved region found");
444 assert(reserved_rgn->contain_region(addr, size), "Not completely contained");
445 bool result = reserved_rgn->add_committed_region(addr, size, stack);
446 log_debug(nmt)("Add committed region \'%s\'(" INTPTR_FORMAT ", " SIZE_FORMAT ") %s",
447 rgn.flag_name(), p2i(rgn.base()), rgn.size(), (result ? "Succeeded" : "Failed"));
448 return result;
449 }
450
remove_uncommitted_region(address addr,size_t size)451 bool VirtualMemoryTracker::remove_uncommitted_region(address addr, size_t size) {
452 assert(addr != NULL, "Invalid address");
453 assert(size > 0, "Invalid size");
454 assert(_reserved_regions != NULL, "Sanity check");
455
456 ReservedMemoryRegion rgn(addr, size);
457 ReservedMemoryRegion* reserved_rgn = _reserved_regions->find(rgn);
458 assert(reserved_rgn != NULL, "No reserved region (" INTPTR_FORMAT ", " SIZE_FORMAT ")", p2i(addr), size);
459 assert(reserved_rgn->contain_region(addr, size), "Not completely contained");
460 const char* flag_name = reserved_rgn->flag_name(); // after remove, info is not complete
461 bool result = reserved_rgn->remove_uncommitted_region(addr, size);
462 log_debug(nmt)("Removed uncommitted region \'%s\' (" INTPTR_FORMAT ", " SIZE_FORMAT ") %s",
463 flag_name, p2i(addr), size, (result ? " Succeeded" : "Failed"));
464 return result;
465 }
466
remove_released_region(ReservedMemoryRegion * rgn)467 bool VirtualMemoryTracker::remove_released_region(ReservedMemoryRegion* rgn) {
468 assert(rgn != NULL, "Sanity check");
469 assert(_reserved_regions != NULL, "Sanity check");
470
471 // uncommit regions within the released region
472 ReservedMemoryRegion backup(*rgn);
473 bool result = rgn->remove_uncommitted_region(rgn->base(), rgn->size());
474 log_debug(nmt)("Remove uncommitted region \'%s\' (" INTPTR_FORMAT ", " SIZE_FORMAT ") %s",
475 backup.flag_name(), p2i(backup.base()), backup.size(), (result ? "Succeeded" : "Failed"));
476 if (!result) {
477 return false;
478 }
479
480 VirtualMemorySummary::record_released_memory(rgn->size(), rgn->flag());
481 result = _reserved_regions->remove(*rgn);
482 log_debug(nmt)("Removed region \'%s\' (" INTPTR_FORMAT ", " SIZE_FORMAT ") from _resvered_regions %s" ,
483 backup.flag_name(), p2i(backup.base()), backup.size(), (result ? "Succeeded" : "Failed"));
484 return result;
485 }
486
remove_released_region(address addr,size_t size)487 bool VirtualMemoryTracker::remove_released_region(address addr, size_t size) {
488 assert(addr != NULL, "Invalid address");
489 assert(size > 0, "Invalid size");
490 assert(_reserved_regions != NULL, "Sanity check");
491
492 ReservedMemoryRegion rgn(addr, size);
493 ReservedMemoryRegion* reserved_rgn = _reserved_regions->find(rgn);
494
495 if (reserved_rgn == NULL) {
496 log_debug(nmt)("No reserved region found for (" INTPTR_FORMAT ", " SIZE_FORMAT ")!",
497 p2i(rgn.base()), rgn.size());
498 }
499 assert(reserved_rgn != NULL, "No reserved region");
500 if (reserved_rgn->same_region(addr, size)) {
501 return remove_released_region(reserved_rgn);
502 }
503
504 // uncommit regions within the released region
505 if (!reserved_rgn->remove_uncommitted_region(addr, size)) {
506 return false;
507 }
508
509 if (reserved_rgn->flag() == mtClassShared &&
510 reserved_rgn->contain_region(addr, size)) {
511 // This is an unmapped CDS region, which is part of the reserved shared
512 // memory region.
513 // See special handling in VirtualMemoryTracker::add_reserved_region also.
514 return true;
515 }
516
517 VirtualMemorySummary::record_released_memory(size, reserved_rgn->flag());
518
519 assert(reserved_rgn->contain_region(addr, size), "Not completely contained");
520 if (reserved_rgn->base() == addr ||
521 reserved_rgn->end() == addr + size) {
522 reserved_rgn->exclude_region(addr, size);
523 return true;
524 } else {
525 address top = reserved_rgn->end();
526 address high_base = addr + size;
527 ReservedMemoryRegion high_rgn(high_base, top - high_base,
528 *reserved_rgn->call_stack(), reserved_rgn->flag());
529
530 // use original region for lower region
531 reserved_rgn->exclude_region(addr, top - addr);
532 LinkedListNode<ReservedMemoryRegion>* new_rgn = _reserved_regions->add(high_rgn);
533 if (new_rgn == NULL) {
534 return false;
535 } else {
536 reserved_rgn->move_committed_regions(addr, *new_rgn->data());
537 return true;
538 }
539 }
540 }
541
542 // Given an existing memory mapping registered with NMT, split the mapping in
543 // two. The newly created two mappings will be registered under the call
544 // stack and the memory flags of the original section.
split_reserved_region(address addr,size_t size,size_t split)545 bool VirtualMemoryTracker::split_reserved_region(address addr, size_t size, size_t split) {
546
547 ReservedMemoryRegion rgn(addr, size);
548 ReservedMemoryRegion* reserved_rgn = _reserved_regions->find(rgn);
549 assert(reserved_rgn->same_region(addr, size), "Must be identical region");
550 assert(reserved_rgn != NULL, "No reserved region");
551 assert(reserved_rgn->committed_size() == 0, "Splitting committed region?");
552
553 NativeCallStack original_stack = *reserved_rgn->call_stack();
554 MEMFLAGS original_flags = reserved_rgn->flag();
555
556 const char* name = reserved_rgn->flag_name();
557 remove_released_region(reserved_rgn);
558 log_debug(nmt)("Split region \'%s\' (" INTPTR_FORMAT ", " SIZE_FORMAT ") with size " SIZE_FORMAT,
559 name, p2i(rgn.base()), rgn.size(), split);
560 // Now, create two new regions.
561 add_reserved_region(addr, split, original_stack, original_flags);
562 add_reserved_region(addr + split, size - split, original_stack, original_flags);
563
564 return true;
565 }
566
567
568 // Iterate the range, find committed region within its bound.
569 class RegionIterator : public StackObj {
570 private:
571 const address _start;
572 const size_t _size;
573
574 address _current_start;
575 size_t _current_size;
576 public:
RegionIterator(address start,size_t size)577 RegionIterator(address start, size_t size) :
578 _start(start), _size(size), _current_start(start), _current_size(size) {
579 }
580
581 // return true if committed region is found
582 bool next_committed(address& start, size_t& size);
583 private:
end() const584 address end() const { return _start + _size; }
585 };
586
next_committed(address & committed_start,size_t & committed_size)587 bool RegionIterator::next_committed(address& committed_start, size_t& committed_size) {
588 if (end() <= _current_start) return false;
589
590 const size_t page_sz = os::vm_page_size();
591 assert(_current_start + _current_size == end(), "Must be");
592 if (os::committed_in_range(_current_start, _current_size, committed_start, committed_size)) {
593 assert(committed_start != NULL, "Must be");
594 assert(committed_size > 0 && is_aligned(committed_size, os::vm_page_size()), "Must be");
595
596 size_t remaining_size = (_current_start + _current_size) - (committed_start + committed_size);
597 _current_start = committed_start + committed_size;
598 _current_size = remaining_size;
599 return true;
600 } else {
601 return false;
602 }
603 }
604
605 // Walk all known thread stacks, snapshot their committed ranges.
606 class SnapshotThreadStackWalker : public VirtualMemoryWalker {
607 public:
SnapshotThreadStackWalker()608 SnapshotThreadStackWalker() {}
609
do_allocation_site(const ReservedMemoryRegion * rgn)610 bool do_allocation_site(const ReservedMemoryRegion* rgn) {
611 if (rgn->flag() == mtThreadStack) {
612 address stack_bottom = rgn->thread_stack_uncommitted_bottom();
613 address committed_start;
614 size_t committed_size;
615 size_t stack_size = rgn->base() + rgn->size() - stack_bottom;
616 // Align the size to work with full pages (Alpine and AIX stack top is not page aligned)
617 size_t aligned_stack_size = align_up(stack_size, os::vm_page_size());
618
619 ReservedMemoryRegion* region = const_cast<ReservedMemoryRegion*>(rgn);
620 NativeCallStack ncs; // empty stack
621
622 RegionIterator itr(stack_bottom, aligned_stack_size);
623 DEBUG_ONLY(bool found_stack = false;)
624 while (itr.next_committed(committed_start, committed_size)) {
625 assert(committed_start != NULL, "Should not be null");
626 assert(committed_size > 0, "Should not be 0");
627 // unaligned stack_size case: correct the region to fit the actual stack_size
628 if (stack_bottom + stack_size < committed_start + committed_size) {
629 committed_size = stack_bottom + stack_size - committed_start;
630 }
631 region->add_committed_region(committed_start, committed_size, ncs);
632 DEBUG_ONLY(found_stack = true;)
633 }
634 #ifdef ASSERT
635 if (!found_stack) {
636 log_debug(thread)("Thread exited without proper cleanup, may leak thread object");
637 }
638 #endif
639 }
640 return true;
641 }
642 };
643
snapshot_thread_stacks()644 void VirtualMemoryTracker::snapshot_thread_stacks() {
645 SnapshotThreadStackWalker walker;
646 walk_virtual_memory(&walker);
647 }
648
walk_virtual_memory(VirtualMemoryWalker * walker)649 bool VirtualMemoryTracker::walk_virtual_memory(VirtualMemoryWalker* walker) {
650 assert(_reserved_regions != NULL, "Sanity check");
651 ThreadCritical tc;
652 // Check that the _reserved_regions haven't been deleted.
653 if (_reserved_regions != NULL) {
654 LinkedListNode<ReservedMemoryRegion>* head = _reserved_regions->head();
655 while (head != NULL) {
656 const ReservedMemoryRegion* rgn = head->peek();
657 if (!walker->do_allocation_site(rgn)) {
658 return false;
659 }
660 head = head->next();
661 }
662 }
663 return true;
664 }
665
666 // Transition virtual memory tracking level.
transition(NMT_TrackingLevel from,NMT_TrackingLevel to)667 bool VirtualMemoryTracker::transition(NMT_TrackingLevel from, NMT_TrackingLevel to) {
668 assert (from != NMT_minimal, "cannot convert from the lowest tracking level to anything");
669 if (to == NMT_minimal) {
670 assert(from == NMT_summary || from == NMT_detail, "Just check");
671 // Clean up virtual memory tracking data structures.
672 ThreadCritical tc;
673 // Check for potential race with other thread calling transition
674 if (_reserved_regions != NULL) {
675 delete _reserved_regions;
676 _reserved_regions = NULL;
677 }
678 }
679
680 return true;
681 }
682
683 // Metaspace Support
MetaspaceSnapshot()684 MetaspaceSnapshot::MetaspaceSnapshot() {
685 for (int index = (int)Metaspace::ClassType; index < (int)Metaspace::MetadataTypeCount; index ++) {
686 Metaspace::MetadataType type = (Metaspace::MetadataType)index;
687 assert_valid_metadata_type(type);
688 _reserved_in_bytes[type] = 0;
689 _committed_in_bytes[type] = 0;
690 _used_in_bytes[type] = 0;
691 _free_in_bytes[type] = 0;
692 }
693 }
694
snapshot(Metaspace::MetadataType type,MetaspaceSnapshot & mss)695 void MetaspaceSnapshot::snapshot(Metaspace::MetadataType type, MetaspaceSnapshot& mss) {
696 assert_valid_metadata_type(type);
697
698 mss._reserved_in_bytes[type] = MetaspaceUtils::reserved_bytes(type);
699 mss._committed_in_bytes[type] = MetaspaceUtils::committed_bytes(type);
700 mss._used_in_bytes[type] = MetaspaceUtils::used_bytes(type);
701
702 // The answer to "what is free" in metaspace is complex and cannot be answered with a single number.
703 // Free as in available to all loaders? Free, pinned to one loader? For now, keep it simple.
704 mss._free_in_bytes[type] = mss._committed_in_bytes[type] - mss._used_in_bytes[type];
705 }
706
snapshot(MetaspaceSnapshot & mss)707 void MetaspaceSnapshot::snapshot(MetaspaceSnapshot& mss) {
708 snapshot(Metaspace::NonClassType, mss);
709 if (Metaspace::using_class_space()) {
710 snapshot(Metaspace::ClassType, mss);
711 }
712 }
713