1 /*
2 * Copyright (c) 1997, 2014, 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 "oops/markOop.hpp"
27 #include "oops/oop.inline.hpp"
28 #include "runtime/virtualspace.hpp"
29 #include "services/memTracker.hpp"
30
31 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
32
33 // ReservedSpace
34
35 // Dummy constructor
36 ReservedSpace::ReservedSpace() : _base(NULL), _size(0), _noaccess_prefix(0),
37 _alignment(0), _special(false), _executable(false) {
38 }
39
40 ReservedSpace::ReservedSpace(size_t size) {
41 size_t page_size = os::page_size_for_region(size, 1);
42 bool large_pages = page_size != (size_t)os::vm_page_size();
43 // Don't force the alignment to be large page aligned,
44 // since that will waste memory.
45 size_t alignment = os::vm_allocation_granularity();
46 initialize(size, alignment, large_pages, NULL, 0, false);
47 }
48
49 ReservedSpace::ReservedSpace(size_t size, size_t alignment,
50 bool large,
51 char* requested_address,
52 const size_t noaccess_prefix) {
53 initialize(size+noaccess_prefix, alignment, large, requested_address,
54 noaccess_prefix, false);
55 }
56
57 ReservedSpace::ReservedSpace(size_t size, size_t alignment,
58 bool large,
59 bool executable) {
60 initialize(size, alignment, large, NULL, 0, executable);
61 }
62
63 // Helper method.
64 static bool failed_to_reserve_as_requested(char* base, char* requested_address,
65 const size_t size, bool special)
66 {
67 if (base == requested_address || requested_address == NULL)
68 return false; // did not fail
69
70 if (base != NULL) {
71 // Different reserve address may be acceptable in other cases
72 // but for compressed oops heap should be at requested address.
73
74 // Or at least in the requested mode.
75 if ((uint64_t)base >= HeapBaseMinAddress) {
76 if ((uint64_t)requested_address + size < UnscaledOopHeapMax) {
77 // Requested unscaled mode.
78 if ((uint64_t)base + size < UnscaledOopHeapMax) {
79 // Reserved unscaled mode.
80 if (PrintCompressedOopsMode) {
81 tty->print("base: %p, req_addr: %p, base+size: %p but fulfills unscaled criteria.\n", base, requested_address, base+size);
82 }
83 return false;
84 }
85 } else if ((uint64_t)requested_address + size < OopEncodingHeapMax &&
86 (uint64_t)base + size < OopEncodingHeapMax) {
87 // Requested and reserved zerobased mode.
88 tty->print("base: %p, req_addr: %p, base+size: %p but fulfills zerobased criteria.\n", base, requested_address, base+size);
89 return false;
90 }
91 }
92
93 assert(UseCompressedOops, "currently requested address used only for compressed oops");
94 if (PrintCompressedOopsMode) {
95 tty->cr();
96 tty->print_cr("Reserved memory not at requested address: " PTR_FORMAT " vs " PTR_FORMAT, base, requested_address);
97 }
98 // OS ignored requested address. Try different address.
99 if (special) {
100 if (!os::release_memory_special(base, size)) {
101 fatal("os::release_memory_special failed");
102 }
103 } else {
104 if (!os::release_memory(base, size)) {
105 fatal("os::release_memory failed");
106 }
107 }
108 }
109 return true;
110 }
111
112 void ReservedSpace::initialize(size_t size, size_t alignment, bool large,
113 char* requested_address,
114 const size_t noaccess_prefix,
115 bool executable) {
116 const size_t granularity = os::vm_allocation_granularity();
117 assert((size & (granularity - 1)) == 0,
118 "size not aligned to os::vm_allocation_granularity()");
119 assert((alignment & (granularity - 1)) == 0,
120 "alignment not aligned to os::vm_allocation_granularity()");
121 assert(alignment == 0 || is_power_of_2((intptr_t)alignment),
122 "not a power of 2");
123
124 alignment = MAX2(alignment, (size_t)os::vm_page_size());
125
126 // Assert that if noaccess_prefix is used, it is the same as alignment.
127 assert(noaccess_prefix == 0 ||
128 noaccess_prefix == alignment, "noaccess prefix wrong");
129
130 _base = NULL;
131 _size = 0;
132 _special = false;
133 _executable = executable;
134 _alignment = 0;
135 _noaccess_prefix = 0;
136 if (size == 0) {
137 return;
138 }
139
140 // If OS doesn't support demand paging for large page memory, we need
141 // to use reserve_memory_special() to reserve and pin the entire region.
142 bool special = large && !os::can_commit_large_page_memory();
143 char* base = NULL;
144
145 if (requested_address != 0) {
146 requested_address -= noaccess_prefix; // adjust requested address
147 assert(requested_address != NULL, "huge noaccess prefix?");
148 }
149
150 if (special) {
151
152 base = os::reserve_memory_special(size, alignment, requested_address, executable);
153
154 if (base != NULL) {
155 if (failed_to_reserve_as_requested(base, requested_address, size, true)) {
156 // OS ignored requested address. Try different address.
157 return;
158 }
159 // Check alignment constraints.
160 assert((uintptr_t) base % alignment == 0,
161 err_msg("Large pages returned a non-aligned address, base: "
162 PTR_FORMAT " alignment: " PTR_FORMAT,
163 base, (void*)(uintptr_t)alignment));
164 _special = true;
165 } else {
166 // failed; try to reserve regular memory below
167 if (UseLargePages && (!FLAG_IS_DEFAULT(UseLargePages) ||
168 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) {
169 if (PrintCompressedOopsMode) {
170 tty->cr();
171 tty->print_cr("Reserve regular memory without large pages.");
172 }
173 }
174 }
175 }
176
177 if (base == NULL) {
178 // Optimistically assume that the OSes returns an aligned base pointer.
179 // When reserving a large address range, most OSes seem to align to at
180 // least 64K.
181
182 // If the memory was requested at a particular address, use
183 // os::attempt_reserve_memory_at() to avoid over mapping something
184 // important. If available space is not detected, return NULL.
185
186 if (requested_address != 0) {
187 base = os::attempt_reserve_memory_at(size, requested_address);
188 if (failed_to_reserve_as_requested(base, requested_address, size, false)) {
189 // OS ignored requested address. Try different address.
190 base = NULL;
191 }
192 } else {
193 base = os::reserve_memory(size, NULL, alignment);
194 }
195
196 if (base == NULL) return;
197
198 // Check alignment constraints
199 if ((((size_t)base + noaccess_prefix) & (alignment - 1)) != 0) {
200 // Base not aligned, retry
201 if (!os::release_memory(base, size)) fatal("os::release_memory failed");
202 // Make sure that size is aligned
203 size = align_size_up(size, alignment);
204 base = os::reserve_memory_aligned(size, alignment);
205
206 if (requested_address != 0 &&
207 failed_to_reserve_as_requested(base, requested_address, size, false)) {
208 // As a result of the alignment constraints, the allocated base differs
209 // from the requested address. Return back to the caller who can
210 // take remedial action (like try again without a requested address).
211 assert(_base == NULL, "should be");
212 return;
213 }
214 }
215 }
216 // Done
217 _base = base;
218 _size = size;
219 _alignment = alignment;
220 _noaccess_prefix = noaccess_prefix;
221
222 // Assert that if noaccess_prefix is used, it is the same as alignment.
223 assert(noaccess_prefix == 0 ||
224 noaccess_prefix == _alignment, "noaccess prefix wrong");
225
226 assert(markOopDesc::encode_pointer_as_mark(_base)->decode_pointer() == _base,
227 "area must be distinguishable from marks for mark-sweep");
228 assert(markOopDesc::encode_pointer_as_mark(&_base[size])->decode_pointer() == &_base[size],
229 "area must be distinguishable from marks for mark-sweep");
230 }
231
232
233 ReservedSpace::ReservedSpace(char* base, size_t size, size_t alignment,
234 bool special, bool executable) {
235 assert((size % os::vm_allocation_granularity()) == 0,
236 "size not allocation aligned");
237 _base = base;
238 _size = size;
239 _alignment = alignment;
240 _noaccess_prefix = 0;
241 _special = special;
242 _executable = executable;
243 }
244
245
246 ReservedSpace ReservedSpace::first_part(size_t partition_size, size_t alignment,
247 bool split, bool realloc) {
248 assert(partition_size <= size(), "partition failed");
249 if (split) {
250 os::split_reserved_memory(base(), size(), partition_size, realloc);
251 }
252 ReservedSpace result(base(), partition_size, alignment, special(),
253 executable());
254 return result;
255 }
256
257
258 ReservedSpace
259 ReservedSpace::last_part(size_t partition_size, size_t alignment) {
260 assert(partition_size <= size(), "partition failed");
261 ReservedSpace result(base() + partition_size, size() - partition_size,
262 alignment, special(), executable());
263 return result;
264 }
265
266
267 size_t ReservedSpace::page_align_size_up(size_t size) {
268 return align_size_up(size, os::vm_page_size());
269 }
270
271
272 size_t ReservedSpace::page_align_size_down(size_t size) {
273 return align_size_down(size, os::vm_page_size());
274 }
275
276
277 size_t ReservedSpace::allocation_align_size_up(size_t size) {
278 return align_size_up(size, os::vm_allocation_granularity());
279 }
280
281
282 size_t ReservedSpace::allocation_align_size_down(size_t size) {
283 return align_size_down(size, os::vm_allocation_granularity());
284 }
285
286
287 void ReservedSpace::release() {
288 if (is_reserved()) {
289 char *real_base = _base - _noaccess_prefix;
290 const size_t real_size = _size + _noaccess_prefix;
291 if (special()) {
292 os::release_memory_special(real_base, real_size);
293 } else{
294 os::release_memory(real_base, real_size);
295 }
296 _base = NULL;
297 _size = 0;
298 _noaccess_prefix = 0;
299 _special = false;
300 _executable = false;
301 }
302 }
303
304 void ReservedSpace::protect_noaccess_prefix(const size_t size) {
305
306 // If there is no noaccess prefix, return.
307 if (_noaccess_prefix == 0) return;
308
309 assert(_noaccess_prefix >= (size_t)os::vm_page_size(),
310 "must be at least page size big");
311
312 if (true
313 WIN64_ONLY(&& !UseLargePages)
314 AIX_ONLY(&& os::vm_page_size() != SIZE_64K)) {
315 // Protect memory at the base of the allocated region.
316 // If special, the page was committed (only matters on windows)
317 if (!os::protect_memory(_base, _noaccess_prefix, os::MEM_PROT_NONE,
318 _special)) {
319 fatal("cannot protect protection page");
320 }
321 if (PrintCompressedOopsMode) {
322 tty->cr();
323 tty->print_cr("Protected page at the reserved heap base: " PTR_FORMAT " / " INTX_FORMAT " bytes", _base, _noaccess_prefix);
324 }
325 assert(Universe::narrow_oop_use_implicit_null_checks() == true, "not initialized?");
326 } else {
327 Universe::set_narrow_oop_use_implicit_null_checks(false);
328 }
329
330 _base += _noaccess_prefix;
331 _size -= _noaccess_prefix;
332 assert((size == _size) && ((uintptr_t)_base % _alignment == 0),
333 "must be exactly of required size and alignment");
334 }
335
336 ReservedHeapSpace::ReservedHeapSpace(size_t size, size_t alignment,
337 bool large, char* requested_address) :
338 ReservedSpace(size, alignment, large,
339 requested_address,
340 (UseCompressedOops && (requested_address == NULL || requested_address+size > (char*)OopEncodingHeapMax) ?
341 noaccess_prefix_size(alignment) : 0)) {
342
343 if (base() > 0) {
344 MemTracker::record_virtual_memory_type((address)base(), mtJavaHeap);
345 }
346
347 // Only reserved space for the java heap should have a noaccess_prefix
348 // if using compressed oops.
349 protect_noaccess_prefix(size);
350 }
351
352 size_t ReservedHeapSpace::noaccess_prefix_size(size_t alignment) {
353 return lcm(os::vm_page_size(), alignment);
354 }
355 // Reserve space for code segment. Same as Java heap only we mark this as
356 // executable.
357 ReservedCodeSpace::ReservedCodeSpace(size_t r_size,
358 size_t rs_align,
359 bool large) :
360 ReservedSpace(r_size, rs_align, large, /*executable*/ true) {
361 MemTracker::record_virtual_memory_type((address)base(), mtCode);
362 }
363
364 // VirtualSpace
365
366 VirtualSpace::VirtualSpace() {
367 _low_boundary = NULL;
368 _high_boundary = NULL;
369 _low = NULL;
370 _high = NULL;
371 _lower_high = NULL;
372 _middle_high = NULL;
373 _upper_high = NULL;
374 _lower_high_boundary = NULL;
375 _middle_high_boundary = NULL;
376 _upper_high_boundary = NULL;
377 _lower_alignment = 0;
378 _middle_alignment = 0;
379 _upper_alignment = 0;
380 _special = false;
381 _executable = false;
382 }
383
384
385 bool VirtualSpace::initialize(ReservedSpace rs, size_t committed_size) {
386 const size_t max_commit_granularity = os::page_size_for_region(rs.size(), 1);
387 return initialize_with_granularity(rs, committed_size, max_commit_granularity);
388 }
389
390 bool VirtualSpace::initialize_with_granularity(ReservedSpace rs, size_t committed_size, size_t max_commit_granularity) {
391 if(!rs.is_reserved()) return false; // allocation failed.
392 assert(_low_boundary == NULL, "VirtualSpace already initialized");
393 assert(max_commit_granularity > 0, "Granularity must be non-zero.");
394
395 _low_boundary = rs.base();
396 _high_boundary = low_boundary() + rs.size();
397
398 _low = low_boundary();
399 _high = low();
400
401 _special = rs.special();
402 _executable = rs.executable();
403
404 // When a VirtualSpace begins life at a large size, make all future expansion
405 // and shrinking occur aligned to a granularity of large pages. This avoids
406 // fragmentation of physical addresses that inhibits the use of large pages
407 // by the OS virtual memory system. Empirically, we see that with a 4MB
408 // page size, the only spaces that get handled this way are codecache and
409 // the heap itself, both of which provide a substantial performance
410 // boost in many benchmarks when covered by large pages.
411 //
412 // No attempt is made to force large page alignment at the very top and
413 // bottom of the space if they are not aligned so already.
414 _lower_alignment = os::vm_page_size();
415 _middle_alignment = max_commit_granularity;
416 _upper_alignment = os::vm_page_size();
417
418 // End of each region
419 _lower_high_boundary = (char*) round_to((intptr_t) low_boundary(), middle_alignment());
420 _middle_high_boundary = (char*) round_down((intptr_t) high_boundary(), middle_alignment());
421 _upper_high_boundary = high_boundary();
422
423 // High address of each region
424 _lower_high = low_boundary();
425 _middle_high = lower_high_boundary();
426 _upper_high = middle_high_boundary();
427
428 // commit to initial size
429 if (committed_size > 0) {
430 if (!expand_by(committed_size)) {
431 return false;
432 }
433 }
434 return true;
435 }
436
437
438 VirtualSpace::~VirtualSpace() {
439 release();
440 }
441
442
443 void VirtualSpace::release() {
444 // This does not release memory it never reserved.
445 // Caller must release via rs.release();
446 _low_boundary = NULL;
447 _high_boundary = NULL;
448 _low = NULL;
449 _high = NULL;
450 _lower_high = NULL;
451 _middle_high = NULL;
452 _upper_high = NULL;
453 _lower_high_boundary = NULL;
454 _middle_high_boundary = NULL;
455 _upper_high_boundary = NULL;
456 _lower_alignment = 0;
457 _middle_alignment = 0;
458 _upper_alignment = 0;
459 _special = false;
460 _executable = false;
461 }
462
463
464 size_t VirtualSpace::committed_size() const {
465 return pointer_delta(high(), low(), sizeof(char));
466 }
467
468
469 size_t VirtualSpace::reserved_size() const {
470 return pointer_delta(high_boundary(), low_boundary(), sizeof(char));
471 }
472
473
474 size_t VirtualSpace::uncommitted_size() const {
475 return reserved_size() - committed_size();
476 }
477
478 size_t VirtualSpace::actual_committed_size() const {
479 // Special VirtualSpaces commit all reserved space up front.
480 if (special()) {
481 return reserved_size();
482 }
483
484 size_t committed_low = pointer_delta(_lower_high, _low_boundary, sizeof(char));
485 size_t committed_middle = pointer_delta(_middle_high, _lower_high_boundary, sizeof(char));
486 size_t committed_high = pointer_delta(_upper_high, _middle_high_boundary, sizeof(char));
487
488 #ifdef ASSERT
489 size_t lower = pointer_delta(_lower_high_boundary, _low_boundary, sizeof(char));
490 size_t middle = pointer_delta(_middle_high_boundary, _lower_high_boundary, sizeof(char));
491 size_t upper = pointer_delta(_upper_high_boundary, _middle_high_boundary, sizeof(char));
492
493 if (committed_high > 0) {
494 assert(committed_low == lower, "Must be");
495 assert(committed_middle == middle, "Must be");
496 }
497
498 if (committed_middle > 0) {
499 assert(committed_low == lower, "Must be");
500 }
501 if (committed_middle < middle) {
502 assert(committed_high == 0, "Must be");
503 }
504
505 if (committed_low < lower) {
506 assert(committed_high == 0, "Must be");
507 assert(committed_middle == 0, "Must be");
508 }
509 #endif
510
511 return committed_low + committed_middle + committed_high;
512 }
513
514
515 bool VirtualSpace::contains(const void* p) const {
516 return low() <= (const char*) p && (const char*) p < high();
517 }
518
519 /*
520 First we need to determine if a particular virtual space is using large
521 pages. This is done at the initialize function and only virtual spaces
522 that are larger than LargePageSizeInBytes use large pages. Once we
523 have determined this, all expand_by and shrink_by calls must grow and
524 shrink by large page size chunks. If a particular request
525 is within the current large page, the call to commit and uncommit memory
526 can be ignored. In the case that the low and high boundaries of this
527 space is not large page aligned, the pages leading to the first large
528 page address and the pages after the last large page address must be
529 allocated with default pages.
530 */
531 bool VirtualSpace::expand_by(size_t bytes, bool pre_touch) {
532 if (uncommitted_size() < bytes) return false;
533
534 if (special()) {
535 // don't commit memory if the entire space is pinned in memory
536 _high += bytes;
537 return true;
538 }
539
540 char* previous_high = high();
541 char* unaligned_new_high = high() + bytes;
542 assert(unaligned_new_high <= high_boundary(),
543 "cannot expand by more than upper boundary");
544
545 // Calculate where the new high for each of the regions should be. If
546 // the low_boundary() and high_boundary() are LargePageSizeInBytes aligned
547 // then the unaligned lower and upper new highs would be the
548 // lower_high() and upper_high() respectively.
549 char* unaligned_lower_new_high =
550 MIN2(unaligned_new_high, lower_high_boundary());
551 char* unaligned_middle_new_high =
552 MIN2(unaligned_new_high, middle_high_boundary());
553 char* unaligned_upper_new_high =
554 MIN2(unaligned_new_high, upper_high_boundary());
555
556 // Align the new highs based on the regions alignment. lower and upper
557 // alignment will always be default page size. middle alignment will be
558 // LargePageSizeInBytes if the actual size of the virtual space is in
559 // fact larger than LargePageSizeInBytes.
560 char* aligned_lower_new_high =
561 (char*) round_to((intptr_t) unaligned_lower_new_high, lower_alignment());
562 char* aligned_middle_new_high =
563 (char*) round_to((intptr_t) unaligned_middle_new_high, middle_alignment());
564 char* aligned_upper_new_high =
565 (char*) round_to((intptr_t) unaligned_upper_new_high, upper_alignment());
566
567 // Determine which regions need to grow in this expand_by call.
568 // If you are growing in the lower region, high() must be in that
569 // region so calculate the size based on high(). For the middle and
570 // upper regions, determine the starting point of growth based on the
571 // location of high(). By getting the MAX of the region's low address
572 // (or the previous region's high address) and high(), we can tell if it
573 // is an intra or inter region growth.
574 size_t lower_needs = 0;
575 if (aligned_lower_new_high > lower_high()) {
576 lower_needs =
577 pointer_delta(aligned_lower_new_high, lower_high(), sizeof(char));
578 }
579 size_t middle_needs = 0;
580 if (aligned_middle_new_high > middle_high()) {
581 middle_needs =
582 pointer_delta(aligned_middle_new_high, middle_high(), sizeof(char));
583 }
584 size_t upper_needs = 0;
585 if (aligned_upper_new_high > upper_high()) {
586 upper_needs =
587 pointer_delta(aligned_upper_new_high, upper_high(), sizeof(char));
588 }
589
590 // Check contiguity.
591 assert(low_boundary() <= lower_high() &&
592 lower_high() <= lower_high_boundary(),
593 "high address must be contained within the region");
594 assert(lower_high_boundary() <= middle_high() &&
595 middle_high() <= middle_high_boundary(),
596 "high address must be contained within the region");
597 assert(middle_high_boundary() <= upper_high() &&
598 upper_high() <= upper_high_boundary(),
599 "high address must be contained within the region");
600
601 // Commit regions
602 if (lower_needs > 0) {
603 assert(low_boundary() <= lower_high() &&
604 lower_high() + lower_needs <= lower_high_boundary(),
605 "must not expand beyond region");
606 if (!os::commit_memory(lower_high(), lower_needs, _executable)) {
607 debug_only(warning("INFO: os::commit_memory(" PTR_FORMAT
608 ", lower_needs=" SIZE_FORMAT ", %d) failed",
609 lower_high(), lower_needs, _executable);)
610 return false;
611 } else {
612 _lower_high += lower_needs;
613 }
614 }
615 if (middle_needs > 0) {
616 assert(lower_high_boundary() <= middle_high() &&
617 middle_high() + middle_needs <= middle_high_boundary(),
618 "must not expand beyond region");
619 if (!os::commit_memory(middle_high(), middle_needs, middle_alignment(),
620 _executable)) {
621 debug_only(warning("INFO: os::commit_memory(" PTR_FORMAT
622 ", middle_needs=" SIZE_FORMAT ", " SIZE_FORMAT
623 ", %d) failed", middle_high(), middle_needs,
624 middle_alignment(), _executable);)
625 return false;
626 }
627 _middle_high += middle_needs;
628 }
629 if (upper_needs > 0) {
630 assert(middle_high_boundary() <= upper_high() &&
631 upper_high() + upper_needs <= upper_high_boundary(),
632 "must not expand beyond region");
633 if (!os::commit_memory(upper_high(), upper_needs, _executable)) {
634 debug_only(warning("INFO: os::commit_memory(" PTR_FORMAT
635 ", upper_needs=" SIZE_FORMAT ", %d) failed",
636 upper_high(), upper_needs, _executable);)
637 return false;
638 } else {
639 _upper_high += upper_needs;
640 }
641 }
642
643 if (pre_touch || AlwaysPreTouch) {
644 int vm_ps = os::vm_page_size();
645 for (char* curr = previous_high;
646 curr < unaligned_new_high;
647 curr += vm_ps) {
648 // Note the use of a write here; originally we tried just a read, but
649 // since the value read was unused, the optimizer removed the read.
650 // If we ever have a concurrent touchahead thread, we'll want to use
651 // a read, to avoid the potential of overwriting data (if a mutator
652 // thread beats the touchahead thread to a page). There are various
653 // ways of making sure this read is not optimized away: for example,
654 // generating the code for a read procedure at runtime.
655 *curr = 0;
656 }
657 }
658
659 _high += bytes;
660 return true;
661 }
662
663 // A page is uncommitted if the contents of the entire page is deemed unusable.
664 // Continue to decrement the high() pointer until it reaches a page boundary
665 // in which case that particular page can now be uncommitted.
666 void VirtualSpace::shrink_by(size_t size) {
667 if (committed_size() < size)
668 fatal("Cannot shrink virtual space to negative size");
669
670 if (special()) {
671 // don't uncommit if the entire space is pinned in memory
672 _high -= size;
673 return;
674 }
675
676 char* unaligned_new_high = high() - size;
677 assert(unaligned_new_high >= low_boundary(), "cannot shrink past lower boundary");
678
679 // Calculate new unaligned address
680 char* unaligned_upper_new_high =
681 MAX2(unaligned_new_high, middle_high_boundary());
682 char* unaligned_middle_new_high =
683 MAX2(unaligned_new_high, lower_high_boundary());
684 char* unaligned_lower_new_high =
685 MAX2(unaligned_new_high, low_boundary());
686
687 // Align address to region's alignment
688 char* aligned_upper_new_high =
689 (char*) round_to((intptr_t) unaligned_upper_new_high, upper_alignment());
690 char* aligned_middle_new_high =
691 (char*) round_to((intptr_t) unaligned_middle_new_high, middle_alignment());
692 char* aligned_lower_new_high =
693 (char*) round_to((intptr_t) unaligned_lower_new_high, lower_alignment());
694
695 // Determine which regions need to shrink
696 size_t upper_needs = 0;
697 if (aligned_upper_new_high < upper_high()) {
698 upper_needs =
699 pointer_delta(upper_high(), aligned_upper_new_high, sizeof(char));
700 }
701 size_t middle_needs = 0;
702 if (aligned_middle_new_high < middle_high()) {
703 middle_needs =
704 pointer_delta(middle_high(), aligned_middle_new_high, sizeof(char));
705 }
706 size_t lower_needs = 0;
707 if (aligned_lower_new_high < lower_high()) {
708 lower_needs =
709 pointer_delta(lower_high(), aligned_lower_new_high, sizeof(char));
710 }
711
712 // Check contiguity.
713 assert(middle_high_boundary() <= upper_high() &&
714 upper_high() <= upper_high_boundary(),
715 "high address must be contained within the region");
716 assert(lower_high_boundary() <= middle_high() &&
717 middle_high() <= middle_high_boundary(),
718 "high address must be contained within the region");
719 assert(low_boundary() <= lower_high() &&
720 lower_high() <= lower_high_boundary(),
721 "high address must be contained within the region");
722
723 // Uncommit
724 if (upper_needs > 0) {
725 assert(middle_high_boundary() <= aligned_upper_new_high &&
726 aligned_upper_new_high + upper_needs <= upper_high_boundary(),
727 "must not shrink beyond region");
728 if (!os::uncommit_memory(aligned_upper_new_high, upper_needs)) {
729 debug_only(warning("os::uncommit_memory failed"));
730 return;
731 } else {
732 _upper_high -= upper_needs;
733 }
734 }
735 if (middle_needs > 0) {
736 assert(lower_high_boundary() <= aligned_middle_new_high &&
737 aligned_middle_new_high + middle_needs <= middle_high_boundary(),
738 "must not shrink beyond region");
739 if (!os::uncommit_memory(aligned_middle_new_high, middle_needs)) {
740 debug_only(warning("os::uncommit_memory failed"));
741 return;
742 } else {
743 _middle_high -= middle_needs;
744 }
745 }
746 if (lower_needs > 0) {
747 assert(low_boundary() <= aligned_lower_new_high &&
748 aligned_lower_new_high + lower_needs <= lower_high_boundary(),
749 "must not shrink beyond region");
750 if (!os::uncommit_memory(aligned_lower_new_high, lower_needs)) {
751 debug_only(warning("os::uncommit_memory failed"));
752 return;
753 } else {
754 _lower_high -= lower_needs;
755 }
756 }
757
758 _high -= size;
759 }
760
761 #ifndef PRODUCT
762 void VirtualSpace::check_for_contiguity() {
763 // Check contiguity.
764 assert(low_boundary() <= lower_high() &&
765 lower_high() <= lower_high_boundary(),
766 "high address must be contained within the region");
767 assert(lower_high_boundary() <= middle_high() &&
768 middle_high() <= middle_high_boundary(),
769 "high address must be contained within the region");
770 assert(middle_high_boundary() <= upper_high() &&
771 upper_high() <= upper_high_boundary(),
772 "high address must be contained within the region");
773 assert(low() >= low_boundary(), "low");
774 assert(low_boundary() <= lower_high_boundary(), "lower high boundary");
775 assert(upper_high_boundary() <= high_boundary(), "upper high boundary");
776 assert(high() <= upper_high(), "upper high");
777 }
778
779 void VirtualSpace::print_on(outputStream* out) {
780 out->print ("Virtual space:");
781 if (special()) out->print(" (pinned in memory)");
782 out->cr();
783 out->print_cr(" - committed: " SIZE_FORMAT, committed_size());
784 out->print_cr(" - reserved: " SIZE_FORMAT, reserved_size());
785 out->print_cr(" - [low, high]: [" INTPTR_FORMAT ", " INTPTR_FORMAT "]", low(), high());
786 out->print_cr(" - [low_b, high_b]: [" INTPTR_FORMAT ", " INTPTR_FORMAT "]", low_boundary(), high_boundary());
787 }
788
789 void VirtualSpace::print() {
790 print_on(tty);
791 }
792
793 /////////////// Unit tests ///////////////
794
795 #ifndef PRODUCT
796
797 #define test_log(...) \
798 do {\
799 if (VerboseInternalVMTests) { \
800 tty->print_cr(__VA_ARGS__); \
801 tty->flush(); \
802 }\
803 } while (false)
804
805 class TestReservedSpace : AllStatic {
806 public:
807 static void small_page_write(void* addr, size_t size) {
808 size_t page_size = os::vm_page_size();
809
810 char* end = (char*)addr + size;
811 for (char* p = (char*)addr; p < end; p += page_size) {
812 *p = 1;
813 }
814 }
815
816 static void release_memory_for_test(ReservedSpace rs) {
817 if (rs.special()) {
818 guarantee(os::release_memory_special(rs.base(), rs.size()), "Shouldn't fail");
819 } else {
820 guarantee(os::release_memory(rs.base(), rs.size()), "Shouldn't fail");
821 }
822 }
823
824 static void test_reserved_space1(size_t size, size_t alignment) {
825 test_log("test_reserved_space1(%p)", (void*) (uintptr_t) size);
826
827 assert(is_size_aligned(size, alignment), "Incorrect input parameters");
828
829 ReservedSpace rs(size, // size
830 alignment, // alignment
831 UseLargePages, // large
832 NULL, // requested_address
833 0); // noacces_prefix
834
835 test_log(" rs.special() == %d", rs.special());
836
837 assert(rs.base() != NULL, "Must be");
838 assert(rs.size() == size, "Must be");
839
840 assert(is_ptr_aligned(rs.base(), alignment), "aligned sizes should always give aligned addresses");
841 assert(is_size_aligned(rs.size(), alignment), "aligned sizes should always give aligned addresses");
842
843 if (rs.special()) {
844 small_page_write(rs.base(), size);
845 }
846
847 release_memory_for_test(rs);
848 }
849
850 static void test_reserved_space2(size_t size) {
851 test_log("test_reserved_space2(%p)", (void*)(uintptr_t)size);
852
853 assert(is_size_aligned(size, os::vm_allocation_granularity()), "Must be at least AG aligned");
854
855 ReservedSpace rs(size);
856
857 test_log(" rs.special() == %d", rs.special());
858
859 assert(rs.base() != NULL, "Must be");
860 assert(rs.size() == size, "Must be");
861
862 if (rs.special()) {
863 small_page_write(rs.base(), size);
864 }
865
866 release_memory_for_test(rs);
867 }
868
869 static void test_reserved_space3(size_t size, size_t alignment, bool maybe_large) {
870 test_log("test_reserved_space3(%p, %p, %d)",
871 (void*)(uintptr_t)size, (void*)(uintptr_t)alignment, maybe_large);
872
873 assert(is_size_aligned(size, os::vm_allocation_granularity()), "Must be at least AG aligned");
874 assert(is_size_aligned(size, alignment), "Must be at least aligned against alignment");
875
876 bool large = maybe_large && UseLargePages && size >= os::large_page_size();
877
878 ReservedSpace rs(size, alignment, large, false);
879
880 test_log(" rs.special() == %d", rs.special());
881
882 assert(rs.base() != NULL, "Must be");
883 assert(rs.size() == size, "Must be");
884
885 if (rs.special()) {
886 small_page_write(rs.base(), size);
887 }
888
889 release_memory_for_test(rs);
890 }
891
892
893 static void test_reserved_space1() {
894 size_t size = 2 * 1024 * 1024;
895 size_t ag = os::vm_allocation_granularity();
896
897 test_reserved_space1(size, ag);
898 test_reserved_space1(size * 2, ag);
899 test_reserved_space1(size * 10, ag);
900 }
901
902 static void test_reserved_space2() {
903 size_t size = 2 * 1024 * 1024;
904 size_t ag = os::vm_allocation_granularity();
905
906 test_reserved_space2(size * 1);
907 test_reserved_space2(size * 2);
908 test_reserved_space2(size * 10);
909 test_reserved_space2(ag);
910 test_reserved_space2(size - ag);
911 test_reserved_space2(size);
912 test_reserved_space2(size + ag);
913 test_reserved_space2(size * 2);
914 test_reserved_space2(size * 2 - ag);
915 test_reserved_space2(size * 2 + ag);
916 test_reserved_space2(size * 3);
917 test_reserved_space2(size * 3 - ag);
918 test_reserved_space2(size * 3 + ag);
919 test_reserved_space2(size * 10);
920 test_reserved_space2(size * 10 + size / 2);
921 }
922
923 static void test_reserved_space3() {
924 size_t ag = os::vm_allocation_granularity();
925
926 test_reserved_space3(ag, ag , false);
927 test_reserved_space3(ag * 2, ag , false);
928 test_reserved_space3(ag * 3, ag , false);
929 test_reserved_space3(ag * 2, ag * 2, false);
930 test_reserved_space3(ag * 4, ag * 2, false);
931 test_reserved_space3(ag * 8, ag * 2, false);
932 test_reserved_space3(ag * 4, ag * 4, false);
933 test_reserved_space3(ag * 8, ag * 4, false);
934 test_reserved_space3(ag * 16, ag * 4, false);
935
936 if (UseLargePages) {
937 size_t lp = os::large_page_size();
938
939 // Without large pages
940 test_reserved_space3(lp, ag * 4, false);
941 test_reserved_space3(lp * 2, ag * 4, false);
942 test_reserved_space3(lp * 4, ag * 4, false);
943 test_reserved_space3(lp, lp , false);
944 test_reserved_space3(lp * 2, lp , false);
945 test_reserved_space3(lp * 3, lp , false);
946 test_reserved_space3(lp * 2, lp * 2, false);
947 test_reserved_space3(lp * 4, lp * 2, false);
948 test_reserved_space3(lp * 8, lp * 2, false);
949
950 // With large pages
951 test_reserved_space3(lp, ag * 4 , true);
952 test_reserved_space3(lp * 2, ag * 4, true);
953 test_reserved_space3(lp * 4, ag * 4, true);
954 test_reserved_space3(lp, lp , true);
955 test_reserved_space3(lp * 2, lp , true);
956 test_reserved_space3(lp * 3, lp , true);
957 test_reserved_space3(lp * 2, lp * 2, true);
958 test_reserved_space3(lp * 4, lp * 2, true);
959 test_reserved_space3(lp * 8, lp * 2, true);
960 }
961 }
962
963 static void test_reserved_space() {
964 test_reserved_space1();
965 test_reserved_space2();
966 test_reserved_space3();
967 }
968 };
969
970 void TestReservedSpace_test() {
971 TestReservedSpace::test_reserved_space();
972 }
973
974 #define assert_equals(actual, expected) \
975 assert(actual == expected, \
976 err_msg("Got " SIZE_FORMAT " expected " \
977 SIZE_FORMAT, actual, expected));
978
979 #define assert_ge(value1, value2) \
980 assert(value1 >= value2, \
981 err_msg("'" #value1 "': " SIZE_FORMAT " '" \
982 #value2 "': " SIZE_FORMAT, value1, value2));
983
984 #define assert_lt(value1, value2) \
985 assert(value1 < value2, \
986 err_msg("'" #value1 "': " SIZE_FORMAT " '" \
987 #value2 "': " SIZE_FORMAT, value1, value2));
988
989
990 class TestVirtualSpace : AllStatic {
991 enum TestLargePages {
992 Default,
993 Disable,
994 Reserve,
995 Commit
996 };
997
998 static ReservedSpace reserve_memory(size_t reserve_size_aligned, TestLargePages mode) {
999 switch(mode) {
1000 default:
1001 case Default:
1002 case Reserve:
1003 return ReservedSpace(reserve_size_aligned);
1004 case Disable:
1005 case Commit:
1006 return ReservedSpace(reserve_size_aligned,
1007 os::vm_allocation_granularity(),
1008 /* large */ false, /* exec */ false);
1009 }
1010 }
1011
1012 static bool initialize_virtual_space(VirtualSpace& vs, ReservedSpace rs, TestLargePages mode) {
1013 switch(mode) {
1014 default:
1015 case Default:
1016 case Reserve:
1017 return vs.initialize(rs, 0);
1018 case Disable:
1019 return vs.initialize_with_granularity(rs, 0, os::vm_page_size());
1020 case Commit:
1021 return vs.initialize_with_granularity(rs, 0, os::page_size_for_region(rs.size(), 1));
1022 }
1023 }
1024
1025 public:
1026 static void test_virtual_space_actual_committed_space(size_t reserve_size, size_t commit_size,
1027 TestLargePages mode = Default) {
1028 size_t granularity = os::vm_allocation_granularity();
1029 size_t reserve_size_aligned = align_size_up(reserve_size, granularity);
1030
1031 ReservedSpace reserved = reserve_memory(reserve_size_aligned, mode);
1032
1033 assert(reserved.is_reserved(), "Must be");
1034
1035 VirtualSpace vs;
1036 bool initialized = initialize_virtual_space(vs, reserved, mode);
1037 assert(initialized, "Failed to initialize VirtualSpace");
1038
1039 vs.expand_by(commit_size, false);
1040
1041 if (vs.special()) {
1042 assert_equals(vs.actual_committed_size(), reserve_size_aligned);
1043 } else {
1044 assert_ge(vs.actual_committed_size(), commit_size);
1045 // Approximate the commit granularity.
1046 // Make sure that we don't commit using large pages
1047 // if large pages has been disabled for this VirtualSpace.
1048 size_t commit_granularity = (mode == Disable || !UseLargePages) ?
1049 os::vm_page_size() : os::large_page_size();
1050 assert_lt(vs.actual_committed_size(), commit_size + commit_granularity);
1051 }
1052
1053 reserved.release();
1054 }
1055
1056 static void test_virtual_space_actual_committed_space_one_large_page() {
1057 if (!UseLargePages) {
1058 return;
1059 }
1060
1061 size_t large_page_size = os::large_page_size();
1062
1063 ReservedSpace reserved(large_page_size, large_page_size, true, false);
1064
1065 assert(reserved.is_reserved(), "Must be");
1066
1067 VirtualSpace vs;
1068 bool initialized = vs.initialize(reserved, 0);
1069 assert(initialized, "Failed to initialize VirtualSpace");
1070
1071 vs.expand_by(large_page_size, false);
1072
1073 assert_equals(vs.actual_committed_size(), large_page_size);
1074
1075 reserved.release();
1076 }
1077
1078 static void test_virtual_space_actual_committed_space() {
1079 test_virtual_space_actual_committed_space(4 * K, 0);
1080 test_virtual_space_actual_committed_space(4 * K, 4 * K);
1081 test_virtual_space_actual_committed_space(8 * K, 0);
1082 test_virtual_space_actual_committed_space(8 * K, 4 * K);
1083 test_virtual_space_actual_committed_space(8 * K, 8 * K);
1084 test_virtual_space_actual_committed_space(12 * K, 0);
1085 test_virtual_space_actual_committed_space(12 * K, 4 * K);
1086 test_virtual_space_actual_committed_space(12 * K, 8 * K);
1087 test_virtual_space_actual_committed_space(12 * K, 12 * K);
1088 test_virtual_space_actual_committed_space(64 * K, 0);
1089 test_virtual_space_actual_committed_space(64 * K, 32 * K);
1090 test_virtual_space_actual_committed_space(64 * K, 64 * K);
1091 test_virtual_space_actual_committed_space(2 * M, 0);
1092 test_virtual_space_actual_committed_space(2 * M, 4 * K);
1093 test_virtual_space_actual_committed_space(2 * M, 64 * K);
1094 test_virtual_space_actual_committed_space(2 * M, 1 * M);
1095 test_virtual_space_actual_committed_space(2 * M, 2 * M);
1096 test_virtual_space_actual_committed_space(10 * M, 0);
1097 test_virtual_space_actual_committed_space(10 * M, 4 * K);
1098 test_virtual_space_actual_committed_space(10 * M, 8 * K);
1099 test_virtual_space_actual_committed_space(10 * M, 1 * M);
1100 test_virtual_space_actual_committed_space(10 * M, 2 * M);
1101 test_virtual_space_actual_committed_space(10 * M, 5 * M);
1102 test_virtual_space_actual_committed_space(10 * M, 10 * M);
1103 }
1104
1105 static void test_virtual_space_disable_large_pages() {
1106 if (!UseLargePages) {
1107 return;
1108 }
1109 // These test cases verify that if we force VirtualSpace to disable large pages
1110 test_virtual_space_actual_committed_space(10 * M, 0, Disable);
1111 test_virtual_space_actual_committed_space(10 * M, 4 * K, Disable);
1112 test_virtual_space_actual_committed_space(10 * M, 8 * K, Disable);
1113 test_virtual_space_actual_committed_space(10 * M, 1 * M, Disable);
1114 test_virtual_space_actual_committed_space(10 * M, 2 * M, Disable);
1115 test_virtual_space_actual_committed_space(10 * M, 5 * M, Disable);
1116 test_virtual_space_actual_committed_space(10 * M, 10 * M, Disable);
1117
1118 test_virtual_space_actual_committed_space(10 * M, 0, Reserve);
1119 test_virtual_space_actual_committed_space(10 * M, 4 * K, Reserve);
1120 test_virtual_space_actual_committed_space(10 * M, 8 * K, Reserve);
1121 test_virtual_space_actual_committed_space(10 * M, 1 * M, Reserve);
1122 test_virtual_space_actual_committed_space(10 * M, 2 * M, Reserve);
1123 test_virtual_space_actual_committed_space(10 * M, 5 * M, Reserve);
1124 test_virtual_space_actual_committed_space(10 * M, 10 * M, Reserve);
1125
1126 test_virtual_space_actual_committed_space(10 * M, 0, Commit);
1127 test_virtual_space_actual_committed_space(10 * M, 4 * K, Commit);
1128 test_virtual_space_actual_committed_space(10 * M, 8 * K, Commit);
1129 test_virtual_space_actual_committed_space(10 * M, 1 * M, Commit);
1130 test_virtual_space_actual_committed_space(10 * M, 2 * M, Commit);
1131 test_virtual_space_actual_committed_space(10 * M, 5 * M, Commit);
1132 test_virtual_space_actual_committed_space(10 * M, 10 * M, Commit);
1133 }
1134
1135 static void test_virtual_space() {
1136 test_virtual_space_actual_committed_space();
1137 test_virtual_space_actual_committed_space_one_large_page();
1138 test_virtual_space_disable_large_pages();
1139 }
1140 };
1141
1142 void TestVirtualSpace_test() {
1143 TestVirtualSpace::test_virtual_space();
1144 }
1145
1146 #endif // PRODUCT
1147
1148 #endif