1 /*
2 * Copyright (c) 1997, 2024, 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.
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23 */
24
25 #include "precompiled.hpp"
26 #include "logging/log.hpp"
27 #include "memory/resourceArea.hpp"
28 #include "memory/virtualspace.hpp"
29 #include "nmt/memTracker.hpp"
30 #include "oops/compressedKlass.hpp"
31 #include "oops/compressedOops.hpp"
32 #include "oops/markWord.hpp"
33 #include "oops/oop.inline.hpp"
34 #include "runtime/globals_extension.hpp"
35 #include "runtime/java.hpp"
36 #include "runtime/os.hpp"
37 #include "utilities/align.hpp"
38 #include "utilities/formatBuffer.hpp"
39 #include "utilities/powerOfTwo.hpp"
40
41 // ReservedSpace
42
43 // Dummy constructor
44 ReservedSpace::ReservedSpace() : _base(nullptr), _size(0), _noaccess_prefix(0),
45 _alignment(0), _special(false), _fd_for_heap(-1), _executable(false) {
46 }
47
48 ReservedSpace::ReservedSpace(size_t size) : _fd_for_heap(-1) {
49 // Want to use large pages where possible. If the size is
50 // not large page aligned the mapping will be a mix of
51 // large and normal pages.
52 size_t page_size = os::page_size_for_region_unaligned(size, 1);
53 size_t alignment = os::vm_allocation_granularity();
54 initialize(size, alignment, page_size, nullptr, false);
55 }
56
57 ReservedSpace::ReservedSpace(size_t size, size_t preferred_page_size) : _fd_for_heap(-1) {
58 // When a page size is given we don't want to mix large
59 // and normal pages. If the size is not a multiple of the
60 // page size it will be aligned up to achieve this.
61 size_t alignment = os::vm_allocation_granularity();;
62 if (preferred_page_size != os::vm_page_size()) {
63 alignment = MAX2(preferred_page_size, alignment);
64 size = align_up(size, alignment);
65 }
66 initialize(size, alignment, preferred_page_size, nullptr, false);
67 }
68
69 ReservedSpace::ReservedSpace(size_t size,
70 size_t alignment,
71 size_t page_size,
72 char* requested_address) : _fd_for_heap(-1) {
73 initialize(size, alignment, page_size, requested_address, false);
74 }
75
76 ReservedSpace::ReservedSpace(char* base, size_t size, size_t alignment, size_t page_size,
77 bool special, bool executable) : _fd_for_heap(-1) {
78 assert((size % os::vm_allocation_granularity()) == 0,
79 "size not allocation aligned");
80 initialize_members(base, size, alignment, page_size, special, executable);
81 }
82
83 // Helper method
84 static char* attempt_map_or_reserve_memory_at(char* base, size_t size, int fd, bool executable) {
85 if (fd != -1) {
86 return os::attempt_map_memory_to_file_at(base, size, fd);
87 }
88 return os::attempt_reserve_memory_at(base, size, executable);
89 }
90
91 // Helper method
92 static char* map_or_reserve_memory(size_t size, int fd, bool executable) {
93 if (fd != -1) {
94 return os::map_memory_to_file(size, fd);
95 }
96 return os::reserve_memory(size, executable);
97 }
98
99 // Helper method
100 static char* map_or_reserve_memory_aligned(size_t size, size_t alignment, int fd, bool executable) {
101 if (fd != -1) {
102 return os::map_memory_to_file_aligned(size, alignment, fd);
103 }
104 return os::reserve_memory_aligned(size, alignment, executable);
105 }
106
107 // Helper method
108 static void unmap_or_release_memory(char* base, size_t size, bool is_file_mapped) {
109 if (is_file_mapped) {
110 if (!os::unmap_memory(base, size)) {
111 fatal("os::unmap_memory failed");
112 }
113 } else if (!os::release_memory(base, size)) {
114 fatal("os::release_memory failed");
115 }
116 }
117
118 // Helper method
119 static bool failed_to_reserve_as_requested(char* base, char* requested_address) {
120 if (base == requested_address || requested_address == nullptr) {
121 return false; // did not fail
122 }
123
124 if (base != nullptr) {
125 // Different reserve address may be acceptable in other cases
126 // but for compressed oops heap should be at requested address.
127 assert(UseCompressedOops, "currently requested address used only for compressed oops");
128 log_debug(gc, heap, coops)("Reserved memory not at requested address: " PTR_FORMAT " vs " PTR_FORMAT, p2i(base), p2i(requested_address));
129 }
130 return true;
131 }
132
133 static bool use_explicit_large_pages(size_t page_size) {
134 return !os::can_commit_large_page_memory() &&
135 page_size != os::vm_page_size();
136 }
137
138 static bool large_pages_requested() {
139 return UseLargePages &&
140 (!FLAG_IS_DEFAULT(UseLargePages) || !FLAG_IS_DEFAULT(LargePageSizeInBytes));
141 }
142
143 static void log_on_large_pages_failure(char* req_addr, size_t bytes) {
144 if (large_pages_requested()) {
145 // Compressed oops logging.
146 log_debug(gc, heap, coops)("Reserve regular memory without large pages");
147 // JVM style warning that we did not succeed in using large pages.
148 char msg[128];
149 jio_snprintf(msg, sizeof(msg), "Failed to reserve and commit memory using large pages. "
150 "req_addr: " PTR_FORMAT " bytes: " SIZE_FORMAT,
151 req_addr, bytes);
152 warning("%s", msg);
153 }
154 }
155
156 static char* reserve_memory(char* requested_address, const size_t size,
157 const size_t alignment, int fd, bool exec) {
158 char* base;
159 // If the memory was requested at a particular address, use
160 // os::attempt_reserve_memory_at() to avoid mapping over something
161 // important. If the reservation fails, return null.
162 if (requested_address != nullptr) {
163 assert(is_aligned(requested_address, alignment),
164 "Requested address " PTR_FORMAT " must be aligned to " SIZE_FORMAT,
165 p2i(requested_address), alignment);
166 base = attempt_map_or_reserve_memory_at(requested_address, size, fd, exec);
167 } else {
168 // Optimistically assume that the OS returns an aligned base pointer.
169 // When reserving a large address range, most OSes seem to align to at
170 // least 64K.
171 base = map_or_reserve_memory(size, fd, exec);
172 // Check alignment constraints. This is only needed when there is
173 // no requested address.
174 if (!is_aligned(base, alignment)) {
175 // Base not aligned, retry.
176 unmap_or_release_memory(base, size, fd != -1 /*is_file_mapped*/);
177 // Map using the requested alignment.
178 base = map_or_reserve_memory_aligned(size, alignment, fd, exec);
179 }
180 }
181
182 return base;
183 }
184
185 static char* reserve_memory_special(char* requested_address, const size_t size,
186 const size_t alignment, const size_t page_size, bool exec) {
187
188 log_trace(pagesize)("Attempt special mapping: size: " SIZE_FORMAT "%s, "
189 "alignment: " SIZE_FORMAT "%s",
190 byte_size_in_exact_unit(size), exact_unit_for_byte_size(size),
191 byte_size_in_exact_unit(alignment), exact_unit_for_byte_size(alignment));
192
193 char* base = os::reserve_memory_special(size, alignment, page_size, requested_address, exec);
194 if (base != nullptr) {
195 // Check alignment constraints.
196 assert(is_aligned(base, alignment),
197 "reserve_memory_special() returned an unaligned address, base: " PTR_FORMAT
198 " alignment: " SIZE_FORMAT_X,
199 p2i(base), alignment);
200 }
201 return base;
202 }
203
204 void ReservedSpace::clear_members() {
205 initialize_members(nullptr, 0, 0, 0, false, false);
206 }
207
208 void ReservedSpace::initialize_members(char* base, size_t size, size_t alignment,
209 size_t page_size, bool special, bool executable) {
210 _base = base;
211 _size = size;
212 _alignment = alignment;
213 _page_size = page_size;
214 _special = special;
215 _executable = executable;
216 _noaccess_prefix = 0;
217 }
218
219 void ReservedSpace::reserve(size_t size,
220 size_t alignment,
221 size_t page_size,
222 char* requested_address,
223 bool executable) {
224 assert(is_aligned(size, alignment), "Size must be aligned to the requested alignment");
225
226 // There are basically three different cases that we need to handle below:
227 // 1. Mapping backed by a file
228 // 2. Mapping backed by explicit large pages
229 // 3. Mapping backed by normal pages or transparent huge pages
230 // The first two have restrictions that requires the whole mapping to be
231 // committed up front. To record this the ReservedSpace is marked 'special'.
232
233 // == Case 1 ==
234 if (_fd_for_heap != -1) {
235 // When there is a backing file directory for this space then whether
236 // large pages are allocated is up to the filesystem of the backing file.
237 // So UseLargePages is not taken into account for this reservation.
238 char* base = reserve_memory(requested_address, size, alignment, _fd_for_heap, executable);
239 if (base != nullptr) {
240 initialize_members(base, size, alignment, os::vm_page_size(), true, executable);
241 }
242 // Always return, not possible to fall back to reservation not using a file.
243 return;
244 }
245
246 // == Case 2 ==
247 if (use_explicit_large_pages(page_size)) {
248 // System can't commit large pages i.e. use transparent huge pages and
249 // the caller requested large pages. To satisfy this request we use
250 // explicit large pages and these have to be committed up front to ensure
251 // no reservations are lost.
252 do {
253 char* base = reserve_memory_special(requested_address, size, alignment, page_size, executable);
254 if (base != nullptr) {
255 // Successful reservation using large pages.
256 initialize_members(base, size, alignment, page_size, true, executable);
257 return;
258 }
259 page_size = os::page_sizes().next_smaller(page_size);
260 } while (page_size > os::vm_page_size());
261
262 // Failed to reserve explicit large pages, do proper logging.
263 log_on_large_pages_failure(requested_address, size);
264 // Now fall back to normal reservation.
265 assert(page_size == os::vm_page_size(), "inv");
266 }
267
268 // == Case 3 ==
269 char* base = reserve_memory(requested_address, size, alignment, -1, executable);
270 if (base != nullptr) {
271 // Successful mapping.
272 initialize_members(base, size, alignment, page_size, false, executable);
273 }
274 }
275
276 void ReservedSpace::initialize(size_t size,
277 size_t alignment,
278 size_t page_size,
279 char* requested_address,
280 bool executable) {
281 const size_t granularity = os::vm_allocation_granularity();
282 assert((size & (granularity - 1)) == 0,
283 "size not aligned to os::vm_allocation_granularity()");
284 assert((alignment & (granularity - 1)) == 0,
285 "alignment not aligned to os::vm_allocation_granularity()");
286 assert(alignment == 0 || is_power_of_2((intptr_t)alignment),
287 "not a power of 2");
288 assert(page_size >= os::vm_page_size(), "Invalid page size");
289 assert(is_power_of_2(page_size), "Invalid page size");
290
291 clear_members();
292
293 if (size == 0) {
294 return;
295 }
296
297 // Adjust alignment to not be 0.
298 alignment = MAX2(alignment, os::vm_page_size());
299
300 // Reserve the memory.
301 reserve(size, alignment, page_size, requested_address, executable);
302
303 // Check that the requested address is used if given.
304 if (failed_to_reserve_as_requested(_base, requested_address)) {
305 // OS ignored the requested address, release the reservation.
306 release();
307 return;
308 }
309 }
310
311 ReservedSpace ReservedSpace::first_part(size_t partition_size, size_t alignment) {
312 assert(partition_size <= size(), "partition failed");
313 ReservedSpace result(base(), partition_size, alignment, page_size(), special(), executable());
314 return result;
315 }
316
317 ReservedSpace ReservedSpace::last_part(size_t partition_size, size_t alignment) {
318 assert(partition_size <= size(), "partition failed");
319 ReservedSpace result(base() + partition_size, size() - partition_size,
320 alignment, page_size(), special(), executable());
321 return result;
322 }
323
324 ReservedSpace ReservedSpace::partition(size_t offset, size_t partition_size, size_t alignment) {
325 assert(offset + partition_size <= size(), "partition failed");
326 ReservedSpace result(base() + offset, partition_size, alignment, page_size(), special(), executable());
327 return result;
328 }
329
330 size_t ReservedSpace::page_align_size_up(size_t size) {
331 return align_up(size, os::vm_page_size());
332 }
333
334
335 size_t ReservedSpace::page_align_size_down(size_t size) {
336 return align_down(size, os::vm_page_size());
337 }
338
339
340 size_t ReservedSpace::allocation_align_size_up(size_t size) {
341 return align_up(size, os::vm_allocation_granularity());
342 }
343
344 void ReservedSpace::release() {
345 if (is_reserved()) {
346 char *real_base = _base - _noaccess_prefix;
347 const size_t real_size = _size + _noaccess_prefix;
348 if (special()) {
349 if (_fd_for_heap != -1) {
350 os::unmap_memory(real_base, real_size);
351 } else {
352 os::release_memory_special(real_base, real_size);
353 }
354 } else{
355 os::release_memory(real_base, real_size);
356 }
357 clear_members();
358 }
359 }
360
361 // Put a ReservedSpace over an existing range
362 ReservedSpace ReservedSpace::space_for_range(char* base, size_t size, size_t alignment,
363 size_t page_size, bool special, bool executable) {
364 assert(is_aligned(base, os::vm_allocation_granularity()), "Unaligned base");
365 assert(is_aligned(size, os::vm_page_size()), "Unaligned size");
366 assert(os::page_sizes().contains(page_size), "Invalid pagesize");
367 ReservedSpace space;
368 space.initialize_members(base, size, alignment, page_size, special, executable);
369 return space;
370 }
371
372 // Compressed oop support is not relevant in 32bit builds.
373 #ifdef _LP64
374
375 static size_t noaccess_prefix_size(size_t alignment) {
376 return lcm(os::vm_page_size(), alignment);
377 }
378
379 void ReservedHeapSpace::establish_noaccess_prefix() {
380 assert(_alignment >= os::vm_page_size(), "must be at least page size big");
381 _noaccess_prefix = noaccess_prefix_size(_alignment);
382
383 if (base() && base() + _size > (char *)OopEncodingHeapMax) {
384 if (true
385 WIN64_ONLY(&& !UseLargePages)
386 AIX_ONLY(&& (os::Aix::supports_64K_mmap_pages() || os::vm_page_size() == 4*K))) {
387 // Protect memory at the base of the allocated region.
388 // If special, the page was committed (only matters on windows)
389 if (!os::protect_memory(_base, _noaccess_prefix, os::MEM_PROT_NONE, _special)) {
390 fatal("cannot protect protection page");
391 }
392 log_debug(gc, heap, coops)("Protected page at the reserved heap base: "
393 PTR_FORMAT " / " INTX_FORMAT " bytes",
394 p2i(_base),
395 _noaccess_prefix);
396 assert(CompressedOops::use_implicit_null_checks() == true, "not initialized?");
397 } else {
398 CompressedOops::set_use_implicit_null_checks(false);
399 }
400 }
401
402 _base += _noaccess_prefix;
403 _size -= _noaccess_prefix;
404 assert(((uintptr_t)_base % _alignment == 0), "must be exactly of required alignment");
405 }
406
407 // Tries to allocate memory of size 'size' at address requested_address with alignment 'alignment'.
408 // Does not check whether the reserved memory actually is at requested_address, as the memory returned
409 // might still fulfill the wishes of the caller.
410 // Assures the memory is aligned to 'alignment'.
411 // NOTE: If ReservedHeapSpace already points to some reserved memory this is freed, first.
412 void ReservedHeapSpace::try_reserve_heap(size_t size,
413 size_t alignment,
414 size_t page_size,
415 char* requested_address) {
416 if (_base != nullptr) {
417 // We tried before, but we didn't like the address delivered.
418 release();
419 }
420
421 // Try to reserve the memory for the heap.
422 log_trace(gc, heap, coops)("Trying to allocate at address " PTR_FORMAT
423 " heap of size " SIZE_FORMAT_X,
424 p2i(requested_address),
425 size);
426
427 reserve(size, alignment, page_size, requested_address, false);
428
429 // Check alignment constraints.
430 if (is_reserved() && !is_aligned(_base, _alignment)) {
431 // Base not aligned, retry.
432 release();
433 }
434 }
435
436 void ReservedHeapSpace::try_reserve_range(char *highest_start,
437 char *lowest_start,
438 size_t attach_point_alignment,
439 char *aligned_heap_base_min_address,
440 char *upper_bound,
441 size_t size,
442 size_t alignment,
443 size_t page_size) {
444 const size_t attach_range = highest_start - lowest_start;
445 // Cap num_attempts at possible number.
446 // At least one is possible even for 0 sized attach range.
447 const uint64_t num_attempts_possible = (attach_range / attach_point_alignment) + 1;
448 const uint64_t num_attempts_to_try = MIN2((uint64_t)HeapSearchSteps, num_attempts_possible);
449
450 const size_t stepsize = (attach_range == 0) ? // Only one try.
451 (size_t) highest_start : align_up(attach_range / num_attempts_to_try, attach_point_alignment);
452
453 // Try attach points from top to bottom.
454 char* attach_point = highest_start;
455 while (attach_point >= lowest_start &&
456 attach_point <= highest_start && // Avoid wrap around.
457 ((_base == nullptr) ||
458 (_base < aligned_heap_base_min_address || _base + size > upper_bound))) {
459 try_reserve_heap(size, alignment, page_size, attach_point);
460 attach_point -= stepsize;
461 }
462 }
463
464 #define SIZE_64K ((uint64_t) UCONST64( 0x10000))
465 #define SIZE_256M ((uint64_t) UCONST64( 0x10000000))
466 #define SIZE_32G ((uint64_t) UCONST64( 0x800000000))
467
468 // Helper for heap allocation. Returns an array with addresses
469 // (OS-specific) which are suited for disjoint base mode. Array is
470 // null terminated.
471 static char** get_attach_addresses_for_disjoint_mode() {
472 static uint64_t addresses[] = {
473 2 * SIZE_32G,
474 3 * SIZE_32G,
475 4 * SIZE_32G,
476 8 * SIZE_32G,
477 10 * SIZE_32G,
478 1 * SIZE_64K * SIZE_32G,
479 2 * SIZE_64K * SIZE_32G,
480 3 * SIZE_64K * SIZE_32G,
481 4 * SIZE_64K * SIZE_32G,
482 16 * SIZE_64K * SIZE_32G,
483 32 * SIZE_64K * SIZE_32G,
484 34 * SIZE_64K * SIZE_32G,
485 0
486 };
487
488 // Sort out addresses smaller than HeapBaseMinAddress. This assumes
489 // the array is sorted.
490 uint i = 0;
491 while (addresses[i] != 0 &&
492 (addresses[i] < OopEncodingHeapMax || addresses[i] < HeapBaseMinAddress)) {
493 i++;
494 }
495 uint start = i;
496
497 // Avoid more steps than requested.
498 i = 0;
499 while (addresses[start+i] != 0) {
500 if (i == HeapSearchSteps) {
501 addresses[start+i] = 0;
502 break;
503 }
504 i++;
505 }
506
507 return (char**) &addresses[start];
508 }
509
510 void ReservedHeapSpace::initialize_compressed_heap(const size_t size, size_t alignment, size_t page_size) {
511 guarantee(size + noaccess_prefix_size(alignment) <= OopEncodingHeapMax,
512 "can not allocate compressed oop heap for this size");
513 guarantee(alignment == MAX2(alignment, os::vm_page_size()), "alignment too small");
514
515 const size_t granularity = os::vm_allocation_granularity();
516 assert((size & (granularity - 1)) == 0,
517 "size not aligned to os::vm_allocation_granularity()");
518 assert((alignment & (granularity - 1)) == 0,
519 "alignment not aligned to os::vm_allocation_granularity()");
520 assert(alignment == 0 || is_power_of_2((intptr_t)alignment),
521 "not a power of 2");
522
523 // The necessary attach point alignment for generated wish addresses.
524 // This is needed to increase the chance of attaching for mmap and shmat.
525 // AIX is the only platform that uses System V shm for reserving virtual memory.
526 // In this case, the required alignment of the allocated size (64K) and the alignment
527 // of possible start points of the memory region (256M) differ.
528 // This is not reflected by os_allocation_granularity().
529 // The logic here is dual to the one in pd_reserve_memory in os_aix.cpp
530 const size_t os_attach_point_alignment =
531 AIX_ONLY(os::vm_page_size() == 4*K ? 4*K : 256*M)
532 NOT_AIX(os::vm_allocation_granularity());
533
534 const size_t attach_point_alignment = lcm(alignment, os_attach_point_alignment);
535
536 char *aligned_heap_base_min_address = (char *)align_up((void *)HeapBaseMinAddress, alignment);
537 size_t noaccess_prefix = ((aligned_heap_base_min_address + size) > (char*)OopEncodingHeapMax) ?
538 noaccess_prefix_size(alignment) : 0;
539
540 // Attempt to alloc at user-given address.
541 if (!FLAG_IS_DEFAULT(HeapBaseMinAddress)) {
542 try_reserve_heap(size + noaccess_prefix, alignment, page_size, aligned_heap_base_min_address);
543 if (_base != aligned_heap_base_min_address) { // Enforce this exact address.
544 release();
545 }
546 }
547
548 // Keep heap at HeapBaseMinAddress.
549 if (_base == nullptr) {
550
551 // Try to allocate the heap at addresses that allow efficient oop compression.
552 // Different schemes are tried, in order of decreasing optimization potential.
553 //
554 // For this, try_reserve_heap() is called with the desired heap base addresses.
555 // A call into the os layer to allocate at a given address can return memory
556 // at a different address than requested. Still, this might be memory at a useful
557 // address. try_reserve_heap() always returns this allocated memory, as only here
558 // the criteria for a good heap are checked.
559
560 // Attempt to allocate so that we can run without base and scale (32-Bit unscaled compressed oops).
561 // Give it several tries from top of range to bottom.
562 if (aligned_heap_base_min_address + size <= (char *)UnscaledOopHeapMax) {
563
564 // Calc address range within we try to attach (range of possible start addresses).
565 char* const highest_start = align_down((char *)UnscaledOopHeapMax - size, attach_point_alignment);
566 char* const lowest_start = align_up(aligned_heap_base_min_address, attach_point_alignment);
567 try_reserve_range(highest_start, lowest_start, attach_point_alignment,
568 aligned_heap_base_min_address, (char *)UnscaledOopHeapMax, size, alignment, page_size);
569 }
570
571 // zerobased: Attempt to allocate in the lower 32G.
572 char *zerobased_max = (char *)OopEncodingHeapMax;
573
574 // Give it several tries from top of range to bottom.
575 if (aligned_heap_base_min_address + size <= zerobased_max && // Zerobased theoretical possible.
576 ((_base == nullptr) || // No previous try succeeded.
577 (_base + size > zerobased_max))) { // Unscaled delivered an arbitrary address.
578
579 // Calc address range within we try to attach (range of possible start addresses).
580 char *const highest_start = align_down(zerobased_max - size, attach_point_alignment);
581 // Need to be careful about size being guaranteed to be less
582 // than UnscaledOopHeapMax due to type constraints.
583 char *lowest_start = aligned_heap_base_min_address;
584 uint64_t unscaled_end = UnscaledOopHeapMax - size;
585 if (unscaled_end < UnscaledOopHeapMax) { // unscaled_end wrapped if size is large
586 lowest_start = MAX2(lowest_start, (char*)unscaled_end);
587 }
588 lowest_start = align_up(lowest_start, attach_point_alignment);
589 try_reserve_range(highest_start, lowest_start, attach_point_alignment,
590 aligned_heap_base_min_address, zerobased_max, size, alignment, page_size);
591 }
592
593 // Now we go for heaps with base != 0. We need a noaccess prefix to efficiently
594 // implement null checks.
595 noaccess_prefix = noaccess_prefix_size(alignment);
596
597 // Try to attach at addresses that are aligned to OopEncodingHeapMax. Disjointbase mode.
598 char** addresses = get_attach_addresses_for_disjoint_mode();
599 int i = 0;
600 while ((addresses[i] != nullptr) && // End of array not yet reached.
601 ((_base == nullptr) || // No previous try succeeded.
602 (_base + size > (char *)OopEncodingHeapMax && // Not zerobased or unscaled address.
603 !CompressedOops::is_disjoint_heap_base_address((address)_base)))) { // Not disjoint address.
604 char* const attach_point = addresses[i];
605 assert(attach_point >= aligned_heap_base_min_address, "Flag support broken");
606 try_reserve_heap(size + noaccess_prefix, alignment, page_size, attach_point);
607 i++;
608 }
609
610 // Last, desperate try without any placement.
611 if (_base == nullptr) {
612 log_trace(gc, heap, coops)("Trying to allocate at address null heap of size " SIZE_FORMAT_X, size + noaccess_prefix);
613 initialize(size + noaccess_prefix, alignment, page_size, nullptr, false);
614 }
615 }
616 }
617
618 #endif // _LP64
619
620 ReservedHeapSpace::ReservedHeapSpace(size_t size, size_t alignment, size_t page_size, const char* heap_allocation_directory) : ReservedSpace() {
621
622 if (size == 0) {
623 return;
624 }
625
626 if (heap_allocation_directory != nullptr) {
627 _fd_for_heap = os::create_file_for_heap(heap_allocation_directory);
628 if (_fd_for_heap == -1) {
629 vm_exit_during_initialization(
630 err_msg("Could not create file for Heap at location %s", heap_allocation_directory));
631 }
632 // When there is a backing file directory for this space then whether
633 // large pages are allocated is up to the filesystem of the backing file.
634 // If requested, let the user know that explicit large pages can't be used.
635 if (use_explicit_large_pages(page_size) && large_pages_requested()) {
636 log_debug(gc, heap)("Cannot allocate explicit large pages for Java Heap when AllocateHeapAt option is set.");
637 }
638 }
639
640 // Heap size should be aligned to alignment, too.
641 guarantee(is_aligned(size, alignment), "set by caller");
642
643 if (UseCompressedOops) {
644 #ifdef _LP64
645 initialize_compressed_heap(size, alignment, page_size);
646 if (_size > size) {
647 // We allocated heap with noaccess prefix.
648 // It can happen we get a zerobased/unscaled heap with noaccess prefix,
649 // if we had to try at arbitrary address.
650 establish_noaccess_prefix();
651 }
652 #else
653 ShouldNotReachHere();
654 #endif // _LP64
655 } else {
656 initialize(size, alignment, page_size, nullptr, false);
657 }
658
659 assert(markWord::encode_pointer_as_mark(_base).decode_pointer() == _base,
660 "area must be distinguishable from marks for mark-sweep");
661 assert(markWord::encode_pointer_as_mark(&_base[size]).decode_pointer() == &_base[size],
662 "area must be distinguishable from marks for mark-sweep");
663
664 if (base() != nullptr) {
665 MemTracker::record_virtual_memory_tag((address)base(), mtJavaHeap);
666 }
667
668 if (_fd_for_heap != -1) {
669 ::close(_fd_for_heap);
670 }
671 }
672
673 MemRegion ReservedHeapSpace::region() const {
674 return MemRegion((HeapWord*)base(), (HeapWord*)end());
675 }
676
677 // Reserve space for code segment. Same as Java heap only we mark this as
678 // executable.
679 ReservedCodeSpace::ReservedCodeSpace(size_t r_size,
680 size_t rs_align,
681 size_t rs_page_size) : ReservedSpace() {
682 initialize(r_size, rs_align, rs_page_size, /*requested address*/ nullptr, /*executable*/ true);
683 MemTracker::record_virtual_memory_tag((address)base(), mtCode);
684 }
685
686 // VirtualSpace
687
688 VirtualSpace::VirtualSpace() {
689 _low_boundary = nullptr;
690 _high_boundary = nullptr;
691 _low = nullptr;
692 _high = nullptr;
693 _lower_high = nullptr;
694 _middle_high = nullptr;
695 _upper_high = nullptr;
696 _lower_high_boundary = nullptr;
697 _middle_high_boundary = nullptr;
698 _upper_high_boundary = nullptr;
699 _lower_alignment = 0;
700 _middle_alignment = 0;
701 _upper_alignment = 0;
702 _special = false;
703 _executable = false;
704 }
705
706
707 bool VirtualSpace::initialize(ReservedSpace rs, size_t committed_size) {
708 const size_t max_commit_granularity = os::page_size_for_region_unaligned(rs.size(), 1);
709 return initialize_with_granularity(rs, committed_size, max_commit_granularity);
710 }
711
712 bool VirtualSpace::initialize_with_granularity(ReservedSpace rs, size_t committed_size, size_t max_commit_granularity) {
713 if(!rs.is_reserved()) return false; // allocation failed.
714 assert(_low_boundary == nullptr, "VirtualSpace already initialized");
715 assert(max_commit_granularity > 0, "Granularity must be non-zero.");
716
717 _low_boundary = rs.base();
718 _high_boundary = low_boundary() + rs.size();
719
720 _low = low_boundary();
721 _high = low();
722
723 _special = rs.special();
724 _executable = rs.executable();
725
726 // When a VirtualSpace begins life at a large size, make all future expansion
727 // and shrinking occur aligned to a granularity of large pages. This avoids
728 // fragmentation of physical addresses that inhibits the use of large pages
729 // by the OS virtual memory system. Empirically, we see that with a 4MB
730 // page size, the only spaces that get handled this way are codecache and
731 // the heap itself, both of which provide a substantial performance
732 // boost in many benchmarks when covered by large pages.
733 //
734 // No attempt is made to force large page alignment at the very top and
735 // bottom of the space if they are not aligned so already.
736 _lower_alignment = os::vm_page_size();
737 _middle_alignment = max_commit_granularity;
738 _upper_alignment = os::vm_page_size();
739
740 // End of each region
741 _lower_high_boundary = align_up(low_boundary(), middle_alignment());
742 _middle_high_boundary = align_down(high_boundary(), middle_alignment());
743 _upper_high_boundary = high_boundary();
744
745 // High address of each region
746 _lower_high = low_boundary();
747 _middle_high = lower_high_boundary();
748 _upper_high = middle_high_boundary();
749
750 // commit to initial size
751 if (committed_size > 0) {
752 if (!expand_by(committed_size)) {
753 return false;
754 }
755 }
756 return true;
757 }
758
759
760 VirtualSpace::~VirtualSpace() {
761 release();
762 }
763
764
765 void VirtualSpace::release() {
766 // This does not release memory it reserved.
767 // Caller must release via rs.release();
768 _low_boundary = nullptr;
769 _high_boundary = nullptr;
770 _low = nullptr;
771 _high = nullptr;
772 _lower_high = nullptr;
773 _middle_high = nullptr;
774 _upper_high = nullptr;
775 _lower_high_boundary = nullptr;
776 _middle_high_boundary = nullptr;
777 _upper_high_boundary = nullptr;
778 _lower_alignment = 0;
779 _middle_alignment = 0;
780 _upper_alignment = 0;
781 _special = false;
782 _executable = false;
783 }
784
785
786 size_t VirtualSpace::committed_size() const {
787 return pointer_delta(high(), low(), sizeof(char));
788 }
789
790
791 size_t VirtualSpace::reserved_size() const {
792 return pointer_delta(high_boundary(), low_boundary(), sizeof(char));
793 }
794
795
796 size_t VirtualSpace::uncommitted_size() const {
797 return reserved_size() - committed_size();
798 }
799
800 size_t VirtualSpace::actual_committed_size() const {
801 // Special VirtualSpaces commit all reserved space up front.
802 if (special()) {
803 return reserved_size();
804 }
805
806 size_t committed_low = pointer_delta(_lower_high, _low_boundary, sizeof(char));
807 size_t committed_middle = pointer_delta(_middle_high, _lower_high_boundary, sizeof(char));
808 size_t committed_high = pointer_delta(_upper_high, _middle_high_boundary, sizeof(char));
809
810 #ifdef ASSERT
811 size_t lower = pointer_delta(_lower_high_boundary, _low_boundary, sizeof(char));
812 size_t middle = pointer_delta(_middle_high_boundary, _lower_high_boundary, sizeof(char));
813 size_t upper = pointer_delta(_upper_high_boundary, _middle_high_boundary, sizeof(char));
814
815 if (committed_high > 0) {
816 assert(committed_low == lower, "Must be");
817 assert(committed_middle == middle, "Must be");
818 }
819
820 if (committed_middle > 0) {
821 assert(committed_low == lower, "Must be");
822 }
823 if (committed_middle < middle) {
824 assert(committed_high == 0, "Must be");
825 }
826
827 if (committed_low < lower) {
828 assert(committed_high == 0, "Must be");
829 assert(committed_middle == 0, "Must be");
830 }
831 #endif
832
833 return committed_low + committed_middle + committed_high;
834 }
835
836
837 bool VirtualSpace::contains(const void* p) const {
838 return low() <= (const char*) p && (const char*) p < high();
839 }
840
841 static void pretouch_expanded_memory(void* start, void* end) {
842 assert(is_aligned(start, os::vm_page_size()), "Unexpected alignment");
843 assert(is_aligned(end, os::vm_page_size()), "Unexpected alignment");
844
845 os::pretouch_memory(start, end);
846 }
847
848 static bool commit_expanded(char* start, size_t size, size_t alignment, bool pre_touch, bool executable) {
849 if (os::commit_memory(start, size, alignment, executable)) {
850 if (pre_touch || AlwaysPreTouch) {
851 pretouch_expanded_memory(start, start + size);
852 }
853 return true;
854 }
855
856 debug_only(warning(
857 "INFO: os::commit_memory(" PTR_FORMAT ", " PTR_FORMAT
858 " size=" SIZE_FORMAT ", executable=%d) failed",
859 p2i(start), p2i(start + size), size, executable);)
860
861 return false;
862 }
863
864 /*
865 First we need to determine if a particular virtual space is using large
866 pages. This is done at the initialize function and only virtual spaces
867 that are larger than LargePageSizeInBytes use large pages. Once we
868 have determined this, all expand_by and shrink_by calls must grow and
869 shrink by large page size chunks. If a particular request
870 is within the current large page, the call to commit and uncommit memory
871 can be ignored. In the case that the low and high boundaries of this
872 space is not large page aligned, the pages leading to the first large
873 page address and the pages after the last large page address must be
874 allocated with default pages.
875 */
876 bool VirtualSpace::expand_by(size_t bytes, bool pre_touch) {
877 if (uncommitted_size() < bytes) {
878 return false;
879 }
880
881 if (special()) {
882 // don't commit memory if the entire space is pinned in memory
883 _high += bytes;
884 return true;
885 }
886
887 char* previous_high = high();
888 char* unaligned_new_high = high() + bytes;
889 assert(unaligned_new_high <= high_boundary(), "cannot expand by more than upper boundary");
890
891 // Calculate where the new high for each of the regions should be. If
892 // the low_boundary() and high_boundary() are LargePageSizeInBytes aligned
893 // then the unaligned lower and upper new highs would be the
894 // lower_high() and upper_high() respectively.
895 char* unaligned_lower_new_high = MIN2(unaligned_new_high, lower_high_boundary());
896 char* unaligned_middle_new_high = MIN2(unaligned_new_high, middle_high_boundary());
897 char* unaligned_upper_new_high = MIN2(unaligned_new_high, upper_high_boundary());
898
899 // Align the new highs based on the regions alignment. lower and upper
900 // alignment will always be default page size. middle alignment will be
901 // LargePageSizeInBytes if the actual size of the virtual space is in
902 // fact larger than LargePageSizeInBytes.
903 char* aligned_lower_new_high = align_up(unaligned_lower_new_high, lower_alignment());
904 char* aligned_middle_new_high = align_up(unaligned_middle_new_high, middle_alignment());
905 char* aligned_upper_new_high = align_up(unaligned_upper_new_high, upper_alignment());
906
907 // Determine which regions need to grow in this expand_by call.
908 // If you are growing in the lower region, high() must be in that
909 // region so calculate the size based on high(). For the middle and
910 // upper regions, determine the starting point of growth based on the
911 // location of high(). By getting the MAX of the region's low address
912 // (or the previous region's high address) and high(), we can tell if it
913 // is an intra or inter region growth.
914 size_t lower_needs = 0;
915 if (aligned_lower_new_high > lower_high()) {
916 lower_needs = pointer_delta(aligned_lower_new_high, lower_high(), sizeof(char));
917 }
918 size_t middle_needs = 0;
919 if (aligned_middle_new_high > middle_high()) {
920 middle_needs = pointer_delta(aligned_middle_new_high, middle_high(), sizeof(char));
921 }
922 size_t upper_needs = 0;
923 if (aligned_upper_new_high > upper_high()) {
924 upper_needs = pointer_delta(aligned_upper_new_high, upper_high(), sizeof(char));
925 }
926
927 // Check contiguity.
928 assert(low_boundary() <= lower_high() && lower_high() <= lower_high_boundary(),
929 "high address must be contained within the region");
930 assert(lower_high_boundary() <= middle_high() && middle_high() <= middle_high_boundary(),
931 "high address must be contained within the region");
932 assert(middle_high_boundary() <= upper_high() && upper_high() <= upper_high_boundary(),
933 "high address must be contained within the region");
934
935 // Commit regions
936 if (lower_needs > 0) {
937 assert(lower_high() + lower_needs <= lower_high_boundary(), "must not expand beyond region");
938 if (!commit_expanded(lower_high(), lower_needs, _lower_alignment, pre_touch, _executable)) {
939 return false;
940 }
941 _lower_high += lower_needs;
942 }
943
944 if (middle_needs > 0) {
945 assert(middle_high() + middle_needs <= middle_high_boundary(), "must not expand beyond region");
946 if (!commit_expanded(middle_high(), middle_needs, _middle_alignment, pre_touch, _executable)) {
947 return false;
948 }
949 _middle_high += middle_needs;
950 }
951
952 if (upper_needs > 0) {
953 assert(upper_high() + upper_needs <= upper_high_boundary(), "must not expand beyond region");
954 if (!commit_expanded(upper_high(), upper_needs, _upper_alignment, pre_touch, _executable)) {
955 return false;
956 }
957 _upper_high += upper_needs;
958 }
959
960 _high += bytes;
961 return true;
962 }
963
964 // A page is uncommitted if the contents of the entire page is deemed unusable.
965 // Continue to decrement the high() pointer until it reaches a page boundary
966 // in which case that particular page can now be uncommitted.
967 void VirtualSpace::shrink_by(size_t size) {
968 if (committed_size() < size)
969 fatal("Cannot shrink virtual space to negative size");
970
971 if (special()) {
972 // don't uncommit if the entire space is pinned in memory
973 _high -= size;
974 return;
975 }
976
977 char* unaligned_new_high = high() - size;
978 assert(unaligned_new_high >= low_boundary(), "cannot shrink past lower boundary");
979
980 // Calculate new unaligned address
981 char* unaligned_upper_new_high =
982 MAX2(unaligned_new_high, middle_high_boundary());
983 char* unaligned_middle_new_high =
984 MAX2(unaligned_new_high, lower_high_boundary());
985 char* unaligned_lower_new_high =
986 MAX2(unaligned_new_high, low_boundary());
987
988 // Align address to region's alignment
989 char* aligned_upper_new_high = align_up(unaligned_upper_new_high, upper_alignment());
990 char* aligned_middle_new_high = align_up(unaligned_middle_new_high, middle_alignment());
991 char* aligned_lower_new_high = align_up(unaligned_lower_new_high, lower_alignment());
992
993 // Determine which regions need to shrink
994 size_t upper_needs = 0;
995 if (aligned_upper_new_high < upper_high()) {
996 upper_needs =
997 pointer_delta(upper_high(), aligned_upper_new_high, sizeof(char));
998 }
999 size_t middle_needs = 0;
1000 if (aligned_middle_new_high < middle_high()) {
1001 middle_needs =
1002 pointer_delta(middle_high(), aligned_middle_new_high, sizeof(char));
1003 }
1004 size_t lower_needs = 0;
1005 if (aligned_lower_new_high < lower_high()) {
1006 lower_needs =
1007 pointer_delta(lower_high(), aligned_lower_new_high, sizeof(char));
1008 }
1009
1010 // Check contiguity.
1011 assert(middle_high_boundary() <= upper_high() &&
1012 upper_high() <= upper_high_boundary(),
1013 "high address must be contained within the region");
1014 assert(lower_high_boundary() <= middle_high() &&
1015 middle_high() <= middle_high_boundary(),
1016 "high address must be contained within the region");
1017 assert(low_boundary() <= lower_high() &&
1018 lower_high() <= lower_high_boundary(),
1019 "high address must be contained within the region");
1020
1021 // Uncommit
1022 if (upper_needs > 0) {
1023 assert(middle_high_boundary() <= aligned_upper_new_high &&
1024 aligned_upper_new_high + upper_needs <= upper_high_boundary(),
1025 "must not shrink beyond region");
1026 if (!os::uncommit_memory(aligned_upper_new_high, upper_needs, _executable)) {
1027 debug_only(warning("os::uncommit_memory failed"));
1028 return;
1029 } else {
1030 _upper_high -= upper_needs;
1031 }
1032 }
1033 if (middle_needs > 0) {
1034 assert(lower_high_boundary() <= aligned_middle_new_high &&
1035 aligned_middle_new_high + middle_needs <= middle_high_boundary(),
1036 "must not shrink beyond region");
1037 if (!os::uncommit_memory(aligned_middle_new_high, middle_needs, _executable)) {
1038 debug_only(warning("os::uncommit_memory failed"));
1039 return;
1040 } else {
1041 _middle_high -= middle_needs;
1042 }
1043 }
1044 if (lower_needs > 0) {
1045 assert(low_boundary() <= aligned_lower_new_high &&
1046 aligned_lower_new_high + lower_needs <= lower_high_boundary(),
1047 "must not shrink beyond region");
1048 if (!os::uncommit_memory(aligned_lower_new_high, lower_needs, _executable)) {
1049 debug_only(warning("os::uncommit_memory failed"));
1050 return;
1051 } else {
1052 _lower_high -= lower_needs;
1053 }
1054 }
1055
1056 _high -= size;
1057 }
1058
1059 #ifndef PRODUCT
1060 void VirtualSpace::check_for_contiguity() {
1061 // Check contiguity.
1062 assert(low_boundary() <= lower_high() &&
1063 lower_high() <= lower_high_boundary(),
1064 "high address must be contained within the region");
1065 assert(lower_high_boundary() <= middle_high() &&
1066 middle_high() <= middle_high_boundary(),
1067 "high address must be contained within the region");
1068 assert(middle_high_boundary() <= upper_high() &&
1069 upper_high() <= upper_high_boundary(),
1070 "high address must be contained within the region");
1071 assert(low() >= low_boundary(), "low");
1072 assert(low_boundary() <= lower_high_boundary(), "lower high boundary");
1073 assert(upper_high_boundary() <= high_boundary(), "upper high boundary");
1074 assert(high() <= upper_high(), "upper high");
1075 }
1076
1077 void VirtualSpace::print_on(outputStream* out) const {
1078 out->print ("Virtual space:");
1079 if (special()) out->print(" (pinned in memory)");
1080 out->cr();
1081 out->print_cr(" - committed: " SIZE_FORMAT, committed_size());
1082 out->print_cr(" - reserved: " SIZE_FORMAT, reserved_size());
1083 out->print_cr(" - [low, high]: [" PTR_FORMAT ", " PTR_FORMAT "]", p2i(low()), p2i(high()));
1084 out->print_cr(" - [low_b, high_b]: [" PTR_FORMAT ", " PTR_FORMAT "]", p2i(low_boundary()), p2i(high_boundary()));
1085 }
1086
1087 void VirtualSpace::print() const {
1088 print_on(tty);
1089 }
1090
1091 #endif