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.
22 *
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 static size_t noaccess_prefix_size(size_t alignment) {
373 return lcm(os::vm_page_size(), alignment);
374 }
375
376 void ReservedHeapSpace::establish_noaccess_prefix() {
377 assert(_alignment >= os::vm_page_size(), "must be at least page size big");
378 _noaccess_prefix = noaccess_prefix_size(_alignment);
379
380 if (base() && base() + _size > (char *)OopEncodingHeapMax) {
381 if (true
382 WIN64_ONLY(&& !UseLargePages)
383 AIX_ONLY(&& (os::Aix::supports_64K_mmap_pages() || os::vm_page_size() == 4*K))) {
384 // Protect memory at the base of the allocated region.
385 // If special, the page was committed (only matters on windows)
386 if (!os::protect_memory(_base, _noaccess_prefix, os::MEM_PROT_NONE, _special)) {
387 fatal("cannot protect protection page");
388 }
389 log_debug(gc, heap, coops)("Protected page at the reserved heap base: "
390 PTR_FORMAT " / " INTX_FORMAT " bytes",
391 p2i(_base),
392 _noaccess_prefix);
393 assert(CompressedOops::use_implicit_null_checks() == true, "not initialized?");
394 } else {
395 CompressedOops::set_use_implicit_null_checks(false);
396 }
397 }
398
399 _base += _noaccess_prefix;
400 _size -= _noaccess_prefix;
401 assert(((uintptr_t)_base % _alignment == 0), "must be exactly of required alignment");
402 }
403
404 // Tries to allocate memory of size 'size' at address requested_address with alignment 'alignment'.
405 // Does not check whether the reserved memory actually is at requested_address, as the memory returned
406 // might still fulfill the wishes of the caller.
407 // Assures the memory is aligned to 'alignment'.
408 // NOTE: If ReservedHeapSpace already points to some reserved memory this is freed, first.
409 void ReservedHeapSpace::try_reserve_heap(size_t size,
410 size_t alignment,
411 size_t page_size,
412 char* requested_address) {
413 if (_base != nullptr) {
414 // We tried before, but we didn't like the address delivered.
415 release();
416 }
417
418 // Try to reserve the memory for the heap.
419 log_trace(gc, heap, coops)("Trying to allocate at address " PTR_FORMAT
420 " heap of size " SIZE_FORMAT_X,
421 p2i(requested_address),
422 size);
423
424 reserve(size, alignment, page_size, requested_address, false);
425
426 // Check alignment constraints.
427 if (is_reserved() && !is_aligned(_base, _alignment)) {
428 // Base not aligned, retry.
429 release();
430 }
431 }
432
433 void ReservedHeapSpace::try_reserve_range(char *highest_start,
434 char *lowest_start,
435 size_t attach_point_alignment,
436 char *aligned_heap_base_min_address,
437 char *upper_bound,
438 size_t size,
439 size_t alignment,
440 size_t page_size) {
441 const size_t attach_range = highest_start - lowest_start;
442 // Cap num_attempts at possible number.
443 // At least one is possible even for 0 sized attach range.
444 const uint64_t num_attempts_possible = (attach_range / attach_point_alignment) + 1;
445 const uint64_t num_attempts_to_try = MIN2((uint64_t)HeapSearchSteps, num_attempts_possible);
446
447 const size_t stepsize = (attach_range == 0) ? // Only one try.
448 (size_t) highest_start : align_up(attach_range / num_attempts_to_try, attach_point_alignment);
449
450 // Try attach points from top to bottom.
451 char* attach_point = highest_start;
452 while (attach_point >= lowest_start &&
453 attach_point <= highest_start && // Avoid wrap around.
454 ((_base == nullptr) ||
455 (_base < aligned_heap_base_min_address || _base + size > upper_bound))) {
456 try_reserve_heap(size, alignment, page_size, attach_point);
457 attach_point -= stepsize;
458 }
459 }
460
461 #define SIZE_64K ((uint64_t) UCONST64( 0x10000))
462 #define SIZE_256M ((uint64_t) UCONST64( 0x10000000))
463 #define SIZE_32G ((uint64_t) UCONST64( 0x800000000))
464
465 // Helper for heap allocation. Returns an array with addresses
466 // (OS-specific) which are suited for disjoint base mode. Array is
467 // null terminated.
468 static char** get_attach_addresses_for_disjoint_mode() {
469 static uint64_t addresses[] = {
470 2 * SIZE_32G,
471 3 * SIZE_32G,
472 4 * SIZE_32G,
473 8 * SIZE_32G,
474 10 * SIZE_32G,
475 1 * SIZE_64K * SIZE_32G,
476 2 * SIZE_64K * SIZE_32G,
477 3 * SIZE_64K * SIZE_32G,
478 4 * SIZE_64K * SIZE_32G,
479 16 * SIZE_64K * SIZE_32G,
480 32 * SIZE_64K * SIZE_32G,
481 34 * SIZE_64K * SIZE_32G,
482 0
483 };
484
485 // Sort out addresses smaller than HeapBaseMinAddress. This assumes
486 // the array is sorted.
487 uint i = 0;
488 while (addresses[i] != 0 &&
489 (addresses[i] < OopEncodingHeapMax || addresses[i] < HeapBaseMinAddress)) {
490 i++;
491 }
492 uint start = i;
493
494 // Avoid more steps than requested.
495 i = 0;
496 while (addresses[start+i] != 0) {
497 if (i == HeapSearchSteps) {
498 addresses[start+i] = 0;
499 break;
500 }
501 i++;
502 }
503
504 return (char**) &addresses[start];
505 }
506
507 void ReservedHeapSpace::initialize_compressed_heap(const size_t size, size_t alignment, size_t page_size) {
508 guarantee(size + noaccess_prefix_size(alignment) <= OopEncodingHeapMax,
509 "can not allocate compressed oop heap for this size");
510 guarantee(alignment == MAX2(alignment, os::vm_page_size()), "alignment too small");
511
512 const size_t granularity = os::vm_allocation_granularity();
513 assert((size & (granularity - 1)) == 0,
514 "size not aligned to os::vm_allocation_granularity()");
515 assert((alignment & (granularity - 1)) == 0,
516 "alignment not aligned to os::vm_allocation_granularity()");
517 assert(alignment == 0 || is_power_of_2((intptr_t)alignment),
518 "not a power of 2");
519
520 // The necessary attach point alignment for generated wish addresses.
521 // This is needed to increase the chance of attaching for mmap and shmat.
522 // AIX is the only platform that uses System V shm for reserving virtual memory.
523 // In this case, the required alignment of the allocated size (64K) and the alignment
524 // of possible start points of the memory region (256M) differ.
525 // This is not reflected by os_allocation_granularity().
526 // The logic here is dual to the one in pd_reserve_memory in os_aix.cpp
527 const size_t os_attach_point_alignment =
528 AIX_ONLY(os::vm_page_size() == 4*K ? 4*K : 256*M)
529 NOT_AIX(os::vm_allocation_granularity());
530
531 const size_t attach_point_alignment = lcm(alignment, os_attach_point_alignment);
532
533 char *aligned_heap_base_min_address = (char *)align_up((void *)HeapBaseMinAddress, alignment);
534 size_t noaccess_prefix = ((aligned_heap_base_min_address + size) > (char*)OopEncodingHeapMax) ?
535 noaccess_prefix_size(alignment) : 0;
536
537 // Attempt to alloc at user-given address.
538 if (!FLAG_IS_DEFAULT(HeapBaseMinAddress)) {
539 try_reserve_heap(size + noaccess_prefix, alignment, page_size, aligned_heap_base_min_address);
540 if (_base != aligned_heap_base_min_address) { // Enforce this exact address.
541 release();
542 }
543 }
544
545 // Keep heap at HeapBaseMinAddress.
546 if (_base == nullptr) {
547
548 // Try to allocate the heap at addresses that allow efficient oop compression.
549 // Different schemes are tried, in order of decreasing optimization potential.
550 //
551 // For this, try_reserve_heap() is called with the desired heap base addresses.
552 // A call into the os layer to allocate at a given address can return memory
553 // at a different address than requested. Still, this might be memory at a useful
554 // address. try_reserve_heap() always returns this allocated memory, as only here
555 // the criteria for a good heap are checked.
556
557 // Attempt to allocate so that we can run without base and scale (32-Bit unscaled compressed oops).
558 // Give it several tries from top of range to bottom.
559 if (aligned_heap_base_min_address + size <= (char *)UnscaledOopHeapMax) {
560
561 // Calc address range within we try to attach (range of possible start addresses).
562 char* const highest_start = align_down((char *)UnscaledOopHeapMax - size, attach_point_alignment);
563 char* const lowest_start = align_up(aligned_heap_base_min_address, attach_point_alignment);
564 try_reserve_range(highest_start, lowest_start, attach_point_alignment,
565 aligned_heap_base_min_address, (char *)UnscaledOopHeapMax, size, alignment, page_size);
566 }
567
568 // zerobased: Attempt to allocate in the lower 32G.
569 char *zerobased_max = (char *)OopEncodingHeapMax;
570
571 // Give it several tries from top of range to bottom.
572 if (aligned_heap_base_min_address + size <= zerobased_max && // Zerobased theoretical possible.
573 ((_base == nullptr) || // No previous try succeeded.
574 (_base + size > zerobased_max))) { // Unscaled delivered an arbitrary address.
575
576 // Calc address range within we try to attach (range of possible start addresses).
577 char *const highest_start = align_down(zerobased_max - size, attach_point_alignment);
578 // Need to be careful about size being guaranteed to be less
579 // than UnscaledOopHeapMax due to type constraints.
580 char *lowest_start = aligned_heap_base_min_address;
581 uint64_t unscaled_end = UnscaledOopHeapMax - size;
582 if (unscaled_end < UnscaledOopHeapMax) { // unscaled_end wrapped if size is large
583 lowest_start = MAX2(lowest_start, (char*)unscaled_end);
584 }
585 lowest_start = align_up(lowest_start, attach_point_alignment);
586 try_reserve_range(highest_start, lowest_start, attach_point_alignment,
587 aligned_heap_base_min_address, zerobased_max, size, alignment, page_size);
588 }
589
590 // Now we go for heaps with base != 0. We need a noaccess prefix to efficiently
591 // implement null checks.
592 noaccess_prefix = noaccess_prefix_size(alignment);
593
594 // Try to attach at addresses that are aligned to OopEncodingHeapMax. Disjointbase mode.
595 char** addresses = get_attach_addresses_for_disjoint_mode();
596 int i = 0;
597 while (addresses[i] && // End of array not yet reached.
598 ((_base == nullptr) || // No previous try succeeded.
599 (_base + size > (char *)OopEncodingHeapMax && // Not zerobased or unscaled address.
600 !CompressedOops::is_disjoint_heap_base_address((address)_base)))) { // Not disjoint address.
601 char* const attach_point = addresses[i];
602 assert(attach_point >= aligned_heap_base_min_address, "Flag support broken");
603 try_reserve_heap(size + noaccess_prefix, alignment, page_size, attach_point);
604 i++;
605 }
606
607 // Last, desperate try without any placement.
608 if (_base == nullptr) {
609 log_trace(gc, heap, coops)("Trying to allocate at address null heap of size " SIZE_FORMAT_X, size + noaccess_prefix);
610 initialize(size + noaccess_prefix, alignment, page_size, nullptr, false);
611 }
612 }
613 }
614
615 ReservedHeapSpace::ReservedHeapSpace(size_t size, size_t alignment, size_t page_size, const char* heap_allocation_directory) : ReservedSpace() {
616
617 if (size == 0) {
618 return;
619 }
620
621 if (heap_allocation_directory != nullptr) {
622 _fd_for_heap = os::create_file_for_heap(heap_allocation_directory);
623 if (_fd_for_heap == -1) {
624 vm_exit_during_initialization(
625 err_msg("Could not create file for Heap at location %s", heap_allocation_directory));
626 }
627 // When there is a backing file directory for this space then whether
628 // large pages are allocated is up to the filesystem of the backing file.
629 // If requested, let the user know that explicit large pages can't be used.
630 if (use_explicit_large_pages(page_size) && large_pages_requested()) {
631 log_debug(gc, heap)("Cannot allocate explicit large pages for Java Heap when AllocateHeapAt option is set.");
632 }
633 }
634
635 // Heap size should be aligned to alignment, too.
636 guarantee(is_aligned(size, alignment), "set by caller");
637
638 if (UseCompressedOops) {
639 initialize_compressed_heap(size, alignment, page_size);
640 if (_size > size) {
641 // We allocated heap with noaccess prefix.
642 // It can happen we get a zerobased/unscaled heap with noaccess prefix,
643 // if we had to try at arbitrary address.
644 establish_noaccess_prefix();
645 }
646 } else {
647 initialize(size, alignment, page_size, nullptr, false);
648 }
649
650 assert(markWord::encode_pointer_as_mark(_base).decode_pointer() == _base,
651 "area must be distinguishable from marks for mark-sweep");
652 assert(markWord::encode_pointer_as_mark(&_base[size]).decode_pointer() == &_base[size],
653 "area must be distinguishable from marks for mark-sweep");
654
655 if (base() != nullptr) {
656 MemTracker::record_virtual_memory_type((address)base(), mtJavaHeap);
657 }
658
659 if (_fd_for_heap != -1) {
660 ::close(_fd_for_heap);
661 }
662 }
663
664 MemRegion ReservedHeapSpace::region() const {
665 return MemRegion((HeapWord*)base(), (HeapWord*)end());
666 }
667
668 // Reserve space for code segment. Same as Java heap only we mark this as
669 // executable.
670 ReservedCodeSpace::ReservedCodeSpace(size_t r_size,
671 size_t rs_align,
672 size_t rs_page_size) : ReservedSpace() {
673 initialize(r_size, rs_align, rs_page_size, /*requested address*/ nullptr, /*executable*/ true);
674 MemTracker::record_virtual_memory_type((address)base(), mtCode);
675 }
676
677 // VirtualSpace
678
679 VirtualSpace::VirtualSpace() {
680 _low_boundary = nullptr;
681 _high_boundary = nullptr;
682 _low = nullptr;
683 _high = nullptr;
684 _lower_high = nullptr;
685 _middle_high = nullptr;
686 _upper_high = nullptr;
687 _lower_high_boundary = nullptr;
688 _middle_high_boundary = nullptr;
689 _upper_high_boundary = nullptr;
690 _lower_alignment = 0;
691 _middle_alignment = 0;
692 _upper_alignment = 0;
693 _special = false;
694 _executable = false;
695 }
696
697
698 bool VirtualSpace::initialize(ReservedSpace rs, size_t committed_size) {
699 const size_t max_commit_granularity = os::page_size_for_region_unaligned(rs.size(), 1);
700 return initialize_with_granularity(rs, committed_size, max_commit_granularity);
701 }
702
703 bool VirtualSpace::initialize_with_granularity(ReservedSpace rs, size_t committed_size, size_t max_commit_granularity) {
704 if(!rs.is_reserved()) return false; // allocation failed.
705 assert(_low_boundary == nullptr, "VirtualSpace already initialized");
706 assert(max_commit_granularity > 0, "Granularity must be non-zero.");
707
708 _low_boundary = rs.base();
709 _high_boundary = low_boundary() + rs.size();
710
711 _low = low_boundary();
712 _high = low();
713
714 _special = rs.special();
715 _executable = rs.executable();
716
717 // When a VirtualSpace begins life at a large size, make all future expansion
718 // and shrinking occur aligned to a granularity of large pages. This avoids
719 // fragmentation of physical addresses that inhibits the use of large pages
720 // by the OS virtual memory system. Empirically, we see that with a 4MB
721 // page size, the only spaces that get handled this way are codecache and
722 // the heap itself, both of which provide a substantial performance
723 // boost in many benchmarks when covered by large pages.
724 //
725 // No attempt is made to force large page alignment at the very top and
726 // bottom of the space if they are not aligned so already.
727 _lower_alignment = os::vm_page_size();
728 _middle_alignment = max_commit_granularity;
729 _upper_alignment = os::vm_page_size();
730
731 // End of each region
732 _lower_high_boundary = align_up(low_boundary(), middle_alignment());
733 _middle_high_boundary = align_down(high_boundary(), middle_alignment());
734 _upper_high_boundary = high_boundary();
735
736 // High address of each region
737 _lower_high = low_boundary();
738 _middle_high = lower_high_boundary();
739 _upper_high = middle_high_boundary();
740
741 // commit to initial size
742 if (committed_size > 0) {
743 if (!expand_by(committed_size)) {
744 return false;
745 }
746 }
747 return true;
748 }
749
750
751 VirtualSpace::~VirtualSpace() {
752 release();
753 }
754
755
756 void VirtualSpace::release() {
757 // This does not release memory it reserved.
758 // Caller must release via rs.release();
759 _low_boundary = nullptr;
760 _high_boundary = nullptr;
761 _low = nullptr;
762 _high = nullptr;
763 _lower_high = nullptr;
764 _middle_high = nullptr;
765 _upper_high = nullptr;
766 _lower_high_boundary = nullptr;
767 _middle_high_boundary = nullptr;
768 _upper_high_boundary = nullptr;
769 _lower_alignment = 0;
770 _middle_alignment = 0;
771 _upper_alignment = 0;
772 _special = false;
773 _executable = false;
774 }
775
776
777 size_t VirtualSpace::committed_size() const {
778 return pointer_delta(high(), low(), sizeof(char));
779 }
780
781
782 size_t VirtualSpace::reserved_size() const {
783 return pointer_delta(high_boundary(), low_boundary(), sizeof(char));
784 }
785
786
787 size_t VirtualSpace::uncommitted_size() const {
788 return reserved_size() - committed_size();
789 }
790
791 size_t VirtualSpace::actual_committed_size() const {
792 // Special VirtualSpaces commit all reserved space up front.
793 if (special()) {
794 return reserved_size();
795 }
796
797 size_t committed_low = pointer_delta(_lower_high, _low_boundary, sizeof(char));
798 size_t committed_middle = pointer_delta(_middle_high, _lower_high_boundary, sizeof(char));
799 size_t committed_high = pointer_delta(_upper_high, _middle_high_boundary, sizeof(char));
800
801 #ifdef ASSERT
802 size_t lower = pointer_delta(_lower_high_boundary, _low_boundary, sizeof(char));
803 size_t middle = pointer_delta(_middle_high_boundary, _lower_high_boundary, sizeof(char));
804 size_t upper = pointer_delta(_upper_high_boundary, _middle_high_boundary, sizeof(char));
805
806 if (committed_high > 0) {
807 assert(committed_low == lower, "Must be");
808 assert(committed_middle == middle, "Must be");
809 }
810
811 if (committed_middle > 0) {
812 assert(committed_low == lower, "Must be");
813 }
814 if (committed_middle < middle) {
815 assert(committed_high == 0, "Must be");
816 }
817
818 if (committed_low < lower) {
819 assert(committed_high == 0, "Must be");
820 assert(committed_middle == 0, "Must be");
821 }
822 #endif
823
824 return committed_low + committed_middle + committed_high;
825 }
826
827
828 bool VirtualSpace::contains(const void* p) const {
829 return low() <= (const char*) p && (const char*) p < high();
830 }
831
832 static void pretouch_expanded_memory(void* start, void* end) {
833 assert(is_aligned(start, os::vm_page_size()), "Unexpected alignment");
834 assert(is_aligned(end, os::vm_page_size()), "Unexpected alignment");
835
836 os::pretouch_memory(start, end);
837 }
838
839 static bool commit_expanded(char* start, size_t size, size_t alignment, bool pre_touch, bool executable) {
840 if (os::commit_memory(start, size, alignment, executable)) {
841 if (pre_touch || AlwaysPreTouch) {
842 pretouch_expanded_memory(start, start + size);
843 }
844 return true;
845 }
846
847 debug_only(warning(
848 "INFO: os::commit_memory(" PTR_FORMAT ", " PTR_FORMAT
849 " size=" SIZE_FORMAT ", executable=%d) failed",
850 p2i(start), p2i(start + size), size, executable);)
851
852 return false;
853 }
854
855 /*
856 First we need to determine if a particular virtual space is using large
857 pages. This is done at the initialize function and only virtual spaces
858 that are larger than LargePageSizeInBytes use large pages. Once we
859 have determined this, all expand_by and shrink_by calls must grow and
860 shrink by large page size chunks. If a particular request
861 is within the current large page, the call to commit and uncommit memory
862 can be ignored. In the case that the low and high boundaries of this
863 space is not large page aligned, the pages leading to the first large
864 page address and the pages after the last large page address must be
865 allocated with default pages.
866 */
867 bool VirtualSpace::expand_by(size_t bytes, bool pre_touch) {
868 if (uncommitted_size() < bytes) {
869 return false;
870 }
871
872 if (special()) {
873 // don't commit memory if the entire space is pinned in memory
874 _high += bytes;
875 return true;
876 }
877
878 char* previous_high = high();
879 char* unaligned_new_high = high() + bytes;
880 assert(unaligned_new_high <= high_boundary(), "cannot expand by more than upper boundary");
881
882 // Calculate where the new high for each of the regions should be. If
883 // the low_boundary() and high_boundary() are LargePageSizeInBytes aligned
884 // then the unaligned lower and upper new highs would be the
885 // lower_high() and upper_high() respectively.
886 char* unaligned_lower_new_high = MIN2(unaligned_new_high, lower_high_boundary());
887 char* unaligned_middle_new_high = MIN2(unaligned_new_high, middle_high_boundary());
888 char* unaligned_upper_new_high = MIN2(unaligned_new_high, upper_high_boundary());
889
890 // Align the new highs based on the regions alignment. lower and upper
891 // alignment will always be default page size. middle alignment will be
892 // LargePageSizeInBytes if the actual size of the virtual space is in
893 // fact larger than LargePageSizeInBytes.
894 char* aligned_lower_new_high = align_up(unaligned_lower_new_high, lower_alignment());
895 char* aligned_middle_new_high = align_up(unaligned_middle_new_high, middle_alignment());
896 char* aligned_upper_new_high = align_up(unaligned_upper_new_high, upper_alignment());
897
898 // Determine which regions need to grow in this expand_by call.
899 // If you are growing in the lower region, high() must be in that
900 // region so calculate the size based on high(). For the middle and
901 // upper regions, determine the starting point of growth based on the
902 // location of high(). By getting the MAX of the region's low address
903 // (or the previous region's high address) and high(), we can tell if it
904 // is an intra or inter region growth.
905 size_t lower_needs = 0;
906 if (aligned_lower_new_high > lower_high()) {
907 lower_needs = pointer_delta(aligned_lower_new_high, lower_high(), sizeof(char));
908 }
909 size_t middle_needs = 0;
910 if (aligned_middle_new_high > middle_high()) {
911 middle_needs = pointer_delta(aligned_middle_new_high, middle_high(), sizeof(char));
912 }
913 size_t upper_needs = 0;
914 if (aligned_upper_new_high > upper_high()) {
915 upper_needs = pointer_delta(aligned_upper_new_high, upper_high(), sizeof(char));
916 }
917
918 // Check contiguity.
919 assert(low_boundary() <= lower_high() && lower_high() <= lower_high_boundary(),
920 "high address must be contained within the region");
921 assert(lower_high_boundary() <= middle_high() && middle_high() <= middle_high_boundary(),
922 "high address must be contained within the region");
923 assert(middle_high_boundary() <= upper_high() && upper_high() <= upper_high_boundary(),
924 "high address must be contained within the region");
925
926 // Commit regions
927 if (lower_needs > 0) {
928 assert(lower_high() + lower_needs <= lower_high_boundary(), "must not expand beyond region");
929 if (!commit_expanded(lower_high(), lower_needs, _lower_alignment, pre_touch, _executable)) {
930 return false;
931 }
932 _lower_high += lower_needs;
933 }
934
935 if (middle_needs > 0) {
936 assert(middle_high() + middle_needs <= middle_high_boundary(), "must not expand beyond region");
937 if (!commit_expanded(middle_high(), middle_needs, _middle_alignment, pre_touch, _executable)) {
938 return false;
939 }
940 _middle_high += middle_needs;
941 }
942
943 if (upper_needs > 0) {
944 assert(upper_high() + upper_needs <= upper_high_boundary(), "must not expand beyond region");
945 if (!commit_expanded(upper_high(), upper_needs, _upper_alignment, pre_touch, _executable)) {
946 return false;
947 }
948 _upper_high += upper_needs;
949 }
950
951 _high += bytes;
952 return true;
953 }
954
955 // A page is uncommitted if the contents of the entire page is deemed unusable.
956 // Continue to decrement the high() pointer until it reaches a page boundary
957 // in which case that particular page can now be uncommitted.
958 void VirtualSpace::shrink_by(size_t size) {
959 if (committed_size() < size)
960 fatal("Cannot shrink virtual space to negative size");
961
962 if (special()) {
963 // don't uncommit if the entire space is pinned in memory
964 _high -= size;
965 return;
966 }
967
968 char* unaligned_new_high = high() - size;
969 assert(unaligned_new_high >= low_boundary(), "cannot shrink past lower boundary");
970
971 // Calculate new unaligned address
972 char* unaligned_upper_new_high =
973 MAX2(unaligned_new_high, middle_high_boundary());
974 char* unaligned_middle_new_high =
975 MAX2(unaligned_new_high, lower_high_boundary());
976 char* unaligned_lower_new_high =
977 MAX2(unaligned_new_high, low_boundary());
978
979 // Align address to region's alignment
980 char* aligned_upper_new_high = align_up(unaligned_upper_new_high, upper_alignment());
981 char* aligned_middle_new_high = align_up(unaligned_middle_new_high, middle_alignment());
982 char* aligned_lower_new_high = align_up(unaligned_lower_new_high, lower_alignment());
983
984 // Determine which regions need to shrink
985 size_t upper_needs = 0;
986 if (aligned_upper_new_high < upper_high()) {
987 upper_needs =
988 pointer_delta(upper_high(), aligned_upper_new_high, sizeof(char));
989 }
990 size_t middle_needs = 0;
991 if (aligned_middle_new_high < middle_high()) {
992 middle_needs =
993 pointer_delta(middle_high(), aligned_middle_new_high, sizeof(char));
994 }
995 size_t lower_needs = 0;
996 if (aligned_lower_new_high < lower_high()) {
997 lower_needs =
998 pointer_delta(lower_high(), aligned_lower_new_high, sizeof(char));
999 }
1000
1001 // Check contiguity.
1002 assert(middle_high_boundary() <= upper_high() &&
1003 upper_high() <= upper_high_boundary(),
1004 "high address must be contained within the region");
1005 assert(lower_high_boundary() <= middle_high() &&
1006 middle_high() <= middle_high_boundary(),
1007 "high address must be contained within the region");
1008 assert(low_boundary() <= lower_high() &&
1009 lower_high() <= lower_high_boundary(),
1010 "high address must be contained within the region");
1011
1012 // Uncommit
1013 if (upper_needs > 0) {
1014 assert(middle_high_boundary() <= aligned_upper_new_high &&
1015 aligned_upper_new_high + upper_needs <= upper_high_boundary(),
1016 "must not shrink beyond region");
1017 if (!os::uncommit_memory(aligned_upper_new_high, upper_needs, _executable)) {
1018 debug_only(warning("os::uncommit_memory failed"));
1019 return;
1020 } else {
1021 _upper_high -= upper_needs;
1022 }
1023 }
1024 if (middle_needs > 0) {
1025 assert(lower_high_boundary() <= aligned_middle_new_high &&
1026 aligned_middle_new_high + middle_needs <= middle_high_boundary(),
1027 "must not shrink beyond region");
1028 if (!os::uncommit_memory(aligned_middle_new_high, middle_needs, _executable)) {
1029 debug_only(warning("os::uncommit_memory failed"));
1030 return;
1031 } else {
1032 _middle_high -= middle_needs;
1033 }
1034 }
1035 if (lower_needs > 0) {
1036 assert(low_boundary() <= aligned_lower_new_high &&
1037 aligned_lower_new_high + lower_needs <= lower_high_boundary(),
1038 "must not shrink beyond region");
1039 if (!os::uncommit_memory(aligned_lower_new_high, lower_needs, _executable)) {
1040 debug_only(warning("os::uncommit_memory failed"));
1041 return;
1042 } else {
1043 _lower_high -= lower_needs;
1044 }
1045 }
1046
1047 _high -= size;
1048 }
1049
1050 #ifndef PRODUCT
1051 void VirtualSpace::check_for_contiguity() {
1052 // Check contiguity.
1053 assert(low_boundary() <= lower_high() &&
1054 lower_high() <= lower_high_boundary(),
1055 "high address must be contained within the region");
1056 assert(lower_high_boundary() <= middle_high() &&
1057 middle_high() <= middle_high_boundary(),
1058 "high address must be contained within the region");
1059 assert(middle_high_boundary() <= upper_high() &&
1060 upper_high() <= upper_high_boundary(),
1061 "high address must be contained within the region");
1062 assert(low() >= low_boundary(), "low");
1063 assert(low_boundary() <= lower_high_boundary(), "lower high boundary");
1064 assert(upper_high_boundary() <= high_boundary(), "upper high boundary");
1065 assert(high() <= upper_high(), "upper high");
1066 }
1067
1068 void VirtualSpace::print_on(outputStream* out) const {
1069 out->print ("Virtual space:");
1070 if (special()) out->print(" (pinned in memory)");
1071 out->cr();
1072 out->print_cr(" - committed: " SIZE_FORMAT, committed_size());
1073 out->print_cr(" - reserved: " SIZE_FORMAT, reserved_size());
1074 out->print_cr(" - [low, high]: [" PTR_FORMAT ", " PTR_FORMAT "]", p2i(low()), p2i(high()));
1075 out->print_cr(" - [low_b, high_b]: [" PTR_FORMAT ", " PTR_FORMAT "]", p2i(low_boundary()), p2i(high_boundary()));
1076 }
1077
1078 void VirtualSpace::print() const {
1079 print_on(tty);
1080 }
1081
1082 #endif