1 /*
2 * Copyright (c) 2019, 2026, 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 "cds/aotCompressedPointers.hpp"
26 #include "cds/aotLogging.hpp"
27 #include "cds/aotMetaspace.hpp"
28 #include "cds/archiveBuilder.hpp"
29 #include "cds/archiveUtils.hpp"
30 #include "cds/cdsConfig.hpp"
31 #include "cds/classListParser.hpp"
32 #include "cds/classListWriter.hpp"
33 #include "cds/dynamicArchive.hpp"
34 #include "cds/filemap.hpp"
35 #include "cds/heapShared.hpp"
36 #include "cds/lambdaProxyClassDictionary.hpp"
37 #include "classfile/classLoader.hpp"
38 #include "classfile/systemDictionaryShared.hpp"
39 #include "classfile/vmClasses.hpp"
40 #include "interpreter/bootstrapInfo.hpp"
41 #include "memory/metaspaceUtils.hpp"
42 #include "memory/resourceArea.hpp"
43 #include "oops/compressedOops.inline.hpp"
44 #include "oops/klass.inline.hpp"
45 #include "runtime/arguments.hpp"
46 #include "utilities/bitMap.inline.hpp"
47 #include "utilities/debug.hpp"
48 #include "utilities/formatBuffer.hpp"
49 #include "utilities/globalDefinitions.hpp"
50 #include "utilities/spinYield.hpp"
51
52 CHeapBitMap* ArchivePtrMarker::_ptrmap = nullptr;
53 CHeapBitMap* ArchivePtrMarker::_rw_ptrmap = nullptr;
54 CHeapBitMap* ArchivePtrMarker::_ro_ptrmap = nullptr;
55 CHeapBitMap* ArchivePtrMarker::_ac_ptrmap = nullptr;
56 VirtualSpace* ArchivePtrMarker::_vs;
57
58 bool ArchivePtrMarker::_compacted;
59
60 void ArchivePtrMarker::initialize(CHeapBitMap* ptrmap, VirtualSpace* vs) {
61 assert(_ptrmap == nullptr, "initialize only once");
62 assert(_rw_ptrmap == nullptr, "initialize only once");
63 assert(_ro_ptrmap == nullptr, "initialize only once");
64 assert(_ac_ptrmap == nullptr, "initialize only once");
65 _vs = vs;
66 _compacted = false;
67 _ptrmap = ptrmap;
68
69 // Use this as initial guesstimate. We should need less space in the
70 // archive, but if we're wrong the bitmap will be expanded automatically.
71 size_t estimated_archive_size = MetaspaceGC::capacity_until_GC();
72 // But set it smaller in debug builds so we always test the expansion code.
73 // (Default archive is about 12MB).
74 DEBUG_ONLY(estimated_archive_size = 6 * M);
75
76 // We need one bit per pointer in the archive.
77 _ptrmap->initialize(estimated_archive_size / sizeof(intptr_t));
78 }
79
80 void ArchivePtrMarker::initialize_rw_ro_ac_maps(CHeapBitMap* rw_ptrmap, CHeapBitMap* ro_ptrmap, CHeapBitMap* ac_ptrmap) {
81 address* buff_bottom = (address*)ArchiveBuilder::current()->buffer_bottom();
82 address* rw_bottom = (address*)ArchiveBuilder::current()->rw_region()->base();
83 address* ro_bottom = (address*)ArchiveBuilder::current()->ro_region()->base();
84 address* ac_bottom = (address*)ArchiveBuilder::current()->ac_region()->base();
85
86 // The bit in _ptrmap that cover the very first word in the rw/ro/ac regions.
87 size_t rw_start = rw_bottom - buff_bottom;
88 size_t ro_start = ro_bottom - buff_bottom;
89 size_t ac_start = ac_bottom - buff_bottom;
90
91 // The number of bits used by the rw/ro ptrmaps. We might have lots of zero
92 // bits at the bottom and top of rw/ro ptrmaps, but these zeros will be
93 // removed by FileMapInfo::write_bitmap_region().
94 size_t rw_size = ArchiveBuilder::current()->rw_region()->used() / sizeof(address);
95 size_t ro_size = ArchiveBuilder::current()->ro_region()->used() / sizeof(address);
96 size_t ac_size = ArchiveBuilder::current()->ac_region()->used() / sizeof(address);
97
98 // The last (exclusive) bit in _ptrmap that covers the rw/ro regions.
99 // Note: _ptrmap is dynamically expanded only when an actual pointer is written, so
100 // it may not be as large as we want.
101 size_t rw_end = MIN2<size_t>(rw_start + rw_size, _ptrmap->size());
102 size_t ro_end = MIN2<size_t>(ro_start + ro_size, _ptrmap->size());
103 size_t ac_end = MIN2<size_t>(ac_start + ac_size, _ptrmap->size());
104
105 rw_ptrmap->initialize(rw_size);
106 ro_ptrmap->initialize(ro_size);
107 ac_ptrmap->initialize(ac_size);
108
109 for (size_t rw_bit = rw_start; rw_bit < rw_end; rw_bit++) {
110 rw_ptrmap->at_put(rw_bit - rw_start, _ptrmap->at(rw_bit));
111 }
112
113 for(size_t ro_bit = ro_start; ro_bit < ro_end; ro_bit++) {
114 ro_ptrmap->at_put(ro_bit - ro_start, _ptrmap->at(ro_bit));
115 }
116
117 for (size_t ac_bit = ac_start; ac_bit < ac_end; ac_bit++) {
118 ac_ptrmap->at_put(ac_bit - ac_start, _ptrmap->at(ac_bit));
119 }
120
121 _rw_ptrmap = rw_ptrmap;
122 _ro_ptrmap = ro_ptrmap;
123 _ac_ptrmap = ac_ptrmap;
124 }
125
126 void ArchivePtrMarker::mark_pointer(address* ptr_loc) {
127 assert(_ptrmap != nullptr, "not initialized");
128 assert(!_compacted, "cannot mark anymore");
129
130 if (ptr_base() <= ptr_loc && ptr_loc < ptr_end()) {
131 address value = *ptr_loc;
132 // We don't want any pointer that points to very bottom of the archive, otherwise when
133 // AOTMetaspace::default_base_address()==0, we can't distinguish between a pointer
134 // to nothing (null) vs a pointer to an objects that happens to be at the very bottom
135 // of the archive.
136 assert(value != (address)ptr_base(), "don't point to the bottom of the archive");
137
138 if (value != nullptr) {
139 assert(uintx(ptr_loc) % sizeof(intptr_t) == 0, "pointers must be stored in aligned addresses");
140 size_t idx = ptr_loc - ptr_base();
141 if (_ptrmap->size() <= idx) {
142 _ptrmap->resize((idx + 1) * 2);
143 }
144 assert(idx < _ptrmap->size(), "must be");
145 _ptrmap->set_bit(idx);
146 //tty->print_cr("Marking pointer [" PTR_FORMAT "] -> " PTR_FORMAT " @ %5zu", p2i(ptr_loc), p2i(*ptr_loc), idx);
147 }
148 }
149 }
150
151 void ArchivePtrMarker::clear_pointer(address* ptr_loc) {
152 assert(_ptrmap != nullptr, "not initialized");
153 assert(!_compacted, "cannot clear anymore");
154
155 assert(ptr_base() <= ptr_loc && ptr_loc < ptr_end(), "must be");
156 assert(uintx(ptr_loc) % sizeof(intptr_t) == 0, "pointers must be stored in aligned addresses");
157 size_t idx = ptr_loc - ptr_base();
158 assert(idx < _ptrmap->size(), "cannot clear pointers that have not been marked");
159 _ptrmap->clear_bit(idx);
160 //tty->print_cr("Clearing pointer [" PTR_FORMAT "] -> " PTR_FORMAT " @ %5zu", p2i(ptr_loc), p2i(*ptr_loc), idx);
161 }
162
163 class ArchivePtrBitmapCleaner: public BitMapClosure {
164 CHeapBitMap* _ptrmap;
165 address* _ptr_base;
166 address _relocatable_base;
167 address _relocatable_end;
168 size_t _max_non_null_offset;
169
170 public:
171 ArchivePtrBitmapCleaner(CHeapBitMap* ptrmap, address* ptr_base, address relocatable_base, address relocatable_end) :
172 _ptrmap(ptrmap), _ptr_base(ptr_base),
173 _relocatable_base(relocatable_base), _relocatable_end(relocatable_end), _max_non_null_offset(0) {}
174
175 bool do_bit(size_t offset) {
176 address* ptr_loc = _ptr_base + offset;
177 address ptr_value = *ptr_loc;
178 if (ptr_value != nullptr) {
179 assert(_relocatable_base <= ptr_value && ptr_value < _relocatable_end, "do not point to arbitrary locations!");
180 if (_max_non_null_offset < offset) {
181 _max_non_null_offset = offset;
182 }
183 } else {
184 _ptrmap->clear_bit(offset);
185 DEBUG_ONLY(log_trace(aot, reloc)("Clearing pointer [" PTR_FORMAT "] -> null @ %9zu", p2i(ptr_loc), offset));
186 }
187
188 return true;
189 }
190
191 size_t max_non_null_offset() const { return _max_non_null_offset; }
192 };
193
194 void ArchivePtrMarker::compact(address relocatable_base, address relocatable_end) {
195 assert(!_compacted, "cannot compact again");
196 ArchivePtrBitmapCleaner cleaner(_ptrmap, ptr_base(), relocatable_base, relocatable_end);
197 _ptrmap->iterate(&cleaner);
198 compact(cleaner.max_non_null_offset());
199 }
200
201 void ArchivePtrMarker::compact(size_t max_non_null_offset) {
202 assert(!_compacted, "cannot compact again");
203 _ptrmap->resize(max_non_null_offset + 1);
204 _compacted = true;
205 }
206
207 char* DumpRegion::expand_top_to(char* newtop) {
208 assert(is_allocatable(), "must be initialized and not packed");
209 assert(newtop >= _top, "must not grow backwards");
210 if (newtop > _end) {
211 ArchiveBuilder::current()->report_out_of_space(_name, newtop - _top);
212 ShouldNotReachHere();
213 }
214
215 commit_to(newtop);
216 _top = newtop;
217
218 if (ArchiveBuilder::is_active() && ArchiveBuilder::current()->is_in_buffer_space(_base)) {
219 uintx delta = ArchiveBuilder::current()->buffer_to_offset((address)(newtop-1));
220 if (delta > AOTCompressedPointers::MaxMetadataOffsetBytes) {
221 // This is just a sanity check and should not appear in any real world usage. This
222 // happens only if you allocate more than 2GB of shared objects and would require
223 // millions of shared classes.
224 aot_log_error(aot)("Out of memory in the %s: Please reduce the number of shared classes.", CDSConfig::type_of_archive_being_written());
225 AOTMetaspace::unrecoverable_writing_error();
226 }
227 }
228
229 return _top;
230 }
231
232 void DumpRegion::commit_to(char* newtop) {
233 assert(CDSConfig::is_dumping_archive(), "sanity");
234 char* base = _rs->base();
235 size_t need_committed_size = newtop - base;
236 size_t has_committed_size = _vs->committed_size();
237 if (need_committed_size < has_committed_size) {
238 return;
239 }
240
241 size_t min_bytes = need_committed_size - has_committed_size;
242 size_t preferred_bytes = 1 * M;
243 size_t uncommitted = _vs->reserved_size() - has_committed_size;
244
245 size_t commit = MAX2(min_bytes, preferred_bytes);
246 commit = MIN2(commit, uncommitted);
247 assert(commit <= uncommitted, "sanity");
248
249 if (!_vs->expand_by(commit, false)) {
250 aot_log_error(aot)("Failed to expand shared space to %zu bytes",
251 need_committed_size);
252 AOTMetaspace::unrecoverable_writing_error();
253 }
254
255 const char* which;
256 if (_rs->base() == (char*)AOTMetaspace::symbol_rs_base()) {
257 which = "symbol";
258 } else {
259 which = "shared";
260 }
261 log_debug(aot)("Expanding %s spaces by %7zu bytes [total %9zu bytes ending at %p]",
262 which, commit, _vs->actual_committed_size(), _vs->high());
263 }
264
265 char* DumpRegion::allocate(size_t num_bytes, size_t alignment) {
266 // Always align to at least minimum alignment
267 alignment = MAX2(SharedSpaceObjectAlignment, alignment);
268 char* p = (char*)align_up(_top, alignment);
269 char* newtop = p + align_up(num_bytes, (size_t)SharedSpaceObjectAlignment);
270 expand_top_to(newtop);
271 memset(p, 0, newtop - p);
272 return p;
273 }
274
275 void DumpRegion::append_intptr_t(intptr_t n, bool need_to_mark) {
276 assert(is_aligned(_top, sizeof(intptr_t)), "bad alignment");
277 intptr_t *p = (intptr_t*)_top;
278 char* newtop = _top + sizeof(intptr_t);
279 expand_top_to(newtop);
280 *p = n;
281 if (need_to_mark) {
282 ArchivePtrMarker::mark_pointer(p);
283 }
284 }
285
286 void DumpRegion::print(size_t total_bytes) const {
287 char* base = used() > 0 ? ArchiveBuilder::current()->to_requested(_base) : nullptr;
288 log_debug(aot)("%s space: %9zu [ %4.1f%% of total] out of %9zu bytes [%5.1f%% used] at " INTPTR_FORMAT,
289 _name, used(), percent_of(used(), total_bytes), reserved(), percent_of(used(), reserved()),
290 p2i(base));
291 }
292
293 void DumpRegion::print_out_of_space_msg(const char* failing_region, size_t needed_bytes) {
294 aot_log_error(aot)("[%-8s] " PTR_FORMAT " - " PTR_FORMAT " capacity =%9d, allocated =%9d",
295 _name, p2i(_base), p2i(_top), int(_end - _base), int(_top - _base));
296 if (strcmp(_name, failing_region) == 0) {
297 aot_log_error(aot)(" required = %d", int(needed_bytes));
298 }
299 }
300
301 void DumpRegion::init(ReservedSpace* rs, VirtualSpace* vs) {
302 _rs = rs;
303 _vs = vs;
304 // Start with 0 committed bytes. The memory will be committed as needed.
305 if (!_vs->initialize(*_rs, 0)) {
306 fatal("Unable to allocate memory for shared space");
307 }
308 _base = _top = _rs->base();
309 _end = _rs->end();
310 }
311
312 void DumpRegion::pack(DumpRegion* next) {
313 if (!is_packed()) {
314 _end = (char*)align_up(_top, AOTMetaspace::core_region_alignment());
315 _is_packed = true;
316 }
317 if (next != nullptr) {
318 next->_rs = _rs;
319 next->_vs = _vs;
320 next->_base = next->_top = this->_end;
321 next->_end = _rs->end();
322 }
323 }
324
325 void WriteClosure::do_ptr(void** p) {
326 // Write ptr into the archive; ptr can be:
327 // (a) null -> written as 0
328 // (b) a "buffered" address -> written as is
329 // (c) a "source" address -> convert to "buffered" and write
330 // The common case is (c). E.g., when writing the vmClasses into the archive.
331 // We have (b) only when we don't have a corresponding source object. E.g.,
332 // the archived c++ vtable entries.
333 address ptr = *(address*)p;
334 if (ptr != nullptr && !ArchiveBuilder::current()->is_in_buffer_space(ptr)) {
335 ptr = ArchiveBuilder::current()->get_buffered_addr(ptr);
336 }
337 // null pointers do not need to be converted to offsets
338 if (ptr != nullptr) {
339 ptr = (address)ArchiveBuilder::current()->buffer_to_offset(ptr);
340 }
341 _dump_region->append_intptr_t((intptr_t)ptr, false);
342 }
343
344 void ReadClosure::do_ptr(void** p) {
345 assert(*p == nullptr, "initializing previous initialized pointer.");
346 u4 narrowp = checked_cast<u4>(nextPtr());
347 *p = AOTCompressedPointers::decode<void*>(cast_from_u4(narrowp), _base_address);
348 }
349
350 void ReadClosure::do_u4(u4* p) {
351 intptr_t obj = nextPtr();
352 *p = (u4)(uintx(obj));
353 }
354
355 void ReadClosure::do_int(int* p) {
356 intptr_t obj = nextPtr();
357 *p = (int)(intx(obj));
358 }
359
360 void ReadClosure::do_bool(bool* p) {
361 intptr_t obj = nextPtr();
362 *p = (bool)(uintx(obj));
363 }
364
365 void ReadClosure::do_tag(int tag) {
366 int old_tag;
367 old_tag = (int)(intptr_t)nextPtr();
368 // do_int(&old_tag);
369 assert(tag == old_tag, "tag doesn't match (%d, expected %d)", old_tag, tag);
370 FileMapInfo::assert_mark(tag == old_tag);
371 }
372
373 void ArchiveUtils::log_to_classlist(BootstrapInfo* bootstrap_specifier, TRAPS) {
374 if (ClassListWriter::is_enabled()) {
375 if (LambdaProxyClassDictionary::is_supported_invokedynamic(bootstrap_specifier)) {
376 const constantPoolHandle& pool = bootstrap_specifier->pool();
377 if (SystemDictionaryShared::is_builtin_loader(pool->pool_holder()->class_loader_data())) {
378 // Currently lambda proxy classes are supported only for the built-in loaders.
379 ResourceMark rm(THREAD);
380 int pool_index = bootstrap_specifier->bss_index();
381 ClassListWriter w;
382 w.stream()->print("%s %s", ClassListParser::lambda_proxy_tag(), pool->pool_holder()->name()->as_C_string());
383 CDSIndyInfo cii;
384 ClassListParser::populate_cds_indy_info(pool, pool_index, &cii, CHECK);
385 GrowableArray<const char*>* indy_items = cii.items();
386 for (int i = 0; i < indy_items->length(); i++) {
387 w.stream()->print(" %s", indy_items->at(i));
388 }
389 w.stream()->cr();
390 }
391 }
392 }
393 }
394
395
396 // "boot", "platform", "app" or nullptr
397 const char* ArchiveUtils::builtin_loader_name_or_null(oop loader) {
398 if (loader == nullptr) {
399 return "boot";
400 } else if (loader == SystemDictionary::java_platform_loader()) {
401 return "platform";
402 } else if (loader == SystemDictionary::java_system_loader()) {
403 return "app";
404 } else {
405 return nullptr;
406 }
407 }
408
409 // "boot", "platform", "app". Asserts if not a built-in-loader
410 const char* ArchiveUtils::builtin_loader_name(oop loader) {
411 const char* name = builtin_loader_name_or_null(loader);
412 assert(name != nullptr, "must be a built-in loader");
413 return name;
414 }
415
416 bool ArchiveUtils::builtin_loader_from_type(const char* loader_type, oop* value_ret) {
417 if (strcmp(loader_type, "boot") == 0) {
418 *value_ret = nullptr;
419 return true;
420 } else if (strcmp(loader_type, "platform") == 0) {
421 *value_ret = SystemDictionary::java_platform_loader();
422 return true;
423 } else if (strcmp(loader_type, "app") == 0) {
424 *value_ret = SystemDictionary::java_system_loader();
425 return true;
426 } else {
427 DEBUG_ONLY(*value_ret = cast_to_oop((void*)badOopVal));
428 return false;
429 }
430 }
431
432 oop ArchiveUtils::builtin_loader_from_type(int loader_type) {
433 if (loader_type == ClassLoader::BOOT_LOADER) {
434 return nullptr;
435 } else if (loader_type == ClassLoader::PLATFORM_LOADER) {
436 return SystemDictionary::java_platform_loader();
437 } else if (loader_type == ClassLoader::APP_LOADER) {
438 return SystemDictionary::java_system_loader();
439 } else {
440 ShouldNotReachHere();
441 return nullptr;
442 }
443 }
444
445 bool ArchiveUtils::has_aot_initialized_mirror(InstanceKlass* src_ik) {
446 if (!ArchiveBuilder::current()->has_been_archived(src_ik)) {
447 return false;
448 }
449 return ArchiveBuilder::current()->get_buffered_addr(src_ik)->has_aot_initialized_mirror();
450 }
451
452 size_t HeapRootSegments::size_in_bytes(size_t seg_idx) {
453 assert(seg_idx < _count, "In range");
454 return objArrayOopDesc::object_size(size_in_elems(seg_idx)) * HeapWordSize;
455 }
456
457 int HeapRootSegments::size_in_elems(size_t seg_idx) {
458 assert(seg_idx < _count, "In range");
459 if (seg_idx != _count - 1) {
460 return _max_size_in_elems;
461 } else {
462 // Last slice, leftover
463 return _roots_count % _max_size_in_elems;
464 }
465 }
466
467 size_t HeapRootSegments::segment_offset(size_t seg_idx) {
468 assert(seg_idx < _count, "In range");
469 return _base_offset + seg_idx * _max_size_in_bytes;
470 }
471
472 ArchiveWorkers::ArchiveWorkers() :
473 _end_semaphore(0),
474 _num_workers(max_workers()),
475 _started_workers(0),
476 _finish_tokens(0),
477 _state(UNUSED),
478 _task(nullptr) {}
479
480 ArchiveWorkers::~ArchiveWorkers() {
481 assert(AtomicAccess::load(&_state) != WORKING, "Should not be working");
482 }
483
484 int ArchiveWorkers::max_workers() {
485 // The pool is used for short-lived bursty tasks. We do not want to spend
486 // too much time creating and waking up threads unnecessarily. Plus, we do
487 // not want to overwhelm large machines. This is why we want to be very
488 // conservative about the number of workers actually needed.
489 return MAX2(0, log2i_graceful(os::active_processor_count()));
490 }
491
492 bool ArchiveWorkers::is_parallel() {
493 return _num_workers > 0;
494 }
495
496 void ArchiveWorkers::start_worker_if_needed() {
497 while (true) {
498 int cur = AtomicAccess::load(&_started_workers);
499 if (cur >= _num_workers) {
500 return;
501 }
502 if (AtomicAccess::cmpxchg(&_started_workers, cur, cur + 1, memory_order_relaxed) == cur) {
503 new ArchiveWorkerThread(this);
504 return;
505 }
506 }
507 }
508
509 void ArchiveWorkers::run_task(ArchiveWorkerTask* task) {
510 assert(AtomicAccess::load(&_state) == UNUSED, "Should be unused yet");
511 assert(AtomicAccess::load(&_task) == nullptr, "Should not have running tasks");
512 AtomicAccess::store(&_state, WORKING);
513
514 if (is_parallel()) {
515 run_task_multi(task);
516 } else {
517 run_task_single(task);
518 }
519
520 assert(AtomicAccess::load(&_state) == WORKING, "Should be working");
521 AtomicAccess::store(&_state, SHUTDOWN);
522 }
523
524 void ArchiveWorkers::run_task_single(ArchiveWorkerTask* task) {
525 // Single thread needs no chunking.
526 task->configure_max_chunks(1);
527
528 // Execute the task ourselves, as there are no workers.
529 task->work(0, 1);
530 }
531
532 void ArchiveWorkers::run_task_multi(ArchiveWorkerTask* task) {
533 // Multiple threads can work with multiple chunks.
534 task->configure_max_chunks(_num_workers * CHUNKS_PER_WORKER);
535
536 // Set up the run and publish the task. Issue one additional finish token
537 // to cover the semaphore shutdown path, see below.
538 AtomicAccess::store(&_finish_tokens, _num_workers + 1);
539 AtomicAccess::release_store(&_task, task);
540
541 // Kick off pool startup by starting a single worker, and proceed
542 // immediately to executing the task locally.
543 start_worker_if_needed();
544
545 // Execute the task ourselves, while workers are catching up.
546 // This allows us to hide parts of task handoff latency.
547 task->run();
548
549 // Done executing task locally, wait for any remaining workers to complete.
550 // Once all workers report, we can proceed to termination. To do this safely,
551 // we need to make sure every worker has left. A spin-wait alone would suffice,
552 // but we do not want to burn cycles on it. A semaphore alone would not be safe,
553 // since workers can still be inside it as we proceed from wait here. So we block
554 // on semaphore first, and then spin-wait for all workers to terminate.
555 _end_semaphore.wait();
556 SpinYield spin;
557 while (AtomicAccess::load(&_finish_tokens) != 0) {
558 spin.wait();
559 }
560
561 OrderAccess::fence();
562
563 assert(AtomicAccess::load(&_finish_tokens) == 0, "All tokens are consumed");
564 }
565
566 void ArchiveWorkers::run_as_worker() {
567 assert(is_parallel(), "Should be in parallel mode");
568
569 ArchiveWorkerTask* task = AtomicAccess::load_acquire(&_task);
570 task->run();
571
572 // All work done in threads should be visible to caller.
573 OrderAccess::fence();
574
575 // Signal the pool the work is complete, and we are exiting.
576 // Worker cannot do anything else with the pool after this.
577 if (AtomicAccess::sub(&_finish_tokens, 1, memory_order_relaxed) == 1) {
578 // Last worker leaving. Notify the pool it can unblock to spin-wait.
579 // Then consume the last token and leave.
580 _end_semaphore.signal();
581 int last = AtomicAccess::sub(&_finish_tokens, 1, memory_order_relaxed);
582 assert(last == 0, "Should be");
583 }
584 }
585
586 void ArchiveWorkerTask::run() {
587 while (true) {
588 int chunk = AtomicAccess::load(&_chunk);
589 if (chunk >= _max_chunks) {
590 return;
591 }
592 if (AtomicAccess::cmpxchg(&_chunk, chunk, chunk + 1, memory_order_relaxed) == chunk) {
593 assert(0 <= chunk && chunk < _max_chunks, "Sanity");
594 work(chunk, _max_chunks);
595 }
596 }
597 }
598
599 void ArchiveWorkerTask::configure_max_chunks(int max_chunks) {
600 if (_max_chunks == 0) {
601 _max_chunks = max_chunks;
602 }
603 }
604
605 ArchiveWorkerThread::ArchiveWorkerThread(ArchiveWorkers* pool) : NamedThread(), _pool(pool) {
606 set_name("ArchiveWorkerThread");
607 if (os::create_thread(this, os::os_thread)) {
608 os::start_thread(this);
609 } else {
610 vm_exit_during_initialization("Unable to create archive worker",
611 os::native_thread_creation_failed_msg());
612 }
613 }
614
615 void ArchiveWorkerThread::run() {
616 // Avalanche startup: each worker starts two others.
617 _pool->start_worker_if_needed();
618 _pool->start_worker_if_needed();
619
620 // Set ourselves up.
621 os::set_priority(this, NearMaxPriority);
622
623 // Work.
624 _pool->run_as_worker();
625 }
626
627 void ArchiveWorkerThread::post_run() {
628 this->NamedThread::post_run();
629 delete this;
630 }