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