1. Command-line:

```
java -XX:+UseShenandoahGC -XX:ShenandoahGCMode=generational -XX:+UnlockExperimentalVMOptions -XX:+UnlockDiagnosticVMOptions -XX:SuppressErrorAt=/shenandoahGeneration.cpp:997 -XX:SuppressErrorAt=/shenandoahVerifier.cpp:414 -XX:SuppressErrorAt=/shenandoahVerifier.cpp:408 -Xmx8g -Xms8g -XX:-ShenandoahUncommit -XX:-ShenandoahPacing -XX:-TieredCompilation -Xlog:async -Xlog:gc*=info -jar ./target/HyperAlloc-1.0.jar -d 120 -p 10 -r 50 -a 3072 -s 1536 -t 4 -b heapothesys.csv.allocation -l heapothesys.csv
```

2. Brief gdb session:

```
(gdb) thread 25
[Switching to thread 25 (Thread 0x7fd3781f3700 (LWP 45669))]
#0 0x00007fd3d34e4c2b in nanosleep () from /lib64/libc.so.6
(gdb) bt
#0 0x00007fd3d34e4c2b in nanosleep () from /lib64/libc.so.6
#1 0x00007fd3d34e4b4a in sleep () from /lib64/libc.so.6
#2 0x00007fd3d1d97d60 in os::message_box (title=0x7fd3d287ff63 "Unexpected Error",
    message=0x7fd3d341bee0 <VMError::report_and_die(int, char const*, char const*, __va_list_tag*, Thread*, unsigned char*, void*, void*, char const*, int, unsigned long)::buffer> "Internal Error at shenandoahFreeSet.cpp:276, pid=45268, tid=45669\nassert(usable_free == 0) failed: usable_free is a multiple of card_size and card_size > min_fill_size\n\nDo you want to debug the proble"...)
    at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/os/posix/os_posix.cpp:1968
#3 0x00007fd3d1d8da7e in os::start_debugging (
    buf=0x7fd3d341bee0 <VMError::report_and_die(int, char const*, char const*, __va_list_tag*, Thread*, unsigned char*, void*, void*, char const*, int, unsigned long)::buffer> "Internal Error at shenandoahFreeSet.cpp:276, pid=45268, tid=45669\nassert(usable_free == 0) failed: usable_free is a multiple of card_size and card_size > min_fill_size\n\nDo you want to debug the proble"..., buflen=2000)
    at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/os/linux/os_linux.cpp:5199
#4 0x00007fd3d215cecd in VMError::show_message_box (
    buf=0x7fd3d341bee0 <VMError::report_and_die(int, char const*, char const*, __va_list_tag*, Thread*, unsigned char*, void*, void*, char const*, int, unsigned long)::buffer> "Internal Error at shenandoahFreeSet.cpp:276, pid=45268, tid=45669\nassert(usable_free == 0) failed: usable_free is a multiple of card_size and card_size > min_fill_size\n\nDo you want to debug the proble"..., buflen=2000)
    at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/utilities/vmError.cpp:1747
#5 0x00007fd3d215c03d in VMError::report_and_die (id=-536870912, message=0x7fd3d295be60 "assert(usable_free == 0) failed", detail_fmt=0x7fd3d295be18 "usable_free is a multiple of card_size and card_size > min_fill_size",
    detail_args=0x7fd3781f1da8, thread=0x7fd3b8001b80, pc=0x0, siginfo=0x0, context=0x7fd3d33c7720 <g_stored_assertion_context>,
    filename=0x7fd3d295bb20 "/home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahFreeSet.cpp", lineno=276, size=0)
    at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/utilities/vmError.cpp:1432
#6 0x00007fd3d215bd65 in VMError::report_and_die (thread=0x7fd3b8001b80, context=0x7fd3d33c7720 <g_stored_assertion_context>,
    filename=0x7fd3d295bb20 "/home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahFreeSet.cpp", lineno=276, message=0x7fd3d295be60 "assert(usable_free == 0) failed",
    detail_fmt=0x7fd3d295be18 "usable_free is a multiple of card_size and card_size > min_fill_size", detail_args=0x7fd3781f1da8) at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/utilities/vmError.cpp:1351
#7 0x00007fd3d15b9405 in report_vm_error (file=0x7fd3d295bb20 "/home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahFreeSet.cpp", line=276,
    error_msg=0x7fd3d295be60 "assert(usable_free == 0) failed", detail_fmt=0x7fd3d295be18 "usable_free is a multiple of card_size and card_size > min_fill_size")
    at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/utilities/debug.cpp:286
#8 0x00007fd3d1ed17e5 in ShenandoahFreeSet::try_allocate_in (this=0x7fd3cc137d90, r=0x7fd3d009dd80, req=..., in_new_region=@0x7fd3781f2157: false)
    at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahFreeSet.cpp:276
#9 0x00007fd3d1ed0f62 in ShenandoahFreeSet::allocate_with_old_affiliation (this=0x7fd3cc137d90, req=..., in_new_region=@0x7fd3781f2157: false)
    at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahFreeSet.cpp:85
#10 0x00007fd3d1ed120d in ShenandoahFreeSet::allocate_single (this=0x7fd3cc137d90, req=..., in_new_region=@0x7fd3781f2157: false)
    at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahFreeSet.cpp:179
#11 0x00007fd3d1ed3cde in ShenandoahFreeSet::allocate (this=0x7fd3cc137d90, req=..., in_new_region=@0x7fd3781f2157: false) at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahFreeSet.cpp:828
#12 0x00007fd3d1ef065d in ShenandoahHeap::allocate_memory_under_lock (this=0x7fd3cc0d46c0, req=..., in_new_region=@0x7fd3781f2157: false, is_promotion=false)
    at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp:1294
#13 0x00007fd3d1ef00c1 in ShenandoahHeap::allocate_memory (this=0x7fd3cc0d46c0, req=..., is_promotion=false) at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp:1185
#14 0x00007fd3d1eefe7b in ShenandoahHeap::allocate_new_plab (this=0x7fd3cc0d46c0, min_size=258, word_size=4160, actual_size=0x7fd3781f2240)
    at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp:1137
#15 0x00007fd3d1eef801 in ShenandoahHeap::allocate_from_plab_slow (this=0x7fd3cc0d46c0, thread=0x7fd3b8001b80, size=94, is_promotion=true)
    at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp:975
#16 0x00007fd3d0fd01bf in ShenandoahHeap::allocate_from_plab (this=0x7fd3cc0d46c0, thread=0x7fd3b8001b80, size=94, is_promotion=true)
    at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahHeap.inline.hpp:317
#17 0x00007fd3d0fd05f6 in ShenandoahHeap::try_evacuate_object (this=0x7fd3cc0d46c0, p=0x639a48e20, thread=0x7fd3b8001b80, from_region=0x7fd3d009a300, target_gen=OLD_GENERATION)
    at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahHeap.inline.hpp:402
#18 0x00007fd3d0fd0426 in ShenandoahHeap::evacuate_object (this=0x7fd3cc0d46c0, p=0x639a48e20, thread=0x7fd3b8001b80) at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahHeap.inline.hpp:357
#19 0x00007fd3d1ef8547 in ShenandoahConcurrentEvacuateRegionObjectClosure::do_object (this=0x7fd3781f2d50, p=0x639a48e20) at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp:1444
#20 0x00007fd3d1efc015 in ShenandoahHeap::marked_object_iterate<ShenandoahConcurrentEvacuateRegionObjectClosure> (this=0x7fd3cc0d46c0, region=0x7fd3d009a300, cl=0x7fd3781f2d50, limit=0x639bfff48)
    at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahHeap.inline.hpp:871
#21 0x00007fd3d1efa5e7 in ShenandoahHeap::marked_object_iterate<ShenandoahConcurrentEvacuateRegionObjectClosure> (this=0x7fd3cc0d46c0, region=0x7fd3d009a300, cl=0x7fd3781f2d50)
    at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahHeap.inline.hpp:814
#22 0x00007fd3d1ef8a7e in ShenandoahGenerationalEvacuationTask::do_work (this=0x7fd3c11bb6d0) at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp:1537
#23 0x00007fd3d1ef8859 in ShenandoahGenerationalEvacuationTask::work (this=0x7fd3c11bb6d0, worker_id=1) at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp:1518
#24 0x00007fd3d21ed2e8 in WorkerTaskDispatcher::worker_run_task (this=0x7fd3cc128ad8) at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shared/workerThread.cpp:69
#25 0x00007fd3d21ed7aa in WorkerThread::run (this=0x7fd3b8001b80) at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shared/workerThread.cpp:164
#26 0x00007fd3d20bdcf8 in Thread::call_run (this=0x7fd3b8001b80) at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/runtime/thread.cpp:224
#27 0x00007fd3d1d83777 in thread_native_entry (thread=0x7fd3b8001b80) at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/os/linux/os_linux.cpp:739
#28 0x00007fd3d39dd44b in start_thread () from /lib64/libpthread.so.0
#29 0x00007fd3d351452f in clone () from /lib64/libc.so.6
(gdb) frame 7
#7 0x00007fd3d15b9405 in report_vm_error (file=0x7fd3d295bb20 "/home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahFreeSet.cpp", line=276,
    error_msg=0x7fd3d295be60 "assert(usable_free == 0) failed", detail_fmt=0x7fd3d295be18 "usable_free is a multiple of card_size and card_size > min_fill_size")
    at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/utilities/debug.cpp:286
286 VMError::report_and_die(Thread::current_or_null(), context, file, line, error_msg, detail_fmt, detail_args);
(gdb) up
#8 0x00007fd3d1ed17e5 in ShenandoahFreeSet::try_allocate_in (this=0x7fd3cc137d90, r=0x7fd3d009dd80, req=..., in_new_region=@0x7fd3781f2157: false)
    at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahFreeSet.cpp:276
276 assert(usable_free == 0, "usable_free is a multiple of card_size and card_size > min_fill_size");
(gdb) list 250,290
250 assert(ctx->is_bitmap_clear_range(ctx->top_bitmap(r), r->end()), "Bitmap above top_bitmap() must be clear");
251
252 // Leave top_bitmap alone. The first time a heap region is put into service, top_bitmap should equal end.
253 // Thereafter, it should represent the upper bound on parts of the bitmap that need to be cleared.
254 log_debug(gc)("NOT clearing bitmap for region " SIZE_FORMAT ", top_bitmap: "
255 PTR_FORMAT " at transition from FREE to %s",
256 r->index(), p2i(ctx->top_bitmap(r)), affiliation_name(req.affiliation()));
257 } else if (r->affiliation() != req.affiliation()) {
258 return NULL;
259 }
260
261 in_new_region = r->is_empty();
262 HeapWord* result = NULL;
263 size_t size = req.size();
264
265 // req.size() is in words, r->free() is in bytes.
266 if (ShenandoahElasticTLAB && req.is_lab_alloc()) {
267 if (req.type() == ShenandoahAllocRequest::_alloc_plab) {
268 // Need to assure that plabs are aligned on multiple of card region.
269 size_t free = r->free();
270 size_t usable_free = (free / CardTable::card_size()) << CardTable::card_shift();
271 if ((free != usable_free) && (free - usable_free < ShenandoahHeap::min_fill_size() * HeapWordSize)) {
272 // We'll have to add another card's memory to the padding
273 if (usable_free > CardTable::card_size()) {
274 usable_free -= CardTable::card_size();
275 } else {
276 assert(usable_free == 0, "usable_free is a multiple of card_size and card_size > min_fill_size");
277 }
278 }
279 free /= HeapWordSize;
280 usable_free /= HeapWordSize;
281 size_t remnant = size % CardTable::card_size_in_words();
282 if (remnant > 0) {
283 // Since we have Elastic TLABs, align size up. This is consistent with aligning min_size up.
284 size = size - remnant + CardTable::card_size_in_words();
285 }
286 if (size > usable_free) {
287 size = usable_free;
288 assert(size % CardTable::card_size_in_words() == 0, "usable_free is a multiple of card table size");
289 }
290
(gdb) set print pretty on
(gdb) print req
$1 = (ShenandoahAllocRequest &) @0x7fd3781f21e0: {
  <StackObj> = {<No data fields>},
  members of ShenandoahAllocRequest:
  _min_size = 258,
  _requested_size = 4160,
  _actual_size = 0,
  _alloc_type = ShenandoahAllocRequest::_alloc_plab,
  _affiliation = OLD_GENERATION,
  _actual_size_set = false
}
(gdb) print free
$2 = 520
(gdb) print usable_free
$3 = 512
(gdb) print free - usable_free
$4 = 8
(gdb) print ShenandoahHeap::min_fill_size() * HeapWordSize
$5 = 16
(gdb) print CardTable::card_size()
$6 = 512
(gdb) up
#9 0x00007fd3d1ed0f62 in ShenandoahFreeSet::allocate_with_old_affiliation (this=0x7fd3cc137d90, req=..., in_new_region=@0x7fd3781f2157: false)
    at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahFreeSet.cpp:85
85 HeapWord* result = try_allocate_in(r, req, in_new_region);
(gdb) print req
$7 = (ShenandoahAllocRequest &) @0x7fd3781f21e0: {
  <StackObj> = {<No data fields>},
  members of ShenandoahAllocRequest:
  _min_size = 258,
  _requested_size = 4160,
  _actual_size = 0,
  _alloc_type = ShenandoahAllocRequest::_alloc_plab,
  _affiliation = OLD_GENERATION,
  _actual_size_set = false
}
(gdb) up
#10 0x00007fd3d1ed120d in ShenandoahFreeSet::allocate_single (this=0x7fd3cc137d90, req=..., in_new_region=@0x7fd3781f2157: false)
    at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahFreeSet.cpp:179
179 result = allocate_with_old_affiliation(req, in_new_region);
(gdb) up
#11 0x00007fd3d1ed3cde in ShenandoahFreeSet::allocate (this=0x7fd3cc137d90, req=..., in_new_region=@0x7fd3781f2157: false) at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahFreeSet.cpp:828
828 return allocate_single(req, in_new_region);
(gdb) print in_new_region
$8 = (bool &) @0x7fd3781f2157: false
(gdb) up
#12 0x00007fd3d1ef065d in ShenandoahHeap::allocate_memory_under_lock (this=0x7fd3cc0d46c0, req=..., in_new_region=@0x7fd3781f2157: false, is_promotion=false)
    at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp:1294
1294 result = (allow_allocation)? _free_set->allocate(req, in_new_region): nullptr;
(gdb) up
#13 0x00007fd3d1ef00c1 in ShenandoahHeap::allocate_memory (this=0x7fd3cc0d46c0, req=..., is_promotion=false) at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp:1185
1185 result = allocate_memory_under_lock(req, in_new_region, is_promotion);
(gdb) print req
$9 = (ShenandoahAllocRequest &) @0x7fd3781f21e0: {
  <StackObj> = {<No data fields>},
  members of ShenandoahAllocRequest:
  _min_size = 258,
  _requested_size = 4160,
  _actual_size = 0,
  _alloc_type = ShenandoahAllocRequest::_alloc_plab,
  _affiliation = OLD_GENERATION,
  _actual_size_set = false
}
(gdb) up
#14 0x00007fd3d1eefe7b in ShenandoahHeap::allocate_new_plab (this=0x7fd3cc0d46c0, min_size=258, word_size=4160, actual_size=0x7fd3781f2240)
    at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp:1137
1137 HeapWord* res = allocate_memory(req, false);
(gdb) up
#15 0x00007fd3d1eef801 in ShenandoahHeap::allocate_from_plab_slow (this=0x7fd3cc0d46c0, thread=0x7fd3b8001b80, size=94, is_promotion=true)
    at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp:975
975 HeapWord* plab_buf = allocate_new_plab(min_size, cur_size, &actual_size);
(gdb) print cur_size
$10 = 4160
(gdb) print min_size
$11 = 258
(gdb) up
#16 0x00007fd3d0fd01bf in ShenandoahHeap::allocate_from_plab (this=0x7fd3cc0d46c0, thread=0x7fd3b8001b80, size=94, is_promotion=true)
    at /home/ysr/workplace/ysr/genshen-ysr/shenandoah/src/hotspot/share/gc/shenandoah/shenandoahHeap.inline.hpp:317
317 obj = allocate_from_plab_slow(thread, size, is_promotion);
(gdb) print size
$12 = 94
```
3. Excerpt from GC log prior to error:

```
[105.806s][info][gc,ergo ] GC(34) Adaptive CSet Selection for YOUNG. Max Evacuation: 163M, Actual Free: 45055K.
[105.807s][info][gc,ergo ] GC(34) Collectable Garbage: 148M (99%), Immediate: 45055K (29%), CSet: 104M (70%)
[105.807s][info][gc,ergo ] GC(34) Evacuation Targets: YOUNG: 27893K, PROMOTE: 69523K, OLD: 0B, TOTAL: 97416K
[105.807s][info][gc,ergo ] GC(34) Old available: 276M is partitioned into old evacuation budget: 0B, aged region promotion budget: 135M, regular region promotion budget: 55786K, loaned for young evacuation: 0B, loaned for young allocations: 86016K, excess: 2495K
[105.807s][info][gc,ergo ] GC(34) After generational memory budget adjustments, old available: 1556M, young_available: 6636M
[105.807s][info][gc ] GC(34) Pause Final Mark (YOUNG) 2.720ms
[105.807s][info][gc,start ] GC(34) Concurrent thread roots
[105.807s][info][gc,task ] GC(34) Using 10 of 20 workers for Concurrent thread roots
[105.808s][info][gc,ergo ] Failed to shrink TLAB or GCLAB request (4104) in region 171 to 70 because min_size() is 256
[105.808s][info][gc,ergo ] Failed to shrink TLAB or GCLAB request (4104) in region 172 to 76 because min_size() is 256
[105.808s][info][gc,ergo ] Failed to shrink TLAB or GCLAB request (4104) in region 190 to 45 because min_size() is 256
[105.808s][info][gc,ergo ] Failed to shrink TLAB or GCLAB request (4104) in region 191 to 1 because min_size() is 256
[105.808s][info][gc,ergo ] Failed to shrink TLAB or GCLAB request (4104) in region 192 to 23 because min_size() is 256
[105.808s][info][gc,ergo ] Failed to shrink TLAB or GCLAB request (4104) in region 193 to 21 because min_size() is 256
[105.808s][info][gc,ergo ] Failed to shrink TLAB or GCLAB request (4104) in region 194 to 38 because min_size() is 256
[105.808s][info][gc,ergo ] Failed to shrink TLAB or GCLAB request (4104) in region 195 to 109 because min_size() is 256
[105.808s][info][gc,ergo ] Failed to shrink TLAB or GCLAB request (4104) in region 196 to 29 because min_size() is 256
[105.808s][info][gc,ergo ] Failed to shrink TLAB or GCLAB request (4104) in region 197 to 30 because min_size() is 256
[105.808s][info][gc,ergo ] Failed to shrink TLAB or GCLAB request (4104) in region 198 to 77 because min_size() is 256
[105.808s][info][gc,ergo ] Failed to shrink TLAB or GCLAB request (4104) in region 199 to 57 because min_size() is 256
[105.808s][info][gc,ergo ] Failed to shrink TLAB or GCLAB request (4104) in region 200 to 19 because min_size() is 256
[105.808s][info][gc,ergo ] Failed to shrink TLAB or GCLAB request (4104) in region 201 to 17 because min_size() is 256
[105.808s][info][gc,ergo ] Failed to shrink TLAB or GCLAB request (4104) in region 202 to 9 because min_size() is 256
[105.808s][info][gc,ergo ] Failed to shrink TLAB or GCLAB request (4104) in region 203 to 93 because min_size() is 256
[105.808s][info][gc,ergo ] Failed to shrink TLAB or GCLAB request (4104) in region 204 to 25 because min_size() is 256
[105.808s][info][gc,ergo ] Failed to shrink TLAB or GCLAB request (4104) in region 209 to 21 because min_size() is 256
[105.808s][info][gc,ergo ] Failed to shrink TLAB or GCLAB request (4104) in region 210 to 51 because min_size() is 256
[105.808s][info][gc,ergo ] Failed to shrink TLAB or GCLAB request (4104) in region 211 to 23 because min_size() is 256
[105.808s][info][gc,ergo ] Failed to shrink TLAB or GCLAB request (4104) in region 212 to 9 because min_size() is 256
[105.808s][info][gc,ergo ] Failed to shrink TLAB or GCLAB request (4104) in region 213 to 18 because min_size() is 256
[105.808s][info][gc,ergo ] Failed to shrink TLAB or GCLAB request (4104) in region 323 to 1 because min_size() is 256
[105.809s][info][gc ] GC(34) Concurrent thread roots 1.845ms
[105.809s][info][gc,start ] GC(34) Concurrent weak references
[105.809s][info][gc,task ] GC(34) Using 10 of 20 workers for concurrent weak references
[105.809s][info][gc,ref ] GC(34) Encountered references: Soft: 1, Weak: 8, Final: 0, Phantom: 1
[105.809s][info][gc,ref ] GC(34) Discovered references: Soft: 0, Weak: 0, Final: 0, Phantom: 0
[105.809s][info][gc,ref ] GC(34) Enqueued references: Soft: 0, Weak: 0, Final: 0, Phantom: 0
[105.809s][info][gc ] GC(34) Concurrent weak references 0.131ms
[105.809s][info][gc,start ] GC(34) Concurrent weak roots
[105.809s][info][gc,task ] GC(34) Using 10 of 20 workers for concurrent weak root
[105.811s][info][gc ] GC(34) Concurrent weak roots 2.541ms
[105.811s][info][gc,start ] GC(34) Concurrent cleanup
[105.830s][info][gc ] GC(34) Concurrent cleanup 2867M->2831M(8192M) 18.798ms
[105.831s][info][gc,ergo ] GC(34) Free: 5032M, Max: 4096K regular, 4412M humongous, Frag: 12% external, 20% internal; Reserve: 327M, Max: 4096K
[105.831s][info][gc,start ] GC(34) Concurrent strong roots
[105.831s][info][gc,task ] GC(34) Using 10 of 20 workers for concurrent strong root
[105.831s][info][gc ] GC(34) Concurrent strong roots 0.542ms
[105.831s][info][gc,start ] GC(34) Concurrent evacuation
[105.831s][info][gc,task ] GC(34) Using 10 of 20 workers for concurrent evacuation
[105.849s][info][gc,ergo ] GC(34) Failed to shrink TLAB or GCLAB request (4128) in region 2046 to 32 because min_size() is 258
# To suppress the following error report, specify this argument
# after -XX: or in .hotspotrc: SuppressErrorAt=/shenandoahFreeSet.cpp:276
==============================================================================
Unexpected Error
------------------------------------------------------------------------------
Internal Error at shenandoahFreeSet.cpp:276, pid=45268, tid=45669
assert(usable_free == 0) failed: usable_free is a multiple of card_size and card_size > min_fill_size
```
3. This might or might not be related to the assertions that were suppressed in the linked ticket JDK-8301288.