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8379435: More proposed cleanups for JDK-8373595 A new ObjectMonitorTable implementation

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Reviewed-by: coleenp, fbredberg
This commit is contained in:
Daniel D. Daugherty 2026-03-11 16:37:46 +00:00
parent ef55947162
commit 775f07e671
1 changed files with 10 additions and 10 deletions
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20
src/hotspot/share/runtime/objectMonitorTable.cpp
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@ -69,7 +69,7 @@
// allocate a new table (twice as large as the old one), and then copy all the
// old monitor pointers from the old table to the new.
//
// But since the OMT is a concurrent hash table and things needs to work for
// But since the OMT is a concurrent hash table and things need to work for
// other clients of the OMT while we grow it, it gets a bit more
// complicated.
//
@ -125,7 +125,7 @@ class ObjectMonitorTable::Table : public CHeapObj<mtObjectMonitor> {
DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, 0);
const size_t _capacity_mask; // One less than its power-of-two capacity
Atomic<Table*> _prev; // Set while rehashing
Atomic<Table*> _prev; // Set while growing/rebuilding
Atomic<Entry>* _buckets; // The payload
DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, sizeof(_capacity_mask) + sizeof(_prev) + sizeof(_buckets));
Atomic<size_t> _items_count;
@ -251,8 +251,8 @@ public:
assert(index != start_index, "invariant");
}
// Rehashing could have started by now, but if a monitor has been inserted in a
// newer table, it was inserted after the get linearization point.
// Rebuilding could have started by now, but if a monitor has been inserted
// in a newer table, it was inserted after the get linearization point.
return nullptr;
}
@ -278,7 +278,7 @@ public:
// To avoid concurrent inserts succeeding, place a tombstone here.
Entry result = bucket.compare_exchange(entry, tombstone(), memory_order_relaxed);
if (result == entry) {
// Success! Nobody will try to insert here again, except reinsert from rehashing.
// Success! Nobody will try to insert here again, except reinsert from rebuilding.
return nullptr;
}
entry = result;
@ -333,11 +333,11 @@ public:
dec_items_count();
entry = result;
} else {
// Out of allowance; leaving place for rehashing to succeed.
// Out of allowance; leave space for rebuilding to succeed.
// To avoid concurrent inserts succeeding, place a tombstone here.
Entry result = bucket.compare_exchange(entry, tombstone(), memory_order_acq_rel);
if (result == entry) {
// Success; nobody will try to insert here again, except reinsert from rehashing.
// Success; nobody will try to insert here again, except reinsert from rebuilding.
return nullptr;
}
entry = result;
@ -558,7 +558,7 @@ ObjectMonitorTable::Table* ObjectMonitorTable::grow_table(Table* curr) {
}
}
// Somebody else started rehashing; restart in new table.
// Somebody else started rebuilding; restart in their new table.
delete new_table;
return result;
@ -591,7 +591,7 @@ void ObjectMonitorTable::remove_monitor_entry(ObjectMonitor* monitor) {
assert(monitor_get(obj) != monitor, "should have been removed");
}
// Before handshake; rehash and unlink tables.
// Before handshake; rebuild and unlink tables.
void ObjectMonitorTable::rebuild(GrowableArray<Table*>* delete_list) {
Table* new_table;
{
@ -629,7 +629,7 @@ void ObjectMonitorTable::rebuild(GrowableArray<Table*>* delete_list) {
new_table = new Table(new_capacity, curr);
Table* result = _curr.compare_exchange(curr, new_table, memory_order_acq_rel);
if (result != curr) {
// Somebody else racingly started rehashing. Delete the
// Somebody else racingly started rebuilding. Delete the
// new_table and treat somebody else's table as the new one.
delete new_table;
new_table = result;