RFR: 8191786: Thread-SMR hash table size should be dynamic [v2]

[Coleen Phillimore]

On Tue, 25 May 2021 20:39:56 GMT, Daniel D. Daugherty <dcubed at openjdk.org> wrote:

>> Small change to switch Thread-SMR's hash table from ResourceHashtable to KVHashtable
>> so that a variable sized hash table is used instead of a fixed size hash table (1031 elements).
>> Also refactor common hash table size calculation code into static hash_table_size()
>> function and call it from both places.
>> 
>> Test with Mach5 Tier[1-7] testing.
>
> Daniel D. Daugherty has updated the pull request incrementally with one additional commit since the last revision:
> 
>   rehn CR

Changes requested by coleenp (Reviewer).

src/hotspot/share/runtime/threadSMR.cpp line 205:

> 203: 
> 204:   ~ThreadScanHashtable() {
> 205:       log_trace(thread, smr)("tid=" UINTX_FORMAT ": deallocate ThreadScanHashtable(%d) at " INTPTR_FORMAT, os::current_thread_id(), _table_size, p2i(this));

For a CHeap hashtable, I believe this should do this (or have KVHash have an API to delete all the entries).
Dictionary::~Dictionary() {
  DictionaryEntry* probe = NULL;
  for (int index = 0; index < table_size(); index++) {
    for (DictionaryEntry** p = bucket_addr(index); *p != NULL; ) {
      probe = *p;
      *p = probe->next();
      free_entry(probe);
    }
  }
  assert(number_of_entries() == 0, "should have removed all entries");
}

-------------

PR: https://git.openjdk.java.net/jdk/pull/4168