RFR: 8242082: Shenandoah: Purge Traversal mode

[Aleksey Shipilev]

On 4/3/20 12:36 PM, Aleksey Shipilev wrote:
> On 4/3/20 12:16 PM, Roman Kennke wrote:
>> Traversal mode has become cumbersome to maintain. Every single
>> non-trivial feature required extra work to play with Traversal, and
>> usually caused a trail of follow-up issues. And all that for little
>> gain. We are transplanting the interesting properties to the upcoming
>> I-U mode (which is much less trouble-some), and can ditch Traversal mode
>> altogether.
>>
>> My original plan was to ditch it after I-U is in, but now I want to do a
>> couple of cleanups before I-U and I'm not in the mood to special-case
>> Traversal there. Let's get rid of it ahead of time.
>>
>> Issue:
>> https://bugs.openjdk.java.net/browse/JDK-8242082
>> Webrev:
>> http://cr.openjdk.java.net/~rkennke/JDK-8242082/webrev.00/
> 
> Good riddance.

Oh, and since you are purging seqnums from SHR, you might as well purge this:

 225   // Global allocation counter, increased for each allocation under Shenandoah heap lock.
 226   // Padded to avoid false sharing with the read-only fields above.
 227   struct PaddedAllocSeqNum {
 228     shenandoah_padding(0);
 229     uint64_t value;
 230     shenandoah_padding(1);
 231
 232     PaddedAllocSeqNum() {
 233       // start with 1, reserve 0 for uninitialized value
 234       value = 1;
 235     }
 236   };
 237
 238   static PaddedAllocSeqNum _alloc_seq_num;

...or leave it to me for the followup.

-- 
Thanks,
-Aleksey