RFR(S) 8212127: Cleanup TLAB fast refill statistics, perf counters and etc.

[Aleksey Shipilev]

On 2/6/19 3:34 PM, zgu at redhat.com wrote:
>> *) In src/hotspot/share/gc/shared/threadLocalAllocBuffer.hpp, why
>> this whole thing is removed? I
>> would expect "just" the rename of slow_refill_waste() to
>> refill_waste() and removing
>> fast_refill_waste() here, leaving everything else untouched.
>>
>>  105   // statistics
>>  106
>>  107   int number_of_refills() const { return _number_of_refills; }
>>  108   int fast_refill_waste() const { return _fast_refill_waste; }
>>  109   int slow_refill_waste() const { return _slow_refill_waste; }
>>  110   int gc_waste() const          { return _gc_waste; }
>>  111   int slow_allocations() const  { return _slow_allocations; }
>>  112
> 
> They are dead code. Do they worth for another cleanup RFE for the
> trivial cleanup?

Okay. I thought the patch was about fast refills only. But indeed, we can clean these unused
definitions in the same patch. On one hand, removing trivial unused getters would require us to add
them back when they are needed. On the other hand, it seems that TLAB does every statistic
internally, and we should instead force callers to use higher-level TLAB methods to access and
interpret them.

Code looks good! I think we still need Serviceability to acknowledge this is okay to do.

-Aleksey