D array expansion and non-deterministic re-allocation

[Walter Bright]

Sean Kelly wrote:
> Denis Koroskin Wrote:
> 
>> Walter Bright Wrote:
>> 
>>> Denis Koroskin wrote:
>>>> It is *non*-deterministic. The decision to reallocate depends
>>>> (or will depend) on LRU and it may be cleared by another thread
>>>> (e.g. another thread may reset it manually or via a GC cycle
>>>> run).
>>> The LRU is thread local.
>> It will then prevent a moving GC from being possible in D.
>> 
>> Otherwise, moving a block of data will invalidate LRU which will
>> result in non-deterministic reallocation.
> 
> It won't work with the existing GC either.  If a page is completely
> emptied then it can be re-used for different sized allocations.  This
> is why the current cache is wiped during a collection.

In both cases, the LRU can be adjusted rather than wiped to account for it.