[Issue 17881] Provide mechanism to preallocate memory from the GC

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=17881

--- Comment #12 from Rainer Schuetze <r.sagitario at gmx.de> ---
The current GC already does something in that regard as it pre-assigns a new
memory page to a free-list of elements of the size of the last request.

The GC locking overhead can be reduced by helping the inliner a bit with some
assembly. I have tried that for Win64 recently and the benchmarks showed an
improvement of about 5%.

--