Remove offer_nice_chunk(), PL_nice_chunk and PL_nice_chunk_size.

These provided a non-public API for the hash and array code to donate free
memory direct to the SV head allocation routines, instead of returning it
to the malloc system with free().

I assume that on some older mallocs this could offer significant benefits.
However, my benchmarking on a modern malloc couldn't detect any significant
effect (positive or negative) on removing the code. Its (continued) presence,
however, has downsides

a: slightly more code complexity
b: slightly larger interpreter structure
c: in the steady state, if net creation of SVs is zero, 1 chunk of allocated
   but unused memory will exist (per thread)

So I think it best to remove it.

1 files changed, 1 insertions, 5 deletions

diff --git a/av.c b/av.c
index 86aaae0195..b061828a7f 100644
--- a/av.c
+++ b/av.c
@@ -150,11 +150,7 @@ Perl_av_extend(pTHX_ AV *av, I32 key)
 		assert(newmax >= AvMAX(av));
 		Newx(ary, newmax+1, SV*);
 		Copy(AvALLOC(av), ary, AvMAX(av)+1, SV*);
-		if (AvMAX(av) > 64)
-		    offer_nice_chunk(AvALLOC(av),
-				     (AvMAX(av)+1) * sizeof(const SV *));
-		else
-		    Safefree(AvALLOC(av));
+		Safefree(AvALLOC(av));
 		AvALLOC(av) = ary;
 #endif
 #ifdef Perl_safesysmalloc_size