Re: operator new no longer routes through rtl_AllocMemory in libsalcpprt under gbuild link rules

On 05/18/2012 04:23 PM, Michael Stahl wrote:
> checking "a massive allocation" doesn't really tell us all that much,
> because allocators typically operate in 2 modes:
> - for large objects, directly request zero-backed memory via mmap
> - for small objects, maintain elaborate data structures to allocate
> these from arenas or whatever

I had hoped to address this in the test code in my other post with 
100,000 times allocating 10,000 bytes each.  However, further inspection 
reveals that allocation is apparently brk-based there, so that it can 
only ever shrink memory back to the highest allocation that has not yet 
been freed.  (That is, changing the second, deleting, loop in my test 
code to run short one item prevents any shrinkage.)  Contrast that with 
the always-mmap approach of rtl/alloc.h, which allows for different 
shrinkage patterns.  (Whether or not that is relevant in practice.)

Stephan