> I don't understand the point concerning trimming/fragmentation/threading by
> Charles-Francois: dlmalloc will allocate its own memory segment using mmap
> and handle memory inside that segment when you do a
> dlmalloc/dlfree/dlrealloc. Other malloc implementations will work in their
> own separate space and so won't impact or be impacted by what happens in
> dlmalloc segments.

Most of the allocations come from the heap - through sbrk - which is a
shared resource, and is a contiguous space. mmap is only used for big
allocations.

>
> dlmalloc is not that much different from pymalloc in that regard: it handles
> its own memory pool on top of the system memory implementations.
> Yet you can have an application that uses the ordinary malloc while calling
> some Python code which uses pymalloc without any
> trimming/fragmentation/threading issues.

It's completely different. Pymalloc is used *on top* of libc's malloc,
while dlmalloc would be be used in parallel.