Re: [PATCH, RFD]: Unbreak no-mmu mmap

Mike Frysinger
2007-06-11T23:22:16Z

On 6/11/07, Bernd Schmidt <bernds_cb1@t-online.de> wrote:
> Mike Frysinger wrote:
> > On 6/9/07, Matt Mackall <mpm@selenic.com> wrote:
> >> On Fri, Jun 08, 2007 at 03:53:49PM +0200, Bernd Schmidt wrote:
> >> > 2. It is no longer possible to get blocks smaller than a page through
> >> > mmap. This behaviour was used by simplemalloc, which is an insane
> >> > way of implementing malloc on nommu systems and hopefully not used
> >> > by anyone anymore.
> >>
> >> That's worrisome. Breaking existing apps/libraries seems like a bad
> >> idea.
> >
> > it isnt breaking anything ... simplemalloc() will continue to execute
> > in newer kernels
>
> While that's true, it'll have an even bigger memory overhead than it
> already does (simplemalloc, by trapping into the kernel and creating
> vm_area/vm_list structures for every malloc call, has huge overheads in
> both time and space).

yes, it does increase the runtime overhead, but the simplemalloc
implementation is already tagged as crappy, so i dont think it's that
big of a deal ... especially in light of all of the advantages the
other malloc implementation gets us nommu peeps
-mike