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

From: Mike Frysinger
Date: Mon Jun 11 2007 - 19:22:18 EST


On 6/11/07, Bernd Schmidt <bernds_cb1@xxxxxxxxxxx> wrote:
Mike Frysinger wrote:
> On 6/9/07, Matt Mackall <mpm@xxxxxxxxxxx> 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
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