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Re: PATCH: new GC implementation
On Wed, Sep 22, 1999 at 10:44:47PM +0200, Andi Kleen wrote:
> I could imagine that it would be a maintenance nightmare though:
>
> If it was hardcoded there might be the problem that the compiler will
> stop working on a future OS version with changed memory map.
There's an easy portable way to find a huge contiguous hunk of vma.
You mmap a gigantic hunk of anonymous memory, then get rid of it.
It's kind of a shame unix doesn't have a reserve-vm-area syscall,
but (if necessary) the same effect can be had by leaving that huge
area mapped with PROT_NONE. It probably won't be necessary though;
I'll have to think about a good solution here...
> > ... for targets with 128-bit types -- ia32 will soon be one of
> > those, in fact.
>
> For long double ?
For SSE.
> Sorry I was wrong. I would keep the MAP_ANONYMOUS bit for now,
> until /dev/zero is fixed to not use zeromap_page_range anymore.
We should certainly use MAP_ANONYMOUS when it's available.
r~