Re: [PATCH] flexmmap: optimise mmap_base gap for hard limited stack

From: Arjan van de Ven
Date: Fri Sep 17 2004 - 08:24:46 EST


On Fri, Sep 17, 2004 at 03:18:30PM +0200, Utz Lehmann wrote:
> Ulrich Drepper [drepper@xxxxxxxxxx] wrote:
> > > A check for CAP_SYS_RESOURCE can be added. But i dont think it's worth.
> >
> > It is needed. Otherwise how do you allow increasing the stack size
> > again once it has been limited? I've no problem with using the smallest
> > reserved stack region with !CAP_SYS_RESOURCE, but otherwise the existing
> > method should be used.
>
> I made that change. The following patch only reduce the gap when the
> application can not extend the stack space anyway (hard limited stack &&
> !CAP_SYS_RESOURCE). All other cases stay unchanged except for the 1 MB hole
> for soft limited stacks >128 MB.
>
> It gave a nice way for making most of the default 128 MB gap usable for
> applications. Just run them with a hard stack limit.
>
> Now i can allocate more than 3.8GiB in one chunk on x86 (this patch +
> exec-shield + 4g/4g + ulimit -H -s 8192).

Ack; nice work!

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