Re: thread stacks and strict vm overcommit accounting

[Andrew Morton]

On Thu, 15 Mar 2007 23:33:43 +0000
Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote:

> > Stack RSS should certainly be included in Committed_AS,
> > but RLIMIT_STACK merely limits how big the stack vma may grow to:
> > at any moment the stack vma is probably very much smaller,
> > and only its current size is accounted in Committed_AS.
> 
> With a typical size as a fuzz factor preaccounted in later kernels.

Where's that done?

> > > > Is this the intended behaviour?
> > > 
> > > That sounds like a bug to me.
> > 
> > I'm suspecting it's an oddity rather than a bug.
> 
> It is intended behaviour.

Each instance of

main()
{
	sleep(100);
}

appears to increase Committed_AS by around 200kb.  But we've committed to
providing it with 8MB for stack.

How come this is correct?

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