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SubjectRe: pageable page tables
On Tue, 25 Nov 1997, Ralf Baechle wrote:

> On Tue, Nov 25, 1997 at 09:37:00PM +0100, Rik van Riel wrote:
>
> > Another concern is that users can grab _all_ of system memory
> > by having several processes do a 2GB mmap of /dev/zero...
> > This 'doesn't take any memory' so they can take up as much
> > (non-pageable) pagetable memory as they want.
> > In fact, this is the main reason people asked me if I could look
> > into this... This is one of the biggest denial-of-service holes
> > still left. (ssstt)
>
> So the resource accounting should count those pages also.

Yes! This was one of the strange ideas I had to get used to with OpenVMS,
but it's also a big win for system management. A file's header(s) get(s)
charged against your disk quota just like the data blocks; your page
table pages get charged against your VM quota; etc.

Mark H. Wood, Lead System Programmer MWOOD@INDYVAX.IUPUI.EDU
Those who will not learn from history are doomed to reimplement it.


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