SuperPages utilization survey

[Konstantin Belousov]

On Sat, Jun 09, 2012 at 10:31:17AM +0300, Mikolaj Golub wrote:
> 
> On Fri, 1 Jun 2012 14:54:48 +0200 Ivan Voras wrote:
> 
>  IV> On 1 June 2012 14:35, Wojciech Puchar <wojtek at wojtek.tensor.gdynia.pl> wrote:
>  >>> http://people.freebsd.org/~ivoras/stuff/spsurvey.py
> 
>  ...
> 
>  IV> If anyone posts more data, I'll analyse it. I'm more worried about the
>  IV> granularity of procstat, where it marks the entire region if a single
>  IV> superpage exists in it - it means any such analysis is only
>  IV> approximate.
> 
> Here is a patch (for kernel and procstat) that allows to see amount of pages
> mapped to superpages.
> 
> http://people.freebsd.org/~trociny/procstat-superpages.cnt.1.patch
> 
> Not sure it is useful enough to be committed.

Superpage aggregates mappings for several normal-sized pages.
As a consequence, when you iterate over small pages in
sysctl_kern_proc_vmmap(), you account each superpage as many time as
much constituent small pages it contains.
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