[Tfug] Locking from user-land

Tom Rini trini at kernel.crashing.org
Mon Jan 12 13:07:03 MST 2009


On Mon, Jan 12, 2009 at 11:44:33AM -0800, Bexley Hall wrote:
> Hi, Tom,
> 
> --- On Sun, 1/11/09, Tom Rini <trini at kernel.crashing.org> wrote:
> 
> > > Is there any way I can *effectively* wire down (even for
> > > a short -- but *guaranteed* -- period of time) a small
> > > amount of physical memory from user-land?
> > 
> > Sure, and I think this all even works on x86.  mem=(real
> > minus what you want), the top "what you want" is yours to do
> > with as you please.
> 
> But, that just "hides" it from the kernel (and, requires me to
> build a new kernel -- if so, I could just move what I wanted
> to do *into* the kernel and wire it down, there... :<  )
> 
> > That's the kernel command line mem=.  Otherwise, I believe no.
> > And keep in mind that atomic operations, outside of kernel space,
> > might not be possible depending on the architecture.
> 
> Yes.  I was hoping for a kludge/hack that would "usually work"
> (e.g., quiescent systems, etc.) without requiring people to
> have to do any kernel hacking.
> 
> <frown>  I'l have to see if there is another way to approach
> the beast...

So, yeah.  To answer your full question, no, without root you can't do
that.  Sorry :)

-- 
Tom Rini




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