Re: address space reservation functionality?

[Arjan van de Ven]

On Mon, 2005-01-10 at 15:52 -0500, Robert W. Fuller wrote:
> Hi,
> 
> I was wondering if some functionality existed in Linux.  Specifically, 
> in Solaris, you can mmap the null device in order to reserve part of the 
> address space without otherwise consuming resources.  This is detailed 
> in the Solaris manpage null(7D).  The same functionality is also 
> available under Windows NT/XP/2K by calling the VirtualAlloc function 
> with the MEM_RESERVE flag omitting the MEM_COMMIT flag.  Does Linux have 
> a similar mechanism buried somewhere whereby I can reserve a part of the 
> address space and not increase the "virtual size" of the process or the 
> system's idea of the amount of memory in use?  I could not find one by 
> using the source.

malloc() already does this...
what you describe is the default behavior of linux; only when you
actually write to the memory does it get backed by ram.

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