Is swap really needed when RAM's aplenty

Michael Hennebry hennebry at
Thu Aug 19 21:15:59 UTC 2010

On Thu, 19 Aug 2010, JD wrote:

> Problem comes as Michael explains, that when a process needs a large
> "physically contiguous" chunk of memory, it might not be available.
> That said, usually, requests for physically contiguous memory is only
> needed when wanting to map very large number of DMA pages for
> doing direct physical I/O.
> Otherwise, a process itself does not need to have physically contiguous
> pages. Only the virtual space allocated to that "malloc" or large buffer
> declaration in a program, is contiguous.

Why would malloc or a large buffer declaration
require physically contiguous memory?

Michael   hennebry at
"Pessimist: The glass is half empty.
Optimist:   The glass is half full.
Engineer:   The glass is twice as big as it needs to be."

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