Subject: Re: Allocating page frames
To: Eduardo E. Horvath <>
From: Jason Thorpe <>
List: tech-kern
Date: 03/28/1997 10:47:59
On Fri, 28 Mar 1997 10:04:47 -0800 (PST) 
 "Eduardo E. Horvath" <> wrote:

 > Are there any facilities for allocating physical page frames witout
 > mapping them in?  Since I will only be accessing the pages though physical
 > addresses, I don't want to maintain the info about any virtual mappings
 > just so I can free them later on.  

I am currently working on a machine-independent interface for this.  I
assume you need this for some DMA application, perhaps a framegrabber?

I expect to post another revision of my design document soon, once I
get some of the details worked out.  (My i386 bus dma implementation
is about 45% complete, and the allocation of DMA-safe memory is the
current hurdle).

 > As far as I can see, you can allocate a virtual page using
 > vm_page_alloc(), or you can frob the page free list yourself, which is
 > breaks modularity.  Any other ideas?

Jason R. Thorpe                             
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