linux-kernel - Re: Question about memory mapping mechanism

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Message-id: <45F0ABEB.3030201@shaw.ca>
Date:	Thu, 08 Mar 2007 18:35:55 -0600
From:	Robert Hancock <hancockr@...w.ca>
To:	Martin Drab <drab@...ler.fjfi.cvut.cz>, hugh@...itas.com,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: Question about memory mapping mechanism

Martin Drab wrote:
> Hi,
> 
> I'm writing a driver for a sampling device that is constantly delivering a 
> relatively high amount of data (about 16 MB/s) and I need to deliver the 
> data to the user-space ASAP. To prevent data loss I create a queue of 
> buffers (consisting of few pages each) which are more or less directly 
> filled by the device and then mapped to the user-space via mmap().
> 
> The thing is that I'd like to prevent kernel to swap these pages out, 
> because then I may loose some data when they are not available in time 
> for the next round.

It would likely be easier to just mlock this buffer from the userspace 
application, rather than trying to achieve this in the driver..

-- 
Robert Hancock      Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@...pamshaw.ca
Home Page: http://www.roberthancock.com/

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