Subject: Re: maximum size of 8KB in copyin\out
To: Maen Suleiman <maen.suleiman@gmail.com>
From: Jason Thorpe <thorpej@shagadelic.org>
List: tech-kern
Date: 03/09/2007 15:57:55
On Mar 9, 2007, at 2:14 PM, Maen Suleiman wrote:

> Hi,
>
> We are implmenting copyin\out using DMA engine, and we have noticed
> that the maximum buffer size is 8KB (for example when using 'dd
> if=/dev/sd0c of=/dev/null bs=131072' ) , Is there a reason for this?
> can this size be increased ?

I don't think there's any inherent limit in copyin/copyout.  Physio is  
a different story -- it doesn't use copyin/copyout at all.

>
>
> Thanks in advance

-- thorpej