Date: Sat, 19 Mar 2005 20:17:03 +0100 (MET)
From: Jan Engelhardt <jengelh@linux01.gwdg.de>
To: Baruch Even <baruch@ev-en.org>
cc: linux-kernel@vger.kernel.org
Subject: Re: Relayfs question
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References: <Pine.LNX.4.61.0503191852520.21324@yvahk01.tjqt.qr>
 <423C78E8.3040200@ev-en.org>
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Hi,

>[...]
> The current method is to just manage buffers and enable applications to mmap
> the buffers to read them with some signalling on when a buffer is to be read
> and when the kernel can overwrite it.
>
> A character device is unlikely to need such interface since you do want 16
> bytes of random data and not several pages of mapped random numbers. If you
> really need a lot of random numbers you need something in user-space anyway
> since you'll deplete the kernel entropy pool pretty fast anyway.
>
> If you have a device that needs to transfer lots of data doesn't mind it being
> batched and doesn't really need the character device interface then relayfs
> could be useful.

Ok, urandom was a bad example. I have my tty logger (ttyrpld.sf.net) which 
moves a lot of data (depends) to userspace. It uses a ring buffer of "fixed" 
size (set at module load time). Apart from that relayfs could use a dynamic 
sized ring buffer, I would not see any need to move it to relayfs, would you?


Jan Engelhardt
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