Re: Fast shutdown

On Tue, Nov 12, 2002 at 04:04:39PM +0100, GOTZON ASTONDOA wrote:

Hi all:

	Our custom board has to microprocessors: 68K and PowerPC. We have
instaled Linux in the PowerPc side.
	When the user suddenly shutdowns the board, the 68K sends an
interrupt to the PowerPC.We have more or less 8 mSeg to close all the Linux
system (it has hard disk, ethernet, ftp and our own application).

	Can somebody tell me any idea to close the Linux system in the
fastest way? We are thinking in capture the interrupt signal, but, is it
enough fast?

You'll probably want to dump /sbin/init, at least.

Just throwing something out for starters....

You could have an interrupt handler watching the signal from the 68k,
and sending a message via named pipe (perhaps) to a userspace program.
The userspace program would signal all your other programs, sync(),
then wait for powerdown.

I think you'll want all your processes doing synchronous i/o, so that
you don't have much in the way of unwritten disk data to worry with.
You'll probably also want a journaled filesystem, for those times when
8ms just isn't enough...

Hope this gives you a good starting point,


b.g.
--
Bill Gatliff
Embedded systems and Free Software.  Yea, it *is* all that!
See http://billgatliff.com for details.

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