Hi Jon,

I was interested to see the problem with YAFFS2 as we too are seeing the long 
mount times.

I took another approach to try to speed things up - I just assumed YAFFS was 
always slow...

Step #1 make the partition smaller as well as the filesystem. I reduced the 
partition down to 256M and added another 256M partition. The effect of this is 
that the original mtd4 becomes mtd5 and I get a newer, smaller mtd3 & mtd4.

Step #2 Use a ramdisk to display a 'splash screen' prior to mounting the root 
file system. Gives the user something on the display after about 20 seconds 
from power up. If there is no console then you don't know that the FLASH mount 
is what is slow ;-) I have had great fun with pivot_root & chroot to get this 
to work.

I can post more details on how to do the above if anybody wants to know more.

Regards

Phil Q 

Phil Quiney, Senior Software Engineer
Trinity Convergence
Cambridge Business Park
Cowley Road
Cambridge CB4 0WZ, UK
T: +44(0)1223-435536
F: +44(0)1223-435560
www.trinityconvergence.com


-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jon Povey
Sent: 24 July 2008 09:19
To: [email protected]
Subject: YAFFS2 with checkpointing on DM355

Hooray, the list is back! :)
Hello again everybody.

I want to get YAFFS2 with checkpointing working on DM355. We are using the MV 
kernel which comes with a 2005 dated implementation of YAFFS2 which does not 
support checkpoints leading to very slow mount times (5.5s with my most 
trimmed-down filesystem so far).

I got the latest YAFFS2 from CVS and it built, but does not work
properly: it mounts an erased partition, you can write some files to it and 
unmount, but it fails to mount again:

mount: wrong fs type, bad option, bad superblock on /dev/mtdblock3, or too many 
mounted file systems

Also if I mount a clean mtd partition and try to untar about 200MB into it, 
half way through or so I start getting a lot of console messages about blocks 
being retired, and eventually "Allocator out!" messages and the partition 
apparently being full. Lots of blocks (seems like most) end up being marked bad 
and flash_erase won't erase them (I used a JTAG programmer to clear them).

If anyone has faced and dealt with these issues then I'd like to hear from you.

My guess from googling around is that it's to do with MTD layer incompatibility 
between MV and recent mainstream kernels so I was going to see how difficult it 
seemed to port the MTD layer back to MV.

The other thought is, I wonder how much work would be needed to get Davinci git 
kernel working on DM355? iirc it's not yet working.

For now I think I will be trying to make the root fs very very very small and 
living with the slow mount time :(

--
Jon Povey, Design Engineer
[EMAIL PROTECTED] | +44(0)1280 825983 

 
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