Re: mounting jffs2

[Sergei Sharonov <sergei.sharonov@halliburton.com>]

Hi,

> Believe me, if you'll write in 4K chunks, you'll effect much better
> JFFS2 performance. 

I will try that. My log data is comming in 1 kB chunks, so in order to do
4 kB at a time I will have to implement some sort of <power fail safe>
buffering.

> It isn't bug, it is a feature. To facilitate faster mount JFFS2 defers a
> lot of work to the GC thread and performs this work just after mount.
> You may read filesystem but can't write. Any writer will be blocked - in
> your case on 11m10.058s time interval.

Hmm.. ls is not a writer but it is blocked as well.
 
> > Mount and touch were run immediately one after another. I think it may be
> > related to the long umount time problem that I reported before.
> Measure the time of unmount just after mount. If if is also around
> 11m10.058s - this is a bug. Theoretically GC thread must forget its
> deferred work and quit immediately.

Doesn't seem to be the case. Continuing the previous test:

# time mount /mnt/flash/

real    1m33.527s
user    0m0.010s
sys     1m33.471s
# time touch /mnt/flash/junk

real    11m26.228s
user    0m0.010s
sys     0m0.000s
#
#   <------------- previous post ends here ----------
#
# time umount /mnt/flash/

real    0m0.255s
user    0m0.010s
sys     0m0.240s
# time mount /mnt/flash/

real    1m33.517s
user    0m0.010s
sys     1m33.431s
# time umount /mnt/flash/

real    11m25.534s
user    0m0.000s
sys     0m0.250s
#