JFFS2: mount time, SUMMARY and gc.c ?

[Artem B. Bityuckiy]

On Fri, 7 Jan 2005, Steven Scholz wrote:

> Artem B. Bityuckiy wrote:
> 
> >>But still why is it done everytime I boot my target?
> > 
> > This is how JFFS2 implemented. It skips nodes CRC checking during mount 
> > and does this lated in background. Actually, you can't write anything to 
> > your flash untill the GC thread (jffs2_gcd_mtd0) have not completed 
> > checking. But you may read from JFFS2 during that checking process.
> 
> Well but "in background" means 99.9% of cpu time!
At first, if *anybody* tries to write to JFFS2 before it has done 
checking, 
it will be blocked. So if boot processes try to write...

But in your case the GC thread eats CPU...

> And this slows down the start up of important user applications.
You may try to increase the nice value... It is currently hardcoded to 
10 in background.c (search for set_user_nice)...

> 
> Would it help to enable CONFIG_PREEMPT
Don't know, try it. Hope JFFS2 works well with it. I didn't try. I tried 
only SMP and JFFS2 has some locking bugs. MAy be UP+preempt will work 
fine - some locking bugs were recently fixed. 

> 
> 
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/
> 

--
Best Regards,
Artem B. Bityuckiy,
St.-Petersburg, Russia.