How to produce dirty space

How to produce dirty space

[Bernhard Priewasser]

Hi all,

I want to generate some dirty space in a mounted JFFS2 for test 
purposes. I tried to get the FS dirty for hours now... but I couldn't 
compete against the erase_pending list. (BTW: how is kupdated set up?)
Maybe... I'm not the first one who wants to do some tests on a dirty FS, 
perhaps there is some existing code... :-)

Thanks,

-- 
Bernhard

Re: How to produce dirty space

[Artem B. Bityutskiy]

Bernhard Priewasser wrote:
> Hi all,
> 
> I want to generate some dirty space in a mounted JFFS2 for test 
> purposes. I tried to get the FS dirty for hours now... but I couldn't 
> compete against the erase_pending list. (BTW: how is kupdated set up?)
> Maybe... I'm not the first one who wants to do some tests on a dirty FS, 
> perhaps there is some existing code... :-)

Create a file and make a small change in it. It is unlikely that the 
corresponding eraseblock will be garbage collected soon, so you'll have 
dirty space.

For the information when things are flushed see "/proc/sys/vm - the 
virtual memory subsystem" at Documentation/filesystems/proc.txt.

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

Re: How to produce dirty space

[Bernhard Priewasser]

 > For the information when things are flushed see "/proc/sys/vm - the
 > virtual memory subsystem" at Documentation/filesystems/proc.txt.

Got it:

 > [/proc/sys/vm/]dirty_writeback_centisecs
 > ----------------------------------------
 >
 > The pdflush writeback daemons will periodically wake up and write
 > `old' data out to disk.  This tunable expresses the interval between
 >  those wakeups, in 100'ths of a second.

Thanks,
-- 
Bernhard