Re: [ECOS] Stress testing JFFS2

[Eric Donnat <e.donnat@silicomp.fr>]

JFFS2's design paper is at:

http://lwn.net/2001/features/OLS/pdf/pdf/jffs2.pdf

While running this particular test, the filesystem is "at least" allocating
as many struct jffs2_raw_node_ref in RAM as the number of write()
calls. Nodes are only cleaned when sectors are erased. So the ramp up
for memory is huge. Since you're writing very few bytes before truncating
them, the amount of flash storage for every write() is small compared to
the size of flash sectors. Thus there are many jffs2_raw_node_ref in ram
just waiting for being freed.

But with the IPAQ, this is not very much a problem. ;-).

On Tue, 07 Oct 2003 12:57:00 +0200
Øyvind Harboe <oyvind.harboe@zylin.com> wrote:

> Today stress testing JFFS2 came up on the agenda, and I wrote a small
> piece that demonstrates a problem with JFFS2 running out of space
> when it shouldn't, leaving a corrupt JFFS2 image and continuously
> allocating more ram.
> 
> [...]

--
Before posting, please read the FAQ: http://sources.redhat.com/fom/ecos
and search the list archive: http://sources.redhat.com/ml/ecos-discuss