Re: [ECOS] JFFS2 eats memory

[Andrew Lunn <andrew at lunn dot ch>]

On Mon, Jul 12, 2004 at 04:42:11PM +0200, ?yvind Harboe wrote:
> This issue has been discussed before, and although I have a workaround,
> I'd dearly like to have it put to bed since it is starting to cause
> problems elsewhere in my application:
> 
> - My code opens a file for writing with O_TRUNC set, performs
> a single write call, closes the file.
> - After closing the file, JFFS2 has eaten memory.
> - With the attached modifcations to JFFS2, it "only" eats 24 bytes.
> - If I unmount and remount JFFS2, no memory is "lost" and JFFS2 works
> fine.
> 
> Presumably when the raw nodes in the file fragement list are marked as
> obsolete, they are no longer required, but are not freed.
> 
> Q: Is this fundamentally impossible or a "bad idea" to fix?

How much memory are we talking about here in this example?

The cache is there for a reason, so i would not want to
unconditionally disable it. At least you need some CDL to control
between fat & fast and slow & slim.

I would also suggest you consider extending the
CYGNUM_FS_JFFS2_RAW_NODE_REF_CACHE_POOL_SIZE concept to the inode
cache.  You can then control the size of the cache. 

        Andrew

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