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Re: JFFS2 "eating memory" when creating files


On Thu, 2004-03-18 at 15:42, Andrew Lunn wrote:
> > After making the attached changes to fs-ecos.c, things are looking much
> > better, but JFFS2 still "eats" 24 bytes every time I open, write and
> > close a file.
> 
> Im not sure i like this patch as is.

My patch(or experiment rather) you refer to is now moot.

A different patch was committed to CVS which fixed the memory leak upon
umount:

http://ecos.sourceware.org/ml/ecos-patches/2004-03/msg00040.html

> Question: What happens when you open/write/close the same file again
> and again? Does it use the cached information or does it create a new
> cache entry each time?

In my application code, I unmount+mount JFFS2 when all files are closed
to reduce RAM usage to a minimum.

This trades CPU for memory, which is the right thing for my application.

>Your patch should be controlled by a configuration option which
>controls is the cache is flushed on close and the default should be
>not to flush the cache.

This configurable behaviour would be nice, but I'm not quite sure how to
modify JFFS2 to do so, hence I do the unmount+mount at the application
level.

Ideally, I'd like JFFS2 to keep no caches whatsoever and walk the JFFS2
image for every open, read, write, etc.

Øyvind



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