jffs_file_write

[Finn Hakansson]

On Tue, 25 Jul 2000, David Woodhouse wrote:

> 
> finn at axis.com said:
> >  I cannot understand that. How much time are we talking about? How
> > large is the flash? How long does an erase take? One garbage collect
> > cannot consume more time than (sectors on flash * number of sectors)
> > time I think. 
> 
> After making a few copies of /usr and /lib, then deleting them, I saw it
> take an hour and a half with a 16Mb flash which was about half-full.

Then something else must be very wrong. A garbage collect shouldn't take
more than a few seconds at most. Unless you have a really slow flash chip.


> Now I've implemented buffer writes on chips which support it, that should be
> down to ten minutes. I'm sure the verbose logging over the serial port
> doesn't help :)
> 
> But it's still done in process context, and writes of new nodes have to 
> wait while it's happening. Shifting that into its own kernel thread would 
> be nice, and would also allow us to merge writes. 
> 
> I'm far more concerned by the thing getting corrupted when I abruptly 
> remove power - I'm about to see if I can reproduce it with the patches you 
> committed just before I left - do you have any ideas from the log I posted 
> on the 17th of July?

I'll take a look at it after lunch.

/Finn



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