[PATCH] avoid unnnecessary mtd read when read can be satisfied by write buffer

[David Woodhouse]

On Thursday 01 June 2006 15:32, Jörn Engel wrote:
> Not sure whether this micro optimization is worth the code.  A real
> solution would be to have a cache for the full device.  Possibly read
> the device through pagecache somehow (writing obviously should be
> write-through, not write-back).  That would have a significantly
> higher hit rate than your patch.

We haven't written to the device yet, at this point -- this is just the case 
where the data in question exist _only_ in the wbuf, but we're actually 
reading from the flash first _anyway_, with the current code. 

I don't think that caching the compressed nodes from the flash is going to be 
particularly useful -- we already have the page cache for _uncompressed_ 
data. For other things we might want to cache, such as dirents and symlinks, 
we'll do _much_ better to store that in memory for ourselves rather than just 
caching whole pages of the backing store for such sparse content.

-- 
dwmw2