> > I was looking at the nPageReads counter. It gets incremented inside of
> > yaffs_ReadChunkFromNAND() function. Following the function call chain this
> > could be in the following case (assuming page not in cache).
> > yaffs_readpage() -> ... -> yaffs_ReadChunksWithTagsFromNAND(). Inside
> > yaffs_ReadChunkFromNAND function there is the following if statement:
> >
> > if (dev->readChunkWithTagsFromNAND)
> >     result = dev->readChunkWithTagsFromNAND();
> > else
> >     result = yaffs_TagsCompatabilityReadChunkWithTagsFromNAND();
> >
> > Now my question is why is nPageRead incremented in the else case [i.e.,
> > else condition eventually calls yaffs_ReadChunkFromNAND() which increments
> > nPageReads] and not in the if case. Looking at the source code, the if
> > condition also leads to a function - nandmtd2_ReadChunkWithTagsFromNAND()
> > which does a low level mtd->read().
> >
> > Am I missing something here ? Basically, I wanted a count of how many NAND
> > read pages come from the file system and how many are due to flash
> > management.
> 
> No I don't think you are missing something. This is a low-flying bug.
> 
> The history is that the read/write/erase counting were added a long while ago 
> for a once-off profiling exercise and was not kept current. Probably should 
> be fixed :-).
> 
Thanks for the info. I could investigate some more and may be update the profiling info. For
nPageReads, does incrementing the counter for the else part [above] fix the bug ? These were the
only two places where I found an entry point into lower level mtd page writes. 

thanks,
-siddharth


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