On Fri, 8 Jun 2007 12:48:48 +1000 Neil Brown <[EMAIL PROTECTED]> wrote:

> The following patch will remove the extra seqlock except when we
> actually need it and remove the extra arithmetic - but I haven't
> tested it or reviewed it properly.  I can do that if you think it is
> the right direction.

Yes, the optimisation is valid and looks useful.

>  ./mm/filemap.c |   34 ++++++++++++++++++++++++++++------

It didn't apply - your tree seems different from mine.

> +              *
> +              * NOTE: This access of inode->i_size is not protected
> +              *  and if there is a concurrent update on a 32bit machine,
> +              *  it could return the wrong value.  This could only be a 
> problem
> +              *  if i_size has actually changed to a smaller value before the
> +              *  page became uptodate, and at this point it still has a 
> smaller
> +              *  value, but due to a race while reading, it appears 
> unchanged.
> +              *  The chances of this happening are so small and the 
> consequence
> +              *  sufficiently minor, that the cost of the seqlock seems
> +              *  not to be justified.

please consider incorporating scripts/checkpatch.pl into your patch
preparation toolchain.

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