On Wed, Apr 18, 2018 at 02:30:59PM -0700, Howard McLauchlan wrote:
> Presently, convert_free_space_to_extents() does a linear scan of the
> bitmap. We can speed this up with find_next_{bit,zero_bit}_le().
>
> This patch replaces the linear scan with find_next_{bit,zero_bit}_le().
> Testing shows a 20-33% decrease in execution time for
> convert_free_space_to_extents().
>
> Suggested-by: Omar Sandoval <osan...@osandov.com>
> Signed-off-by: Howard McLauchlan <hmclauch...@fb.com>
> ---
>
> Since we change bitmap to be unsigned long, we have to do some casting for the
> bitmap cursor. In le_bitmap_set() it makes sense to use u8, as we are doing
> bit operations. Everywhere else, we're just using it for pointer arithmetic
> and
> not directly accessing it, so char seems more appropriate.
Ok, makes sense for just passing the pointers around. I'll add the text
to changelog and apply the patch to next.
> - bit = !!le_test_bit(bitnr, bitmap);
This is the last use of le_test_bit, so it can be removed (in another
patch).
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