Re: [Qemu-devel] [PATCH v7 07/20] dirty-bitmap: Track bitmap size by bytes

[John Snow]

On 09/12/2017 04:31 PM, Eric Blake wrote:
> We are still using an internal hbitmap that tracks a size in sectors,
> with the granularity scaled down accordingly, because it lets us
> use a shortcut for our iterators which are currently sector-based.
> But there's no reason we can't track the dirty bitmap size in bytes,
> since it is (mostly) an internal-only variable (remember, the size
> is how many bytes are covered by the bitmap, not how many bytes the
> bitmap occupies).  A later cleanup will convert dirty bitmap
> internals to be entirely byte-based, eliminating the intermediate
> sector rounding added here; and technically, since bdrv_getlength()
> already rounds up to sectors, our use of DIV_ROUND_UP is more for
> theoretical completeness than for any actual rounding.
> 
> Use is_power_of_2() while at it, instead of open-coding that.
> 
> Signed-off-by: Eric Blake <address@hidden>
> 

Reviewed-by: John Snow <address@hidden>