On Mon, 2022-01-10 at 15:29 +0800, Ming Lei wrote: > Only the last sbitmap_word can have different depth, and all the > others > must have same depth of 1U << sb->shift, so not necessary to store it > in > sbitmap_word, and it can be retrieved easily and efficiently by > adding > one internal helper of __map_depth(sb, index). > > Remove 'depth' field from sbitmap_word, then the annotation of > ____cacheline_aligned_in_smp for 'word' isn't needed any more. > > Not see performance effect when running high parallel IOPS test on > null_blk. > > This way saves us one cacheline(usually 64 words) per each > sbitmap_word. > > Cc: Martin Wilck <martin.wilck@xxxxxxxx> > Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> Reviewed-by: Martin Wilck <mwilck@xxxxxxxx>
