On Thu, May 10, 2018 at 10:24:22AM -0600, Jens Axboe wrote: > bfqd->sb_shift was attempted used as a cache for the sbitmap queue > shift, but we don't need it, as it never changes. Kill it with fire. > > Acked-by: Paolo Valente <[email protected]>
Reviewed-by: Omar Sandoval <[email protected]> > Signed-off-by: Jens Axboe <[email protected]> > --- > block/bfq-iosched.c | 16 +++++++--------- > block/bfq-iosched.h | 6 ------ > 2 files changed, 7 insertions(+), 15 deletions(-) > > diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c > index 0cd8aa80c32d..10294124d597 100644 > --- a/block/bfq-iosched.c > +++ b/block/bfq-iosched.c > @@ -5085,26 +5085,24 @@ void bfq_put_async_queues(struct bfq_data *bfqd, > struct bfq_group *bfqg) > */ > static void bfq_update_depths(struct bfq_data *bfqd, struct sbitmap_queue > *bt) > { > - bfqd->sb_shift = bt->sb.shift; > - > /* > * In-word depths if no bfq_queue is being weight-raised: > * leaving 25% of tags only for sync reads. > * > * In next formulas, right-shift the value > - * (1U<<bfqd->sb_shift), instead of computing directly > - * (1U<<(bfqd->sb_shift - something)), to be robust against > - * any possible value of bfqd->sb_shift, without having to > + * (1U<<bt->sb.shift), instead of computing directly > + * (1U<<(bt->sb.shift - something)), to be robust against > + * any possible value of bt->sb.shift, without having to > * limit 'something'. > */ > /* no more than 50% of tags for async I/O */ > - bfqd->word_depths[0][0] = max((1U<<bfqd->sb_shift)>>1, 1U); > + bfqd->word_depths[0][0] = max((1U << bt->sb.shift) >> 1, 1U); > /* > * no more than 75% of tags for sync writes (25% extra tags > * w.r.t. async I/O, to prevent async I/O from starving sync > * writes) > */ > - bfqd->word_depths[0][1] = max(((1U<<bfqd->sb_shift) * 3)>>2, 1U); > + bfqd->word_depths[0][1] = max(((1U << bt->sb.shift) * 3) >> 2, 1U); > > /* > * In-word depths in case some bfq_queue is being weight- > @@ -5114,9 +5112,9 @@ static void bfq_update_depths(struct bfq_data *bfqd, > struct sbitmap_queue *bt) > * shortage. > */ > /* no more than ~18% of tags for async I/O */ > - bfqd->word_depths[1][0] = max(((1U<<bfqd->sb_shift) * 3)>>4, 1U); > + bfqd->word_depths[1][0] = max(((1U << bt->sb.shift) * 3) >> 4, 1U); > /* no more than ~37% of tags for sync writes (~20% extra tags) */ > - bfqd->word_depths[1][1] = max(((1U<<bfqd->sb_shift) * 6)>>4, 1U); > + bfqd->word_depths[1][1] = max(((1U << bt->sb.shift) * 6) >> 4, 1U); > } > > static int bfq_init_hctx(struct blk_mq_hw_ctx *hctx, unsigned int index) > diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h > index 8ec7ff92cd6f..faac509cb35e 100644 > --- a/block/bfq-iosched.h > +++ b/block/bfq-iosched.h > @@ -636,12 +636,6 @@ struct bfq_data { > struct bfq_queue *bio_bfqq; > > /* > - * Cached sbitmap shift, used to compute depth limits in > - * bfq_update_depths. > - */ > - unsigned int sb_shift; > - > - /* > * Depth limits used in bfq_limit_depth (see comments on the > * function) > */ > -- > 2.7.4 >
