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Commit bd7d4ef6 authored by Jens Axboe's avatar Jens Axboe
Browse files

bfq-iosched: remove unused variable 



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: default avatarPaolo Valente <paolo.valente@linaro.org>
Reviewed-by: default avatarOmar Sandoval <osandov@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent f0635b8a

block/bfq-iosched.c

+7 −9
Original line number Diff line number Diff line
@@ -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)

block/bfq-iosched.h

+0 −6
Original line number Diff line number Diff line
@@ -635,12 +635,6 @@ struct bfq_data { 
	/* bfqq associated with the task issuing current bio for merging */

	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)