diff options
| -rw-r--r-- | block/bfq-iosched.c | 97 |
1 files changed, 50 insertions, 47 deletions
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index db38e88a5670..0cd8aa80c32d 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -487,46 +487,6 @@ static struct request *bfq_choose_req(struct bfq_data *bfqd, } /* - * See the comments on bfq_limit_depth for the purpose of - * the depths set in the function. - */ -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 - * limit 'something'. - */ - /* no more than 50% of tags for async I/O */ - bfqd->word_depths[0][0] = max((1U<<bfqd->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); - - /* - * In-word depths in case some bfq_queue is being weight- - * raised: leaving ~63% of tags for sync reads. This is the - * highest percentage for which, in our tests, application - * start-up times didn't suffer from any regression due to tag - * shortage. - */ - /* no more than ~18% of tags for async I/O */ - bfqd->word_depths[1][0] = max(((1U<<bfqd->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); -} - -/* * Async I/O can easily starve sync I/O (both sync reads and sync * writes), by consuming all tags. Similarly, storms of sync writes, * such as those that sync(2) may trigger, can starve sync reads. @@ -535,18 +495,11 @@ static void bfq_update_depths(struct bfq_data *bfqd, struct sbitmap_queue *bt) */ static void bfq_limit_depth(unsigned int op, struct blk_mq_alloc_data *data) { - struct blk_mq_tags *tags = blk_mq_tags_from_data(data); struct bfq_data *bfqd = data->q->elevator->elevator_data; - struct sbitmap_queue *bt; if (op_is_sync(op) && !op_is_write(op)) return; - bt = &tags->bitmap_tags; - - if (unlikely(bfqd->sb_shift != bt->sb.shift)) - bfq_update_depths(bfqd, bt); - data->shallow_depth = bfqd->word_depths[!!bfqd->wr_busy_queues][op_is_sync(op)]; @@ -5126,6 +5079,55 @@ void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg) __bfq_put_async_bfqq(bfqd, &bfqg->async_idle_bfqq); } +/* + * See the comments on bfq_limit_depth for the purpose of + * the depths set in the function. + */ +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 + * limit 'something'. + */ + /* no more than 50% of tags for async I/O */ + bfqd->word_depths[0][0] = max((1U<<bfqd->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); + + /* + * In-word depths in case some bfq_queue is being weight- + * raised: leaving ~63% of tags for sync reads. This is the + * highest percentage for which, in our tests, application + * start-up times didn't suffer from any regression due to tag + * shortage. + */ + /* no more than ~18% of tags for async I/O */ + bfqd->word_depths[1][0] = max(((1U<<bfqd->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); +} + +static int bfq_init_hctx(struct blk_mq_hw_ctx *hctx, unsigned int index) +{ + struct bfq_data *bfqd = hctx->queue->elevator->elevator_data; + struct blk_mq_tags *tags = hctx->sched_tags; + + bfq_update_depths(bfqd, &tags->bitmap_tags); + return 0; +} + static void bfq_exit_queue(struct elevator_queue *e) { struct bfq_data *bfqd = e->elevator_data; @@ -5547,6 +5549,7 @@ static struct elevator_type iosched_bfq_mq = { .requests_merged = bfq_requests_merged, .request_merged = bfq_request_merged, .has_work = bfq_has_work, + .init_hctx = bfq_init_hctx, .init_sched = bfq_init_queue, .exit_sched = bfq_exit_queue, }, |