From 70f36b6001bf596eb411c4b302e84c4824ae8730 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 19 Jan 2017 10:59:07 -0700 Subject: blk-mq: allow resize of scheduler requests Add support for growing the tags associated with a hardware queue, for the scheduler tags. Currently we only support resizing within the limits of the original depth, change that so we can grow it as well by allocating and replacing the existing scheduler tag set. This is similar to how we could increase the software queue depth with the legacy IO stack and schedulers. Signed-off-by: Jens Axboe Reviewed-by: Omar Sandoval --- block/blk-mq-tag.c | 51 ++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 44 insertions(+), 7 deletions(-) (limited to 'block/blk-mq-tag.c') diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c index 5504eb7ed10b..a49ec77c415a 100644 --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -387,19 +387,56 @@ void blk_mq_free_tags(struct blk_mq_tags *tags) kfree(tags); } -int blk_mq_tag_update_depth(struct blk_mq_tags *tags, unsigned int tdepth) +int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx, + struct blk_mq_tags **tagsptr, unsigned int tdepth, + bool can_grow) { - tdepth -= tags->nr_reserved_tags; - if (tdepth > tags->nr_tags) + struct blk_mq_tags *tags = *tagsptr; + + if (tdepth <= tags->nr_reserved_tags) return -EINVAL; + tdepth -= tags->nr_reserved_tags; + /* - * Don't need (or can't) update reserved tags here, they remain - * static and should never need resizing. + * If we are allowed to grow beyond the original size, allocate + * a new set of tags before freeing the old one. */ - sbitmap_queue_resize(&tags->bitmap_tags, tdepth); + if (tdepth > tags->nr_tags) { + struct blk_mq_tag_set *set = hctx->queue->tag_set; + struct blk_mq_tags *new; + bool ret; + + if (!can_grow) + return -EINVAL; + + /* + * We need some sort of upper limit, set it high enough that + * no valid use cases should require more. + */ + if (tdepth > 16 * BLKDEV_MAX_RQ) + return -EINVAL; + + new = blk_mq_alloc_rq_map(set, hctx->queue_num, tdepth, 0); + if (!new) + return -ENOMEM; + ret = blk_mq_alloc_rqs(set, new, hctx->queue_num, tdepth); + if (ret) { + blk_mq_free_rq_map(new); + return -ENOMEM; + } + + blk_mq_free_rqs(set, *tagsptr, hctx->queue_num); + blk_mq_free_rq_map(*tagsptr); + *tagsptr = new; + } else { + /* + * Don't need (or can't) update reserved tags here, they + * remain static and should never need resizing. + */ + sbitmap_queue_resize(&tags->bitmap_tags, tdepth); + } - blk_mq_tag_wakeup_all(tags, false); return 0; } -- cgit v1.2.3