blk-mq-sched: refactor scheduler initialization (6917ff0b) · Commits · 戴 / test

block/blk-mq-sched.c

+44 −38

Original line number	Diff line number	Diff line
		@@ -432,53 +432,25 @@ static void blk_mq_sched_free_tags(struct blk_mq_tag_set *set,
		}
		}

		int blk_mq_sched_setup(struct request_queue *q)
		static int blk_mq_sched_alloc_tags(struct request_queue *q,
		struct blk_mq_hw_ctx *hctx,
		unsigned int hctx_idx)
		{
		struct blk_mq_tag_set *set = q->tag_set;
		struct blk_mq_hw_ctx *hctx;
		int ret, i;
		int ret;

		/*
		* Default to 256, since we don't split into sync/async like the
		* old code did. Additionally, this is a per-hw queue depth.
		*/
		q->nr_requests = 2 * BLKDEV_MAX_RQ;
		hctx->sched_tags = blk_mq_alloc_rq_map(set, hctx_idx, q->nr_requests,
		set->reserved_tags);
		if (!hctx->sched_tags)
		return -ENOMEM;

		/*
		* We're switching to using an IO scheduler, so setup the hctx
		* scheduler tags and switch the request map from the regular
		* tags to scheduler tags. First allocate what we need, so we
		* can safely fail and fallback, if needed.
		*/
		ret = 0;
		queue_for_each_hw_ctx(q, hctx, i) {
		hctx->sched_tags = blk_mq_alloc_rq_map(set, i,
		q->nr_requests, set->reserved_tags);
		if (!hctx->sched_tags) {
		ret = -ENOMEM;
		break;
		}
		ret = blk_mq_alloc_rqs(set, hctx->sched_tags, i, q->nr_requests);
		ret = blk_mq_alloc_rqs(set, hctx->sched_tags, hctx_idx, q->nr_requests);
		if (ret)
		break;
		}

		/*
		* If we failed, free what we did allocate
		*/
		if (ret) {
		queue_for_each_hw_ctx(q, hctx, i) {
		if (!hctx->sched_tags)
		continue;
		blk_mq_sched_free_tags(set, hctx, i);
		}
		blk_mq_sched_free_tags(set, hctx, hctx_idx);

		return ret;
		}

		return 0;
		}

		void blk_mq_sched_teardown(struct request_queue *q)
		{
		struct blk_mq_tag_set *set = q->tag_set;
		@@ -489,6 +461,40 @@ void blk_mq_sched_teardown(struct request_queue *q)
		blk_mq_sched_free_tags(set, hctx, i);
		}

		int blk_mq_init_sched(struct request_queue q, struct elevator_type e)
		{
		struct blk_mq_hw_ctx *hctx;
		unsigned int i;
		int ret;

		if (!e) {
		q->elevator = NULL;
		return 0;
		}

		/*
		* Default to 256, since we don't split into sync/async like the
		* old code did. Additionally, this is a per-hw queue depth.
		*/
		q->nr_requests = 2 * BLKDEV_MAX_RQ;

		queue_for_each_hw_ctx(q, hctx, i) {
		ret = blk_mq_sched_alloc_tags(q, hctx, i);
		if (ret)
		goto err;
		}

		ret = e->ops.mq.init_sched(q, e);
		if (ret)
		goto err;

		return 0;

		err:
		blk_mq_sched_teardown(q);
		return ret;
		}

		int blk_mq_sched_init(struct request_queue *q)
		{
		int ret;

block/blk-mq-sched.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -32,7 +32,7 @@ void blk_mq_sched_move_to_dispatch(struct blk_mq_hw_ctx *hctx,
		struct list_head *rq_list,
		struct request (get_rq)(struct blk_mq_hw_ctx *));

		int blk_mq_sched_setup(struct request_queue *q);
		int blk_mq_init_sched(struct request_queue q, struct elevator_type e);
		void blk_mq_sched_teardown(struct request_queue *q);

		int blk_mq_sched_init(struct request_queue *q);

block/elevator.c

+12 −20

Original line number	Diff line number	Diff line
		@@ -242,17 +242,12 @@ int elevator_init(struct request_queue q, char name)
		}
		}

		if (e->uses_mq) {
		err = blk_mq_sched_setup(q);
		if (!err)
		err = e->ops.mq.init_sched(q, e);
		} else
		err = e->ops.sq.elevator_init_fn(q, e);
		if (err) {
		if (e->uses_mq)
		blk_mq_sched_teardown(q);
		err = blk_mq_init_sched(q, e);
		else
		err = e->ops.sq.elevator_init_fn(q, e);
		if (err)
		elevator_put(e);
		}
		return err;
		}
		EXPORT_SYMBOL(elevator_init);
		@@ -987,21 +982,18 @@ static int elevator_switch(struct request_queue q, struct elevator_type new_e)
		}

		/* allocate, init and register new elevator */
		if (new_e) {
		if (new_e->uses_mq) {
		err = blk_mq_sched_setup(q);
		if (!err)
		err = new_e->ops.mq.init_sched(q, new_e);
		} else
		if (q->mq_ops)
		err = blk_mq_init_sched(q, new_e);
		else
		err = new_e->ops.sq.elevator_init_fn(q, new_e);
		if (err)
		goto fail_init;

		if (new_e) {
		err = elv_register_queue(q);
		if (err)
		goto fail_register;
		} else
		q->elevator = NULL;
		}

		/* done, kill the old one and finish */
		if (old) {

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