blk-mq: rework flush sequencing logic (18741986) · Commits · 戴 / test

block/blk-core.c

+12 −3

Original line number	Diff line number	Diff line
		@@ -693,11 +693,20 @@ blk_init_queue_node(request_fn_proc rfn, spinlock_t lock, int node_id)
		if (!uninit_q)
		return NULL;

		uninit_q->flush_rq = kzalloc(sizeof(struct request), GFP_KERNEL);
		if (!uninit_q->flush_rq)
		goto out_cleanup_queue;

		q = blk_init_allocated_queue(uninit_q, rfn, lock);
		if (!q)
		blk_cleanup_queue(uninit_q);

		goto out_free_flush_rq;
		return q;

		out_free_flush_rq:
		kfree(uninit_q->flush_rq);
		out_cleanup_queue:
		blk_cleanup_queue(uninit_q);
		return NULL;
		}
		EXPORT_SYMBOL(blk_init_queue_node);

		@@ -1127,7 +1136,7 @@ static struct request blk_old_get_request(struct request_queue q, int rw,
		struct request blk_get_request(struct request_queue q, int rw, gfp_t gfp_mask)
		{
		if (q->mq_ops)
		return blk_mq_alloc_request(q, rw, gfp_mask, false);
		return blk_mq_alloc_request(q, rw, gfp_mask);
		else
		return blk_old_get_request(q, rw, gfp_mask);
		}

block/blk-flush.c

+38 −67

Original line number	Diff line number	Diff line
		@@ -130,20 +130,26 @@ static void blk_flush_restore_request(struct request *rq)
		blk_clear_rq_complete(rq);
		}

		static void mq_flush_data_run(struct work_struct *work)
		static void mq_flush_run(struct work_struct *work)
		{
		struct request *rq;

		rq = container_of(work, struct request, mq_flush_data);
		rq = container_of(work, struct request, mq_flush_work);

		memset(&rq->csd, 0, sizeof(rq->csd));
		blk_mq_run_request(rq, true, false);
		}

		static void blk_mq_flush_data_insert(struct request *rq)
		static bool blk_flush_queue_rq(struct request *rq)
		{
		INIT_WORK(&rq->mq_flush_data, mq_flush_data_run);
		kblockd_schedule_work(rq->q, &rq->mq_flush_data);
		if (rq->q->mq_ops) {
		INIT_WORK(&rq->mq_flush_work, mq_flush_run);
		kblockd_schedule_work(rq->q, &rq->mq_flush_work);
		return false;
		} else {
		list_add_tail(&rq->queuelist, &rq->q->queue_head);
		return true;
		}
		}

		/**
		@@ -187,12 +193,7 @@ static bool blk_flush_complete_seq(struct request *rq, unsigned int seq,

		case REQ_FSEQ_DATA:
		list_move_tail(&rq->flush.list, &q->flush_data_in_flight);
		if (q->mq_ops)
		blk_mq_flush_data_insert(rq);
		else {
		list_add(&rq->queuelist, &q->queue_head);
		queued = true;
		}
		queued = blk_flush_queue_rq(rq);
		break;

		case REQ_FSEQ_DONE:
		@@ -216,9 +217,6 @@ static bool blk_flush_complete_seq(struct request *rq, unsigned int seq,
		}

		kicked = blk_kick_flush(q);
		/* blk_mq_run_flush will run queue */
		if (q->mq_ops)
		return queued;
		return kicked \| queued;
		}

		@@ -230,10 +228,9 @@ static void flush_end_io(struct request *flush_rq, int error)
		struct request rq, n;
		unsigned long flags = 0;

		if (q->mq_ops) {
		blk_mq_free_request(flush_rq);
		if (q->mq_ops)
		spin_lock_irqsave(&q->mq_flush_lock, flags);
		}

		running = &q->flush_queue[q->flush_running_idx];
		BUG_ON(q->flush_pending_idx == q->flush_running_idx);

		@@ -263,48 +260,14 @@ static void flush_end_io(struct request *flush_rq, int error)
		* kblockd.
		*/
		if (queued \|\| q->flush_queue_delayed) {
		if (!q->mq_ops)
		WARN_ON(q->mq_ops);
		blk_run_queue_async(q);
		else
		/*
		* This can be optimized to only run queues with requests
		* queued if necessary.
		*/
		blk_mq_run_queues(q, true);
		}
		q->flush_queue_delayed = 0;
		if (q->mq_ops)
		spin_unlock_irqrestore(&q->mq_flush_lock, flags);
		}

		static void mq_flush_work(struct work_struct *work)
		{
		struct request_queue *q;
		struct request *rq;

		q = container_of(work, struct request_queue, mq_flush_work);

		rq = blk_mq_alloc_request(q, WRITE_FLUSH\|REQ_FLUSH_SEQ,
		__GFP_WAIT\|GFP_ATOMIC, false);
		rq->cmd_type = REQ_TYPE_FS;
		rq->end_io = flush_end_io;

		blk_mq_run_request(rq, true, false);
		}

		/*
		* We can't directly use q->flush_rq, because it doesn't have tag and is not in
		* hctx->rqs[]. so we must allocate a new request, since we can't sleep here,
		* so offload the work to workqueue.
		*
		* Note: we assume a flush request finished in any hardware queue will flush
		* the whole disk cache.
		*/
		static void mq_run_flush(struct request_queue *q)
		{
		kblockd_schedule_work(q, &q->mq_flush_work);
		}

		/**
		* blk_kick_flush - consider issuing flush request
		* @q: request_queue being kicked
		@@ -339,19 +302,31 @@ static bool blk_kick_flush(struct request_queue *q)
		* different from running_idx, which means flush is in flight.
		*/
		q->flush_pending_idx ^= 1;

		if (q->mq_ops) {
		mq_run_flush(q);
		return true;
		struct blk_mq_ctx *ctx = first_rq->mq_ctx;
		struct blk_mq_hw_ctx *hctx = q->mq_ops->map_queue(q, ctx->cpu);

		blk_mq_rq_init(hctx, q->flush_rq);
		q->flush_rq->mq_ctx = ctx;

		/*
		* Reuse the tag value from the fist waiting request,
		* with blk-mq the tag is generated during request
		* allocation and drivers can rely on it being inside
		* the range they asked for.
		*/
		q->flush_rq->tag = first_rq->tag;
		} else {
		blk_rq_init(q, q->flush_rq);
		}

		blk_rq_init(q, &q->flush_rq);
		q->flush_rq.cmd_type = REQ_TYPE_FS;
		q->flush_rq.cmd_flags = WRITE_FLUSH \| REQ_FLUSH_SEQ;
		q->flush_rq.rq_disk = first_rq->rq_disk;
		q->flush_rq.end_io = flush_end_io;
		q->flush_rq->cmd_type = REQ_TYPE_FS;
		q->flush_rq->cmd_flags = WRITE_FLUSH \| REQ_FLUSH_SEQ;
		q->flush_rq->rq_disk = first_rq->rq_disk;
		q->flush_rq->end_io = flush_end_io;

		list_add_tail(&q->flush_rq.queuelist, &q->queue_head);
		return true;
		return blk_flush_queue_rq(q->flush_rq);
		}

		static void flush_data_end_io(struct request *rq, int error)
		@@ -407,10 +382,7 @@ void blk_insert_flush(struct request *rq)
		/*
		* @policy now records what operations need to be done. Adjust
		* REQ_FLUSH and FUA for the driver.
		* We keep REQ_FLUSH for mq to track flush requests. For !FUA,
		* we never dispatch the request directly.
		*/
		if (rq->cmd_flags & REQ_FUA)
		rq->cmd_flags &= ~REQ_FLUSH;
		if (!(fflags & REQ_FUA))
		rq->cmd_flags &= ~REQ_FUA;
		@@ -560,5 +532,4 @@ EXPORT_SYMBOL(blkdev_issue_flush);
		void blk_mq_init_flush(struct request_queue *q)
		{
		spin_lock_init(&q->mq_flush_lock);
		INIT_WORK(&q->mq_flush_work, mq_flush_work);
		}

block/blk-mq.c

+19 −35

Original line number	Diff line number	Diff line
		@@ -194,27 +194,9 @@ static void blk_mq_rq_ctx_init(struct request_queue q, struct blk_mq_ctx ctx,
		}

		static struct request __blk_mq_alloc_request(struct blk_mq_hw_ctx hctx,
		gfp_t gfp, bool reserved,
		int rw)
		gfp_t gfp, bool reserved)
		{
		struct request *req;
		bool is_flush = false;
		/*
		* flush need allocate a request, leave at least one request for
		* non-flush IO to avoid deadlock
		*/
		if ((rw & REQ_FLUSH) && !(rw & REQ_FLUSH_SEQ)) {
		if (atomic_inc_return(&hctx->pending_flush) >=
		hctx->queue_depth - hctx->reserved_tags - 1) {
		atomic_dec(&hctx->pending_flush);
		return NULL;
		}
		is_flush = true;
		}
		req = blk_mq_alloc_rq(hctx, gfp, reserved);
		if (!req && is_flush)
		atomic_dec(&hctx->pending_flush);
		return req;
		return blk_mq_alloc_rq(hctx, gfp, reserved);
		}

		static struct request blk_mq_alloc_request_pinned(struct request_queue q,
		@@ -227,7 +209,7 @@ static struct request blk_mq_alloc_request_pinned(struct request_queue q,
		struct blk_mq_ctx *ctx = blk_mq_get_ctx(q);
		struct blk_mq_hw_ctx *hctx = q->mq_ops->map_queue(q, ctx->cpu);

		rq = __blk_mq_alloc_request(hctx, gfp & ~__GFP_WAIT, reserved, rw);
		rq = __blk_mq_alloc_request(hctx, gfp & ~__GFP_WAIT, reserved);
		if (rq) {
		blk_mq_rq_ctx_init(q, ctx, rq, rw);
		break;
		@@ -244,15 +226,14 @@ static struct request blk_mq_alloc_request_pinned(struct request_queue q,
		return rq;
		}

		struct request blk_mq_alloc_request(struct request_queue q, int rw,
		gfp_t gfp, bool reserved)
		struct request blk_mq_alloc_request(struct request_queue q, int rw, gfp_t gfp)
		{
		struct request *rq;

		if (blk_mq_queue_enter(q))
		return NULL;

		rq = blk_mq_alloc_request_pinned(q, rw, gfp, reserved);
		rq = blk_mq_alloc_request_pinned(q, rw, gfp, false);
		if (rq)
		blk_mq_put_ctx(rq->mq_ctx);
		return rq;
		@@ -276,7 +257,7 @@ EXPORT_SYMBOL(blk_mq_alloc_reserved_request);
		/*
		* Re-init and set pdu, if we have it
		*/
		static void blk_mq_rq_init(struct blk_mq_hw_ctx hctx, struct request rq)
		void blk_mq_rq_init(struct blk_mq_hw_ctx hctx, struct request rq)
		{
		blk_rq_init(hctx->queue, rq);

		@@ -290,9 +271,6 @@ static void __blk_mq_free_request(struct blk_mq_hw_ctx *hctx,
		const int tag = rq->tag;
		struct request_queue *q = rq->q;

		if ((rq->cmd_flags & REQ_FLUSH) && !(rq->cmd_flags & REQ_FLUSH_SEQ))
		atomic_dec(&hctx->pending_flush);

		blk_mq_rq_init(hctx, rq);
		blk_mq_put_tag(hctx->tags, tag);

		@@ -946,14 +924,14 @@ static void blk_mq_make_request(struct request_queue q, struct bio bio)
		hctx = q->mq_ops->map_queue(q, ctx->cpu);

		trace_block_getrq(q, bio, rw);
		rq = __blk_mq_alloc_request(hctx, GFP_ATOMIC, false, bio->bi_rw);
		rq = __blk_mq_alloc_request(hctx, GFP_ATOMIC, false);
		if (likely(rq))
		blk_mq_rq_ctx_init(q, ctx, rq, bio->bi_rw);
		blk_mq_rq_ctx_init(q, ctx, rq, rw);
		else {
		blk_mq_put_ctx(ctx);
		trace_block_sleeprq(q, bio, rw);
		rq = blk_mq_alloc_request_pinned(q, bio->bi_rw,
		__GFP_WAIT\|GFP_ATOMIC, false);
		rq = blk_mq_alloc_request_pinned(q, rw, __GFP_WAIT\|GFP_ATOMIC,
		false);
		ctx = rq->mq_ctx;
		hctx = q->mq_ops->map_queue(q, ctx->cpu);
		}
		@@ -1230,9 +1208,7 @@ static int blk_mq_init_hw_queues(struct request_queue *q,
		hctx->queue_num = i;
		hctx->flags = reg->flags;
		hctx->queue_depth = reg->queue_depth;
		hctx->reserved_tags = reg->reserved_tags;
		hctx->cmd_size = reg->cmd_size;
		atomic_set(&hctx->pending_flush, 0);

		blk_mq_init_cpu_notifier(&hctx->cpu_notifier,
		blk_mq_hctx_notify, hctx);
		@@ -1412,9 +1388,14 @@ struct request_queue blk_mq_init_queue(struct blk_mq_reg reg,
		blk_mq_init_flush(q);
		blk_mq_init_cpu_queues(q, reg->nr_hw_queues);

		if (blk_mq_init_hw_queues(q, reg, driver_data))
		q->flush_rq = kzalloc(round_up(sizeof(struct request) + reg->cmd_size,
		cache_line_size()), GFP_KERNEL);
		if (!q->flush_rq)
		goto err_hw;

		if (blk_mq_init_hw_queues(q, reg, driver_data))
		goto err_flush_rq;

		blk_mq_map_swqueue(q);

		mutex_lock(&all_q_mutex);
		@@ -1422,6 +1403,9 @@ struct request_queue blk_mq_init_queue(struct blk_mq_reg reg,
		mutex_unlock(&all_q_mutex);

		return q;

		err_flush_rq:
		kfree(q->flush_rq);
		err_hw:
		kfree(q->mq_map);
		err_map:

block/blk-mq.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -28,6 +28,7 @@ void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async);
		void blk_mq_init_flush(struct request_queue *q);
		void blk_mq_drain_queue(struct request_queue *q);
		void blk_mq_free_queue(struct request_queue *q);
		void blk_mq_rq_init(struct blk_mq_hw_ctx hctx, struct request rq);

		/*
		* CPU hotplug helpers

block/blk-sysfs.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -549,6 +549,8 @@ static void blk_release_queue(struct kobject *kobj)
		if (q->mq_ops)
		blk_mq_free_queue(q);

		kfree(q->flush_rq);

		blk_trace_shutdown(q);

		bdi_destroy(&q->backing_dev_info);

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