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Commit 9af76271 authored by David Dillow's avatar David Dillow
Browse files

IB/srp: consolidate hot-path variables into cache lines 



Put the variables accessed together in the hot-path into common
cachelines, and separate them by RW vs RO to avoid false dirtying.
We keep a local copy of the lkey and rkey in the target to avoid
traversing pointers (and associated cache lines) to find them.

Reviewed-by: default avatarBart Van Assche <bvanassche@acm.org>
Signed-off-by: default avatarDavid Dillow <dillowda@ornl.gov>
parent e9684678

drivers/infiniband/ulp/srp/ib_srp.c

+7 −5
Original line number Diff line number Diff line
@@ -768,7 +768,7 @@ static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_target_port *target, 
		struct srp_direct_buf *buf = (void *) cmd->add_data;



		buf->va  = cpu_to_be64(ib_sg_dma_address(ibdev, scat));

		buf->key = cpu_to_be32(dev->mr->rkey);

		buf->key = cpu_to_be32(target->rkey);

		buf->len = cpu_to_be32(ib_sg_dma_len(ibdev, scat));

	} else if (srp_map_fmr(target, scat, count, req,

			       (void *) cmd->add_data)) {
@@ -793,7 +793,7 @@ static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_target_port *target, 
			buf->desc_list[i].va  =

				cpu_to_be64(ib_sg_dma_address(ibdev, sg));

			buf->desc_list[i].key =

				cpu_to_be32(dev->mr->rkey);

				cpu_to_be32(target->rkey);

			buf->desc_list[i].len = cpu_to_be32(dma_len);

			datalen += dma_len;

		}
@@ -806,7 +806,7 @@ static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_target_port *target, 
		buf->table_desc.va  =

			cpu_to_be64(req->cmd->dma + sizeof *cmd + sizeof *buf);

		buf->table_desc.key =

			cpu_to_be32(target->srp_host->srp_dev->mr->rkey);

			cpu_to_be32(target->rkey);

		buf->table_desc.len =

			cpu_to_be32(count * sizeof (struct srp_direct_buf));
@@ -883,7 +883,7 @@ static int srp_post_send(struct srp_target_port *target, 


	list.addr   = iu->dma;

	list.length = len;

	list.lkey   = target->srp_host->srp_dev->mr->lkey;

	list.lkey   = target->lkey;



	wr.next       = NULL;

	wr.wr_id      = (uintptr_t) iu;
@@ -902,7 +902,7 @@ static int srp_post_recv(struct srp_target_port *target, struct srp_iu *iu) 


	list.addr   = iu->dma;

	list.length = iu->size;

	list.lkey   = target->srp_host->srp_dev->mr->lkey;

	list.lkey   = target->lkey;



	wr.next     = NULL;

	wr.wr_id    = (uintptr_t) iu;
@@ -1955,6 +1955,8 @@ static ssize_t srp_create_target(struct device *dev, 
	target->io_class   = SRP_REV16A_IB_IO_CLASS;

	target->scsi_host  = target_host;

	target->srp_host   = host;

	target->lkey	   = host->srp_dev->mr->lkey;

	target->rkey	   = host->srp_dev->mr->rkey;



	spin_lock_init(&target->lock);

	INIT_LIST_HEAD(&target->free_tx);

drivers/infiniband/ulp/srp/ib_srp.h

+19 −12
Original line number Diff line number Diff line
@@ -117,6 +117,24 @@ struct srp_request { 
};



struct srp_target_port {

	/* These are RW in the hot path, and commonly used together */

	struct list_head	free_tx;

	struct list_head	free_reqs;

	spinlock_t		lock;

	s32			req_lim;



	/* These are read-only in the hot path */

	struct ib_cq	       *send_cq ____cacheline_aligned_in_smp;

	struct ib_cq	       *recv_cq;

	struct ib_qp	       *qp;

	u32			lkey;

	u32			rkey;

	enum srp_target_state	state;



	/* Everything above this point is used in the hot path of

	 * command processing. Try to keep them packed into cachelines.

	 */



	__be64			id_ext;

	__be64			ioc_guid;

	__be64			service_id;
@@ -133,23 +151,13 @@ struct srp_target_port { 
	int			path_query_id;



	struct ib_cm_id	       *cm_id;

	struct ib_cq	       *recv_cq;

	struct ib_cq	       *send_cq;

	struct ib_qp	       *qp;



	int			max_ti_iu_len;

	s32			req_lim;



	int			zero_req_lim;



	struct srp_iu	       *rx_ring[SRP_RQ_SIZE];



	spinlock_t		lock;



	struct list_head	free_tx;

	struct srp_iu	       *tx_ring[SRP_SQ_SIZE];



	struct list_head	free_reqs;

	struct srp_iu	       *rx_ring[SRP_RQ_SIZE];

	struct srp_request	req_ring[SRP_CMD_SQ_SIZE];



	struct work_struct	work;
@@ -157,7 +165,6 @@ struct srp_target_port { 
	struct list_head	list;

	struct completion	done;

	int			status;

	enum srp_target_state	state;

	int			qp_in_error;



	struct completion	tsk_mgmt_done;