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Commit 6e3ca03e authored by Sagi Grimberg's avatar Sagi Grimberg Committed by Jens Axboe
Browse files

nvme: support traffic based keep-alive 



If the controller supports traffic based keep alive, we restart the keep
alive timer if any admin or io commands was completed during the kato
period.  This prevents a possible starvation of keep alive commands in
the presence of heavy traffic as in such case, we already have a health
indication from the host perspective.

Only set a comp_seen indicator in case the controller supports keep
alive to minimize the overhead for pci controllers.

Signed-off-by: default avatarSagi Grimberg <sagi@grimberg.me>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 3e53ba38

drivers/nvme/host/core.c

+13 −0
Original line number Diff line number Diff line
@@ -251,6 +251,9 @@ void nvme_complete_rq(struct request *req) 


	trace_nvme_complete_rq(req);



	if (nvme_req(req)->ctrl->kas)

		nvme_req(req)->ctrl->comp_seen = true;



	if (unlikely(status != BLK_STS_OK && nvme_req_needs_retry(req))) {

		if ((req->cmd_flags & REQ_NVME_MPATH) &&

		    blk_path_error(status)) {
@@ -839,6 +842,7 @@ static void nvme_keep_alive_end_io(struct request *rq, blk_status_t status) 
		return;

	}



	ctrl->comp_seen = false;

	schedule_delayed_work(&ctrl->ka_work, ctrl->kato * HZ);

}
@@ -863,6 +867,15 @@ static void nvme_keep_alive_work(struct work_struct *work) 
{

	struct nvme_ctrl *ctrl = container_of(to_delayed_work(work),

			struct nvme_ctrl, ka_work);

	bool comp_seen = ctrl->comp_seen;



	if ((ctrl->ctratt & NVME_CTRL_ATTR_TBKAS) && comp_seen) {

		dev_dbg(ctrl->device,

			"reschedule traffic based keep-alive timer\n");

		ctrl->comp_seen = false;

		schedule_delayed_work(&ctrl->ka_work, ctrl->kato * HZ);

		return;

	}



	if (nvme_keep_alive(ctrl)) {

		/* allocation failure, reset the controller */

drivers/nvme/host/nvme.h

+1 −0
Original line number Diff line number Diff line
@@ -145,6 +145,7 @@ enum nvme_ctrl_state { 
};



struct nvme_ctrl {

	bool comp_seen;

	enum nvme_ctrl_state state;

	bool identified;

	spinlock_t lock;

include/linux/nvme.h

+1 −0
Original line number Diff line number Diff line
@@ -200,6 +200,7 @@ enum { 


enum nvme_ctrl_attr {

	NVME_CTRL_ATTR_HID_128_BIT	= (1 << 0),

	NVME_CTRL_ATTR_TBKAS		= (1 << 6),

};



struct nvme_id_ctrl {