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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: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Sagi Grimberg 2018-11-02 10:28:15 -07:00 committed by Jens Axboe
parent 3e53ba38a9
commit 6e3ca03ee9
3 changed files with 15 additions and 0 deletions
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13
drivers/nvme/host/core.c
View File

@ -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 */

1
drivers/nvme/host/nvme.h
View File

@ -145,6 +145,7 @@ enum nvme_ctrl_state {
};
struct nvme_ctrl {
bool comp_seen;
enum nvme_ctrl_state state;
bool identified;
spinlock_t lock;

1
include/linux/nvme.h
View File

@ -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 {