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Thu, 10 Apr 2025 01:51:39 -0700 (PDT) Date: Thu, 10 Apr 2025 01:51:37 -0700 From: Mohamed Khalfella To: Daniel Wagner Cc: Christoph Hellwig , Sagi Grimberg , Keith Busch , Hannes Reinecke , John Meneghini , randyj@purestorage.com, linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH RFC 3/3] nvme: delay failover by command quiesce timeout Message-ID: <20250410085137.GE1868505-mkhalfella@purestorage.com> References: <20250324-tp4129-v1-0-95a747b4c33b@kernel.org> <20250324-tp4129-v1-3-95a747b4c33b@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250324-tp4129-v1-3-95a747b4c33b@kernel.org> On 2025-03-24 13:07:58 +0100, Daniel Wagner wrote: > The TP4129 mendates that the failover should be delayed by CQT. Thus when > nvme_decide_disposition returns FAILOVER do not immediately re-queue it on > the namespace level instead queue it on the ctrl's request_list and > moved later to the namespace's requeue_list. > > Signed-off-by: Daniel Wagner > --- > drivers/nvme/host/core.c | 19 ++++++++++++++++ > drivers/nvme/host/fc.c | 4 ++++ > drivers/nvme/host/multipath.c | 52 ++++++++++++++++++++++++++++++++++++++++--- > drivers/nvme/host/nvme.h | 15 +++++++++++++ > drivers/nvme/host/rdma.c | 2 ++ > drivers/nvme/host/tcp.c | 1 + > 6 files changed, 90 insertions(+), 3 deletions(-) > > diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c > index 135045528ea1c79eac0d6d47d5f7f05a7c98acc4..f3155c7735e75e06c4359c26db8931142c067e1d 100644 > --- a/drivers/nvme/host/core.c > +++ b/drivers/nvme/host/core.c > @@ -239,6 +239,7 @@ static void nvme_do_delete_ctrl(struct nvme_ctrl *ctrl) > > flush_work(&ctrl->reset_work); > nvme_stop_ctrl(ctrl); > + nvme_flush_failover(ctrl); > nvme_remove_namespaces(ctrl); > ctrl->ops->delete_ctrl(ctrl); > nvme_uninit_ctrl(ctrl); > @@ -1310,6 +1311,19 @@ static void nvme_queue_keep_alive_work(struct nvme_ctrl *ctrl) > queue_delayed_work(nvme_wq, &ctrl->ka_work, delay); > } > > +void nvme_schedule_failover(struct nvme_ctrl *ctrl) > +{ > + unsigned long delay; > + > + if (ctrl->cqt) > + delay = msecs_to_jiffies(ctrl->cqt); > + else > + delay = ctrl->kato * HZ; I thought that delay = m * ctrl->kato + ctrl->cqt where m = ctrl->ctratt & NVME_CTRL_ATTR_TBKAS ? 3 : 2 no? > + > + queue_delayed_work(nvme_wq, &ctrl->failover_work, delay); > +} > +EXPORT_SYMBOL_GPL(nvme_schedule_failover); > + > static enum rq_end_io_ret nvme_keep_alive_end_io(struct request *rq, > blk_status_t status) > { > @@ -1336,6 +1350,8 @@ static enum rq_end_io_ret nvme_keep_alive_end_io(struct request *rq, > dev_err(ctrl->device, > "failed nvme_keep_alive_end_io error=%d\n", > status); > + > + nvme_schedule_failover(ctrl); > return RQ_END_IO_NONE; > } > > @@ -4716,6 +4732,7 @@ EXPORT_SYMBOL_GPL(nvme_remove_io_tag_set); > > void nvme_stop_ctrl(struct nvme_ctrl *ctrl) > { > + nvme_schedule_failover(ctrl); > nvme_mpath_stop(ctrl); > nvme_auth_stop(ctrl); > nvme_stop_failfast_work(ctrl); > @@ -4842,6 +4859,8 @@ int nvme_init_ctrl(struct nvme_ctrl *ctrl, struct device *dev, > > INIT_DELAYED_WORK(&ctrl->ka_work, nvme_keep_alive_work); > INIT_DELAYED_WORK(&ctrl->failfast_work, nvme_failfast_work); > + INIT_DELAYED_WORK(&ctrl->failover_work, nvme_failover_work); > + INIT_LIST_HEAD(&ctrl->failover_list); > memset(&ctrl->ka_cmd, 0, sizeof(ctrl->ka_cmd)); > ctrl->ka_cmd.common.opcode = nvme_admin_keep_alive; > ctrl->ka_last_check_time = jiffies; > diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c > index cdc1ba277a5c23ef1afd26e6911b082f3d12b215..bd897b29cd286008b781bbcb4230e08019da6b6b 100644 > --- a/drivers/nvme/host/fc.c > +++ b/drivers/nvme/host/fc.c > @@ -2553,6 +2553,8 @@ nvme_fc_error_recovery(struct nvme_fc_ctrl *ctrl, char *errmsg) > { > enum nvme_ctrl_state state = nvme_ctrl_state(&ctrl->ctrl); > > + nvme_schedule_failover(&ctrl->ctrl); > + > /* > * if an error (io timeout, etc) while (re)connecting, the remote > * port requested terminating of the association (disconnect_ls) > @@ -3378,6 +3380,8 @@ nvme_fc_reset_ctrl_work(struct work_struct *work) > /* will block will waiting for io to terminate */ > nvme_fc_delete_association(ctrl); > > + nvme_schedule_failover(&ctrl->ctrl); > + > if (!nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_CONNECTING)) > dev_err(ctrl->ctrl.device, > "NVME-FC{%d}: error_recovery: Couldn't change state " > diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c > index 2a7635565083046c575efe1793362ae10581defd..a14b055796b982df96609f53174a5d1334c1c0c4 100644 > --- a/drivers/nvme/host/multipath.c > +++ b/drivers/nvme/host/multipath.c > @@ -86,9 +86,11 @@ void nvme_mpath_start_freeze(struct nvme_subsystem *subsys) > void nvme_failover_req(struct request *req) > { > struct nvme_ns *ns = req->q->queuedata; > + struct nvme_ctrl *ctrl = nvme_req(req)->ctrl; > u16 status = nvme_req(req)->status & NVME_SCT_SC_MASK; > unsigned long flags; > struct bio *bio; > + enum nvme_ctrl_state state = nvme_ctrl_state(ctrl); > > nvme_mpath_clear_current_path(ns); > > @@ -121,9 +123,53 @@ void nvme_failover_req(struct request *req) > blk_steal_bios(&ns->head->requeue_list, req); > spin_unlock_irqrestore(&ns->head->requeue_lock, flags); > > - nvme_req(req)->status = 0; > - nvme_end_req(req); > - kblockd_schedule_work(&ns->head->requeue_work); > + spin_lock_irqsave(&ctrl->lock, flags); > + list_add_tail(&req->queuelist, &ctrl->failover_list); > + spin_unlock_irqrestore(&ctrl->lock, flags); I see this is the only place where held requests are added to failover_list. - Will this hold admin requests in failover_list? - What about requests that do not go through nvme_failover_req(), like passthrough requests, do we not want to hold these requests until it is safe for them to be retried? - In case of controller reset or delete if nvme_disable_ctrl() successfully disables the controller, then we do not want to add canceled requests to failover_list, right? Does this implementation consider this case? > + > + if (state == NVME_CTRL_DELETING) { > + /* > + * request which fail over in the DELETING state were > + * canceled and blk_mq_tagset_wait_completed_request will > + * block until they have been proceed. Though > + * nvme_failover_work is already stopped. Thus schedule > + * a failover; it's still necessary to delay these commands > + * by CQT. > + */ > + nvme_schedule_failover(ctrl); > + } > +} > + > +void nvme_flush_failover(struct nvme_ctrl *ctrl) > +{ > + LIST_HEAD(failover_list); > + struct request *rq; > + bool kick = false; > + > + spin_lock_irq(&ctrl->lock); > + list_splice_init(&ctrl->failover_list, &failover_list); > + spin_unlock_irq(&ctrl->lock); > + > + while (!list_empty(&failover_list)) { > + rq = list_entry(failover_list.next, > + struct request, queuelist); > + list_del_init(&rq->queuelist); > + > + nvme_req(rq)->status = 0; > + nvme_end_req(rq); > + kick = true; > + } > + > + if (kick) > + nvme_kick_requeue_lists(ctrl); > +} > + > +void nvme_failover_work(struct work_struct *work) > +{ > + struct nvme_ctrl *ctrl = container_of(to_delayed_work(work), > + struct nvme_ctrl, failover_work); > + > + nvme_flush_failover(ctrl); > } > > void nvme_mpath_start_request(struct request *rq) > diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h > index 7563332b5b7b76fc6165ec8c6f2d144737d4fe85..10eb323bdaf139526959180c1e66ab4579bb145d 100644 > --- a/drivers/nvme/host/nvme.h > +++ b/drivers/nvme/host/nvme.h > @@ -411,6 +411,9 @@ struct nvme_ctrl { > > enum nvme_ctrl_type cntrltype; > enum nvme_dctype dctype; > + > + struct delayed_work failover_work; > + struct list_head failover_list; > }; > > static inline enum nvme_ctrl_state nvme_ctrl_state(struct nvme_ctrl *ctrl) > @@ -954,6 +957,9 @@ void nvme_mpath_wait_freeze(struct nvme_subsystem *subsys); > void nvme_mpath_start_freeze(struct nvme_subsystem *subsys); > void nvme_mpath_default_iopolicy(struct nvme_subsystem *subsys); > void nvme_failover_req(struct request *req); > +void nvme_failover_work(struct work_struct *work); > +void nvme_schedule_failover(struct nvme_ctrl *ctrl); > +void nvme_flush_failover(struct nvme_ctrl *ctrl); > void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl); > int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl,struct nvme_ns_head *head); > void nvme_mpath_add_disk(struct nvme_ns *ns, __le32 anagrpid); > @@ -996,6 +1002,15 @@ static inline bool nvme_ctrl_use_ana(struct nvme_ctrl *ctrl) > static inline void nvme_failover_req(struct request *req) > { > } > +static inline void nvme_failover_work(struct work_struct *work) > +{ > +} > +static inline void nvme_schedule_failover(struct nvme_ctrl *ctrl) > +{ > +} > +static inline void nvme_flush_failover(struct nvme_ctrl *ctrl) > +{ > +} > static inline void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl) > { > } > diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c > index 86a2891d9bcc7a990cd214a7fe93fa5c55b292c7..9bee376f881b4c3ebe5502abf23a8e76829780ff 100644 > --- a/drivers/nvme/host/rdma.c > +++ b/drivers/nvme/host/rdma.c > @@ -1127,6 +1127,7 @@ static void nvme_rdma_error_recovery_work(struct work_struct *work) > > nvme_stop_keep_alive(&ctrl->ctrl); > flush_work(&ctrl->ctrl.async_event_work); > + nvme_schedule_failover(&ctrl->ctrl); > nvme_rdma_teardown_io_queues(ctrl, false); > nvme_unquiesce_io_queues(&ctrl->ctrl); > nvme_rdma_teardown_admin_queue(ctrl, false); > @@ -2153,6 +2154,7 @@ static const struct blk_mq_ops nvme_rdma_admin_mq_ops = { > > static void nvme_rdma_shutdown_ctrl(struct nvme_rdma_ctrl *ctrl, bool shutdown) > { > + nvme_schedule_failover(&ctrl->ctrl); > nvme_rdma_teardown_io_queues(ctrl, shutdown); > nvme_quiesce_admin_queue(&ctrl->ctrl); > nvme_disable_ctrl(&ctrl->ctrl, shutdown); > diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c > index d0023bcfd8a79a193adf2807a24481c8c164a174..3a6c1d3febaf233996e4dcf684793327b5d1412f 100644 > --- a/drivers/nvme/host/tcp.c > +++ b/drivers/nvme/host/tcp.c > @@ -2345,6 +2345,7 @@ static void nvme_tcp_error_recovery_work(struct work_struct *work) > > nvme_stop_keep_alive(ctrl); > flush_work(&ctrl->async_event_work); > + nvme_schedule_failover(ctrl); > nvme_tcp_teardown_io_queues(ctrl, false); > /* unquiesce to fail fast pending requests */ > nvme_unquiesce_io_queues(ctrl); > > -- > 2.48.1 >