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nvme: Use shared timeout rather than timeout per transaction

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Keep track of the approximate time commands are 'due' and the next
deadline for a command. twice a second, wake up to see if any commands
have entered timeout. If so, quiessce and then enter a recovery mode
half the timeout further in the future to allow the ISR to
complete. Once we exit recovery mode, we go back to operations as
normal.

Sponsored by:		Netflix
Differential Revision:	https://reviews.freebsd.org/D28583
This commit is contained in:
Warner Losh 2021-09-23 16:31:32 -06:00
parent cb13059663
commit 502dc84a8b
3 changed files with 133 additions and 68 deletions
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8
sys/dev/nvme/nvme_ctrlr.c
View File

@ -232,7 +232,8 @@ nvme_ctrlr_post_failed_request(struct nvme_controller *ctrlr,
mtx_lock(&ctrlr->lock);
STAILQ_INSERT_TAIL(&ctrlr->fail_req, req, stailq);
mtx_unlock(&ctrlr->lock);
taskqueue_enqueue(ctrlr->taskqueue, &ctrlr->fail_req_task);
if (!ctrlr->is_dying)
taskqueue_enqueue(ctrlr->taskqueue, &ctrlr->fail_req_task);
}
static void
@ -435,7 +436,8 @@ nvme_ctrlr_reset(struct nvme_controller *ctrlr)
*/
return;
taskqueue_enqueue(ctrlr->taskqueue, &ctrlr->reset_task);
if (!ctrlr->is_dying)
taskqueue_enqueue(ctrlr->taskqueue, &ctrlr->reset_task);
}
static int
@ -1481,6 +1483,8 @@ nvme_ctrlr_destruct(struct nvme_controller *ctrlr, device_t dev)
{
int gone, i;
ctrlr->is_dying = true;
if (ctrlr->resource == NULL)
goto nores;
if (!mtx_initialized(&ctrlr->adminq.lock))

16
sys/dev/nvme/nvme_private.h
View File

@ -151,7 +151,7 @@ struct nvme_tracker {
TAILQ_ENTRY(nvme_tracker) tailq;
struct nvme_request *req;
struct nvme_qpair *qpair;
struct callout timer;
sbintime_t deadline;
bus_dmamap_t payload_dma_map;
uint16_t cid;
@ -159,6 +159,12 @@ struct nvme_tracker {
bus_addr_t prp_bus_addr;
};
enum nvme_recovery {
RECOVERY_NONE = 0, /* Normal operations */
RECOVERY_START, /* Deadline has passed, start recovering */
RECOVERY_RESET, /* This pass, initiate reset of controller */
RECOVERY_WAITING, /* waiting for the reset to complete */
};
struct nvme_qpair {
struct nvme_controller *ctrlr;
uint32_t id;
@ -170,6 +176,11 @@ struct nvme_qpair {
struct resource *res;
void *tag;
struct callout timer;
sbintime_t deadline;
bool timer_armed;
enum nvme_recovery recovery_state;
uint32_t num_entries;
uint32_t num_trackers;
uint32_t sq_tdbl_off;
@ -201,8 +212,6 @@ struct nvme_qpair {
struct nvme_tracker **act_tr;
bool is_enabled;
struct mtx lock __aligned(CACHE_LINE_SIZE);
} __aligned(CACHE_LINE_SIZE);
@ -305,6 +314,7 @@ struct nvme_controller {
uint32_t notification_sent;
bool is_failed;
bool is_dying;
STAILQ_HEAD(, nvme_request) fail_req;
/* Host Memory Buffer */

177
sys/dev/nvme/nvme_qpair.c
View File

@ -452,7 +452,6 @@ nvme_qpair_complete_tracker(struct nvme_tracker *tr,
}
mtx_lock(&qpair->lock);
callout_stop(&tr->timer);
if (retry) {
req->retries++;
@ -544,7 +543,7 @@ nvme_qpair_process_completions(struct nvme_qpair *qpair)
* progress. Ignore the interrupt - any I/O that was associated with
* this interrupt will get retried when the reset is complete.
*/
if (!qpair->is_enabled)
if (qpair->recovery_state != RECOVERY_NONE)
return (false);
bus_dmamap_sync(qpair->dma_tag, qpair->queuemem_map,
@ -739,6 +738,10 @@ nvme_qpair_construct(struct nvme_qpair *qpair,
qpair->cpl_bus_addr = queuemem_phys + cmdsz;
prpmem_phys = queuemem_phys + cmdsz + cplsz;
callout_init(&qpair->timer, 1);
qpair->timer_armed = false;
qpair->recovery_state = RECOVERY_NONE;
/*
* Calcuate the stride of the doorbell register. Many emulators set this
* value to correspond to a cache line. However, some hardware has set
@ -776,7 +779,6 @@ nvme_qpair_construct(struct nvme_qpair *qpair,
DOMAINSET_PREF(qpair->domain), M_ZERO | M_WAITOK);
bus_dmamap_create(qpair->dma_tag_payload, 0,
&tr->payload_dma_map);
callout_init(&tr->timer, 1);
tr->cid = i;
tr->qpair = qpair;
tr->prp = (uint64_t *)prp_list;
@ -835,6 +837,8 @@ nvme_qpair_destroy(struct nvme_qpair *qpair)
{
struct nvme_tracker *tr;
callout_drain(&qpair->timer);
if (qpair->tag) {
bus_teardown_intr(qpair->ctrlr->dev, qpair->res, qpair->tag);
qpair->tag = NULL;
@ -914,65 +918,101 @@ nvme_io_qpair_destroy(struct nvme_qpair *qpair)
}
static void
nvme_abort_complete(void *arg, const struct nvme_completion *status)
nvme_qpair_timeout(void *arg)
{
struct nvme_tracker *tr = arg;
/*
* If cdw0 == 1, the controller was not able to abort the command
* we requested. We still need to check the active tracker array,
* to cover race where I/O timed out at same time controller was
* completing the I/O.
*/
if (status->cdw0 == 1 && tr->qpair->act_tr[tr->cid] != NULL) {
/*
* An I/O has timed out, and the controller was unable to
* abort it for some reason. Construct a fake completion
* status, and then complete the I/O's tracker manually.
*/
nvme_printf(tr->qpair->ctrlr,
"abort command failed, aborting command manually\n");
nvme_qpair_manual_complete_tracker(tr,
NVME_SCT_GENERIC, NVME_SC_ABORTED_BY_REQUEST, 0, ERROR_PRINT_ALL);
}
}
static void
nvme_timeout(void *arg)
{
struct nvme_tracker *tr = arg;
struct nvme_qpair *qpair = tr->qpair;
struct nvme_qpair *qpair = arg;
struct nvme_controller *ctrlr = qpair->ctrlr;
struct nvme_tracker *tr;
struct nvme_tracker *tr_temp;
sbintime_t now;
bool idle;
uint32_t csts;
uint8_t cfs;
/*
* Read csts to get value of cfs - controller fatal status.
* If no fatal status, try to call the completion routine, and
* if completes transactions, report a missed interrupt and
* return (this may need to be rate limited). Otherwise, if
* aborts are enabled and the controller is not reporting
* fatal status, abort the command. Otherwise, just reset the
* controller and hope for the best.
*/
csts = nvme_mmio_read_4(ctrlr, csts);
cfs = (csts >> NVME_CSTS_REG_CFS_SHIFT) & NVME_CSTS_REG_CFS_MASK;
if (cfs == 0 && nvme_qpair_process_completions(qpair)) {
nvme_printf(ctrlr, "Missing interrupt\n");
return;
}
if (ctrlr->enable_aborts && cfs == 0) {
nvme_printf(ctrlr, "Aborting command due to a timeout.\n");
nvme_ctrlr_cmd_abort(ctrlr, tr->cid, qpair->id,
nvme_abort_complete, tr);
} else {
mtx_lock(&qpair->lock);
idle = TAILQ_EMPTY(&qpair->outstanding_tr);
again:
switch (qpair->recovery_state) {
case RECOVERY_NONE:
if (idle)
break;
now = getsbinuptime();
TAILQ_FOREACH_SAFE(tr, &qpair->outstanding_tr, tailq, tr_temp) {
if (now > tr->deadline && tr->deadline != 0) {
/*
* We're now passed our earliest deadline. We
* need to do expensive things to cope, but next
* time. Flag that and close the door to any
* further processing.
*/
qpair->recovery_state = RECOVERY_START;
nvme_printf(ctrlr, "RECOVERY_START %jd vs %jd\n",
(uintmax_t)now, (uintmax_t)tr->deadline);
break;
}
}
break;
case RECOVERY_START:
/*
* Read csts to get value of cfs - controller fatal status.
* If no fatal status, try to call the completion routine, and
* if completes transactions, report a missed interrupt and
* return (this may need to be rate limited). Otherwise, if
* aborts are enabled and the controller is not reporting
* fatal status, abort the command. Otherwise, just reset the
* controller and hope for the best.
*/
csts = nvme_mmio_read_4(ctrlr, csts);
cfs = (csts >> NVME_CSTS_REG_CFS_SHIFT) & NVME_CSTS_REG_CFS_MASK;
if (cfs) {
nvme_printf(ctrlr, "Controller in fatal status, resetting\n");
qpair->recovery_state = RECOVERY_RESET;
goto again;
}
mtx_unlock(&qpair->lock);
if (nvme_qpair_process_completions(qpair)) {
nvme_printf(ctrlr, "Completions present in output without an interrupt\n");
qpair->recovery_state = RECOVERY_NONE;
} else {
nvme_printf(ctrlr, "timeout with nothing complete, resetting\n");
qpair->recovery_state = RECOVERY_RESET;
mtx_lock(&qpair->lock);
goto again;
}
mtx_lock(&qpair->lock);
break;
case RECOVERY_RESET:
/*
* If we get here due to a possible surprise hot-unplug event,
* then we let nvme_ctrlr_reset confirm and fail the
* controller.
*/
nvme_printf(ctrlr, "Resetting controller due to a timeout%s.\n",
(csts == NVME_GONE) ? " and possible hot unplug" :
(cfs ? " and fatal error status" : ""));
cfs ? " and fatal error status" : "");
nvme_printf(ctrlr, "RECOVERY_WAITING\n");
qpair->recovery_state = RECOVERY_WAITING;
nvme_ctrlr_reset(ctrlr);
break;
case RECOVERY_WAITING:
nvme_printf(ctrlr, "waiting\n");
break;
}
/*
* Rearm the timeout.
*/
if (!idle) {
callout_schedule(&qpair->timer, hz / 2);
} else {
qpair->timer_armed = false;
}
mtx_unlock(&qpair->lock);
}
/*
* Submit the tracker to the hardware. Must already be in the
* outstanding queue when called.
*/
void
nvme_qpair_submit_tracker(struct nvme_qpair *qpair, struct nvme_tracker *tr)
{
@ -989,12 +1029,17 @@ nvme_qpair_submit_tracker(struct nvme_qpair *qpair, struct nvme_tracker *tr)
if (req->timeout) {
if (req->cb_fn == nvme_completion_poll_cb)
timeout = hz;
timeout = 1;
else
timeout = ctrlr->timeout_period * hz;
callout_reset_on(&tr->timer, timeout, nvme_timeout, tr,
qpair->cpu);
}
timeout = ctrlr->timeout_period;
tr->deadline = getsbinuptime() + timeout * SBT_1S;
if (!qpair->timer_armed) {
qpair->timer_armed = true;
callout_reset_on(&qpair->timer, hz / 2,
nvme_qpair_timeout, qpair, qpair->cpu);
}
} else
tr->deadline = SBT_MAX;
/* Copy the command from the tracker to the submission queue. */
memcpy(&qpair->cmd[qpair->sq_tail], &req->cmd, sizeof(req->cmd));
@ -1069,7 +1114,7 @@ _nvme_qpair_submit_request(struct nvme_qpair *qpair, struct nvme_request *req)
tr = TAILQ_FIRST(&qpair->free_tr);
req->qpair = qpair;
if (tr == NULL || !qpair->is_enabled) {
if (tr == NULL || qpair->recovery_state != RECOVERY_NONE) {
/*
* No tracker is available, or the qpair is disabled due to
* an in-progress controller-level reset or controller
@ -1096,6 +1141,8 @@ _nvme_qpair_submit_request(struct nvme_qpair *qpair, struct nvme_request *req)
TAILQ_REMOVE(&qpair->free_tr, tr, tailq);
TAILQ_INSERT_TAIL(&qpair->outstanding_tr, tr, tailq);
if (!qpair->timer_armed)
tr->deadline = SBT_MAX;
tr->req = req;
switch (req->type) {
@ -1164,8 +1211,9 @@ nvme_qpair_submit_request(struct nvme_qpair *qpair, struct nvme_request *req)
static void
nvme_qpair_enable(struct nvme_qpair *qpair)
{
mtx_assert(&qpair->lock, MA_OWNED);
qpair->is_enabled = true;
qpair->recovery_state = RECOVERY_NONE;
}
void
@ -1208,7 +1256,9 @@ nvme_admin_qpair_enable(struct nvme_qpair *qpair)
NVME_SC_ABORTED_BY_REQUEST, DO_NOT_RETRY, ERROR_PRINT_ALL);
}
mtx_lock(&qpair->lock);
nvme_qpair_enable(qpair);
mtx_unlock(&qpair->lock);
}
void
@ -1251,12 +1301,13 @@ nvme_io_qpair_enable(struct nvme_qpair *qpair)
static void
nvme_qpair_disable(struct nvme_qpair *qpair)
{
struct nvme_tracker *tr;
struct nvme_tracker *tr, *tr_temp;
qpair->is_enabled = false;
mtx_lock(&qpair->lock);
TAILQ_FOREACH(tr, &qpair->outstanding_tr, tailq)
callout_stop(&tr->timer);
qpair->recovery_state = RECOVERY_WAITING;
TAILQ_FOREACH_SAFE(tr, &qpair->outstanding_tr, tailq, tr_temp) {
tr->deadline = SBT_MAX;
}
mtx_unlock(&qpair->lock);
}