git: 9bbd0a7ca999 - stable/13 - nvme: Use shared timeout rather than timeout per transaction
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Date: Fri, 21 Jan 2022 02:26:50 UTC
The branch stable/13 has been updated by mav:
URL: https://cgit.FreeBSD.org/src/commit/?id=9bbd0a7ca9996d3eee2162ab01ad81d4b15071d8
commit 9bbd0a7ca9996d3eee2162ab01ad81d4b15071d8
Author: Warner Losh <imp@FreeBSD.org>
AuthorDate: 2021-09-23 22:31:32 +0000
Commit: Alexander Motin <mav@FreeBSD.org>
CommitDate: 2022-01-21 02:07:30 +0000
nvme: Use shared timeout rather than timeout per transaction
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
(cherry picked from commit 502dc84a8b6703e7c0626739179a3cdffdd22d81)
---
sys/dev/nvme/nvme_ctrlr.c | 8 +-
sys/dev/nvme/nvme_private.h | 16 +++-
sys/dev/nvme/nvme_qpair.c | 173 ++++++++++++++++++++++++++++----------------
3 files changed, 131 insertions(+), 66 deletions(-)
diff --git a/sys/dev/nvme/nvme_ctrlr.c b/sys/dev/nvme/nvme_ctrlr.c
index 833bf328584a..39cde3f065dd 100644
--- a/sys/dev/nvme/nvme_ctrlr.c
+++ b/sys/dev/nvme/nvme_ctrlr.c
@@ -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))
diff --git a/sys/dev/nvme/nvme_private.h b/sys/dev/nvme/nvme_private.h
index fba1b406e9ce..02cecaf03a97 100644
--- a/sys/dev/nvme/nvme_private.h
+++ b/sys/dev/nvme/nvme_private.h
@@ -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 */
diff --git a/sys/dev/nvme/nvme_qpair.c b/sys/dev/nvme/nvme_qpair.c
index 71718acff66f..7a17a057f319 100644
--- a/sys/dev/nvme/nvme_qpair.c
+++ b/sys/dev/nvme/nvme_qpair.c
@@ -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;
+ 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;
- /*
- * 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) {
+ 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:
/*
- * 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.
+ * 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.
*/
- 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);
+ 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",
+ 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;
}
-}
-
-static void
-nvme_timeout(void *arg)
-{
- struct nvme_tracker *tr = arg;
- struct nvme_qpair *qpair = tr->qpair;
- struct nvme_controller *ctrlr = qpair->ctrlr;
- 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.
+ * Rearm the timeout.
*/
- 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);
+ if (!idle) {
+ callout_schedule(&qpair->timer, hz / 2);
} else {
- nvme_printf(ctrlr, "Resetting controller due to a timeout%s.\n",
- (csts == NVME_GONE) ? " and possible hot unplug" :
- (cfs ? " and fatal error status" : ""));
- nvme_ctrlr_reset(ctrlr);
+ 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);
}