diff options
| author | Amit Chaudhary <achaudhary@purestorage.com> | 2025-09-26 22:08:22 +0300 |
|---|---|---|
| committer | Keith Busch <kbusch@kernel.org> | 2025-10-09 18:07:01 +0300 |
| commit | bb642e2d300ee27dcede65cda7ffc47a7047bd69 (patch) | |
| tree | a35c41190f0b50ff3f32e78ca4b34463ec30cf61 | |
| parent | 455281c0ef4e2cabdfe2e8b83fa6010d5210811c (diff) | |
| download | linux-bb642e2d300ee27dcede65cda7ffc47a7047bd69.tar.xz | |
nvme-multipath: Skip nr_active increments in RETRY disposition
For queue-depth I/O policy, this patch fixes unbalanced I/Os across
nvme multipaths.
Issue Description:
The RETRY disposition incorrectly increments ns->ctrl->nr_active
counter and reinitializes iostat start-time. In such cases nr_active
counter never goes back to zero until that path disconnects and
reconnects.
Such a path is not chosen for new I/Os if multiple RETRY cases on a given
a path cause its queue-depth counter to be artificially higher compared
to other paths. This leads to unbalanced I/Os across paths.
The patch skips incrementing nr_active if NVME_MPATH_CNT_ACTIVE is already
set. And it skips restarting io stats if NVME_MPATH_IO_STATS is already set.
base-commit: e989a3da2d371a4b6597ee8dee5c72e407b4db7a
Fixes: d4d957b53d91eeb ("nvme-multipath: support io stats on the mpath device")
Signed-off-by: Amit Chaudhary <achaudhary@purestorage.com>
Reviewed-by: Randy Jennings <randyj@purestorage.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
| -rw-r--r-- | drivers/nvme/host/multipath.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c index 3da980dc60d9..543e17aead12 100644 --- a/drivers/nvme/host/multipath.c +++ b/drivers/nvme/host/multipath.c @@ -182,12 +182,14 @@ void nvme_mpath_start_request(struct request *rq) struct nvme_ns *ns = rq->q->queuedata; struct gendisk *disk = ns->head->disk; - if (READ_ONCE(ns->head->subsys->iopolicy) == NVME_IOPOLICY_QD) { + if ((READ_ONCE(ns->head->subsys->iopolicy) == NVME_IOPOLICY_QD) && + !(nvme_req(rq)->flags & NVME_MPATH_CNT_ACTIVE)) { atomic_inc(&ns->ctrl->nr_active); nvme_req(rq)->flags |= NVME_MPATH_CNT_ACTIVE; } - if (!blk_queue_io_stat(disk->queue) || blk_rq_is_passthrough(rq)) + if (!blk_queue_io_stat(disk->queue) || blk_rq_is_passthrough(rq) || + (nvme_req(rq)->flags & NVME_MPATH_IO_STATS)) return; nvme_req(rq)->flags |= NVME_MPATH_IO_STATS; |