diff options
| author | Thomas Song <tsong@purestorage.com> | 2024-06-25 08:26:05 -0400 |
|---|---|---|
| committer | Keith Busch <kbusch@kernel.org> | 2024-07-02 06:47:19 -0700 |
| commit | f227345f0a70f011647ae7ae12778bf258ff71f2 (patch) | |
| tree | 1af030333ca32fc3f3197f10a8cd46457435664c /drivers/nvme/host/nvme.h | |
| parent | 3d7c2fd2ea704812867f9586270a2516377482a3 (diff) | |
nvme-multipath: implement "queue-depth" iopolicy
The round-robin path selector is inefficient in cases where there is a
difference in latency between paths. In the presence of one or more
high latency paths the round-robin selector continues to use the high
latency path equally. This results in a bias towards the highest latency
path and can cause a significant decrease in overall performance as IOs
pile on the highest latency path. This problem is acute with NVMe-oF
controllers.
The queue-depth path selector sends I/O down the path with the lowest
number of requests in its request queue. Paths with lower latency will
clear requests more quickly and have less requests queued compared to
higher latency paths. The goal of this path selector is to make more use
of lower latency paths which will bring down overall IO latency and
increase throughput and performance.
Signed-off-by: Thomas Song <tsong@purestorage.com>
[emilne: commandeered patch developed by Thomas Song @ Pure Storage]
Co-developed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Ewan D. Milne <emilne@redhat.com>
Co-developed-by: John Meneghini <jmeneghi@redhat.com>
Signed-off-by: John Meneghini <jmeneghi@redhat.com>
Link: https://lore.kernel.org/linux-nvme/20240509202929.831680-1-jmeneghi@redhat.com/
Tested-by: Marco Patalano <mpatalan@redhat.com>
Tested-by: Jyoti Rani <jrani@purestorage.com>
Tested-by: John Meneghini <jmeneghi@redhat.com>
Reviewed-by: Randy Jennings <randyj@purestorage.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Diffstat (limited to 'drivers/nvme/host/nvme.h')
| -rw-r--r-- | drivers/nvme/host/nvme.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h index c63f2b452369..b512012b7044 100644 --- a/drivers/nvme/host/nvme.h +++ b/drivers/nvme/host/nvme.h @@ -49,6 +49,7 @@ extern unsigned int admin_timeout; extern struct workqueue_struct *nvme_wq; extern struct workqueue_struct *nvme_reset_wq; extern struct workqueue_struct *nvme_delete_wq; +extern struct mutex nvme_subsystems_lock; /* * List of workarounds for devices that required behavior not specified in @@ -195,6 +196,7 @@ enum { NVME_REQ_CANCELLED = (1 << 0), NVME_REQ_USERCMD = (1 << 1), NVME_MPATH_IO_STATS = (1 << 2), + NVME_MPATH_CNT_ACTIVE = (1 << 3), }; static inline struct nvme_request *nvme_req(struct request *req) @@ -360,6 +362,7 @@ struct nvme_ctrl { size_t ana_log_size; struct timer_list anatt_timer; struct work_struct ana_work; + atomic_t nr_active; #endif #ifdef CONFIG_NVME_HOST_AUTH @@ -408,6 +411,7 @@ static inline enum nvme_ctrl_state nvme_ctrl_state(struct nvme_ctrl *ctrl) enum nvme_iopolicy { NVME_IOPOLICY_NUMA, NVME_IOPOLICY_RR, + NVME_IOPOLICY_QD, }; struct nvme_subsystem { |