* [PATCHv3] nvme: add 'iopolicy' module parameter
@ 2021-12-20 9:30 Hannes Reinecke
2021-12-20 10:36 ` Sagi Grimberg
0 siblings, 1 reply; 2+ messages in thread
From: Hannes Reinecke @ 2021-12-20 9:30 UTC (permalink / raw)
To: Christoph Hellwig
Cc: Sagi Grimberg, Keith Busch, linux-nvme, Hannes Reinecke,
Chaitanya Kulkarni
While the 'iopolicy' sysfs attribute can be set at runtime, most
storage arrays prefer to use the 'round-robin' iopolicy per default.
We can use udev rules to set this, but is getting rather unwieldy
for rebranded arrays as we would have to update the udev rules
anytime a new array shows up, leading to the same mess we currently
have in multipathd for configuring the RDAC arrays.
Hence this patch adds a module parameter 'iopolicy' to allow the
admin to switch the default, and to do away with the need for a
udev rule here.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
---
drivers/nvme/host/core.c | 4 +---
drivers/nvme/host/multipath.c | 27 +++++++++++++++++++++++++++
drivers/nvme/host/nvme.h | 4 ++++
3 files changed, 32 insertions(+), 3 deletions(-)
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 44c375a1edbb..be404004c235 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2747,9 +2747,7 @@ static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
return -EINVAL;
}
subsys->awupf = le16_to_cpu(id->awupf);
-#ifdef CONFIG_NVME_MULTIPATH
- subsys->iopolicy = NVME_IOPOLICY_NUMA;
-#endif
+ nvme_mpath_default_iopolicy(subsys);
subsys->dev.class = nvme_subsys_class;
subsys->dev.release = nvme_release_subsystem;
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index 7f2071f2460c..de98c0e05777 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -13,6 +13,33 @@ module_param(multipath, bool, 0444);
MODULE_PARM_DESC(multipath,
"turn on native support for multiple controllers per subsystem");
+static int iopolicy = NVME_IOPOLICY_NUMA;
+
+static int nvme_set_iopolicy(const char *val, const struct kernel_param *kp)
+{
+ char *endp;
+ int p;
+
+ if (!val)
+ return -EINVAL;
+ p = simple_strtoul(val, &endp, 0);
+ if (p != NVME_IOPOLICY_NUMA &&
+ p != NVME_IOPOLICY_RR)
+ return -EINVAL;
+ iopolicy = p;
+ return 0;
+}
+
+module_param_call(iopolicy, nvme_set_iopolicy, param_get_int,
+ &iopolicy, 0644);
+MODULE_PARM_DESC(iopolicy,
+ "Default multipath I/O policy; 0 - NUMA (default), 1 - Round-robin");
+
+void nvme_mpath_default_iopolicy(struct nvme_subsystem *subsys)
+{
+ subsys->iopolicy = iopolicy;
+}
+
void nvme_mpath_unfreeze(struct nvme_subsystem *subsys)
{
struct nvme_ns_head *h;
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index a54096ba0552..fe224016418e 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -767,6 +767,7 @@ static inline bool nvme_ctrl_use_ana(struct nvme_ctrl *ctrl)
void nvme_mpath_unfreeze(struct nvme_subsystem *subsys);
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);
bool nvme_mpath_set_disk_name(struct nvme_ns *ns, char *disk_name, int *flags);
void nvme_failover_req(struct request *req);
void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl);
@@ -864,6 +865,9 @@ static inline void nvme_mpath_wait_freeze(struct nvme_subsystem *subsys)
static inline void nvme_mpath_start_freeze(struct nvme_subsystem *subsys)
{
}
+static inline void nvme_mpath_default_iopolicy(struct nvme_subsystem *subsys)
+{
+}
#endif /* CONFIG_NVME_MULTIPATH */
int nvme_revalidate_zones(struct nvme_ns *ns);
--
2.29.2
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCHv3] nvme: add 'iopolicy' module parameter
2021-12-20 9:30 [PATCHv3] nvme: add 'iopolicy' module parameter Hannes Reinecke
@ 2021-12-20 10:36 ` Sagi Grimberg
0 siblings, 0 replies; 2+ messages in thread
From: Sagi Grimberg @ 2021-12-20 10:36 UTC (permalink / raw)
To: Hannes Reinecke, Christoph Hellwig
Cc: Keith Busch, linux-nvme, Chaitanya Kulkarni
On 12/20/21 11:30 AM, Hannes Reinecke wrote:
> While the 'iopolicy' sysfs attribute can be set at runtime, most
> storage arrays prefer to use the 'round-robin' iopolicy per default.
> We can use udev rules to set this, but is getting rather unwieldy
> for rebranded arrays as we would have to update the udev rules
> anytime a new array shows up, leading to the same mess we currently
> have in multipathd for configuring the RDAC arrays.
>
> Hence this patch adds a module parameter 'iopolicy' to allow the
> admin to switch the default, and to do away with the need for a
> udev rule here.
>
> Signed-off-by: Hannes Reinecke <hare@suse.de>
> Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
> ---
> drivers/nvme/host/core.c | 4 +---
> drivers/nvme/host/multipath.c | 27 +++++++++++++++++++++++++++
> drivers/nvme/host/nvme.h | 4 ++++
> 3 files changed, 32 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index 44c375a1edbb..be404004c235 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -2747,9 +2747,7 @@ static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
> return -EINVAL;
> }
> subsys->awupf = le16_to_cpu(id->awupf);
> -#ifdef CONFIG_NVME_MULTIPATH
> - subsys->iopolicy = NVME_IOPOLICY_NUMA;
> -#endif
> + nvme_mpath_default_iopolicy(subsys);
>
> subsys->dev.class = nvme_subsys_class;
> subsys->dev.release = nvme_release_subsystem;
> diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
> index 7f2071f2460c..de98c0e05777 100644
> --- a/drivers/nvme/host/multipath.c
> +++ b/drivers/nvme/host/multipath.c
> @@ -13,6 +13,33 @@ module_param(multipath, bool, 0444);
> MODULE_PARM_DESC(multipath,
> "turn on native support for multiple controllers per subsystem");
>
> +static int iopolicy = NVME_IOPOLICY_NUMA;
> +
> +static int nvme_set_iopolicy(const char *val, const struct kernel_param *kp)
> +{
> + char *endp;
> + int p;
> +
> + if (!val)
> + return -EINVAL;
> + p = simple_strtoul(val, &endp, 0);
> + if (p != NVME_IOPOLICY_NUMA &&
> + p != NVME_IOPOLICY_RR)
> + return -EINVAL;
> + iopolicy = p;
> + return 0;
> +}
> +
> +module_param_call(iopolicy, nvme_set_iopolicy, param_get_int,
> + &iopolicy, 0644);
> +MODULE_PARM_DESC(iopolicy,
> + "Default multipath I/O policy; 0 - NUMA (default), 1 - Round-robin");
Maybe make this a string? user will set numa|round-robin ? That is the
sysfs interface iirc...
^ permalink raw reply [flat|nested] 2+ messages in thread
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