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Message-ID: <20240306231253.8100-1-witu@nvidia.com>
Date: Thu, 7 Mar 2024 01:12:52 +0200
From: William Tu <witu@...dia.com>
To: <netdev@...r.kernel.org>
CC: <jiri@...dia.com>, <bodong@...dia.com>, <tariqt@...dia.com>,
<yossiku@...dia.com>, <kuba@...nel.org>, <witu@...dia.com>
Subject: [PATCH RFC v3 net-next 1/2] devlink: Add shared memory pool eswitch attribute
Add eswitch attribute spool_size for shared memory pool size.
When using switchdev mode, the representor ports handles the slow path
traffic, the traffic that can't be offloaded will be redirected to the
representor port for processing. Memory consumption of the representor
port's rx buffer can grow to several GB when scaling to 1k VFs reps.
For example, in mlx5 driver, each RQ, with a typical 1K descriptors,
consumes 3MB of DMA memory for packet buffer in WQEs, and with four
channels, it consumes 4 * 3MB * 1024 = 12GB of memory. And since rep
ports are for slow path traffic, most of these rx DMA memory are idle.
Add spool_size configuration, allowing multiple representor ports
to share a rx memory buffer pool. When enabled, individual representor
doesn't need to allocate its dedicated rx buffer, but just pointing
its rq to the memory pool. This could make the memory being better
utilized. The spool_size represents the number of bytes of the memory
pool. Users can adjust it based on how many reps, total system
memory, or performance expectation.
An example use case:
$ devlink dev eswitch set pci/0000:08:00.0 mode switchdev \
spool-size 4096000
$ devlink dev eswitch show pci/0000:08:00.0
pci/0000:08:00.0: mode legacy inline-mode none encap-mode basic \
spool-size 4096000
Disable the shared memory pool by setting spool_size to 0.
Signed-off-by: William Tu <witu@...dia.com>
---
v3: feedback from Jakub
- introduce 1 attribute instead of 2
- use spool_size == 0 to disable
- spool_size as byte unit, not counts
Question about ENODOCS:
where to add this? the only document about devlink attr is at iproute2
Do I add a new file Documentation/networking/devlink/devlink-eswitch-attr.rst?
---
Documentation/netlink/specs/devlink.yaml | 4 ++++
include/net/devlink.h | 3 +++
include/uapi/linux/devlink.h | 1 +
net/devlink/dev.c | 21 +++++++++++++++++++++
net/devlink/netlink_gen.c | 5 +++--
5 files changed, 32 insertions(+), 2 deletions(-)
diff --git a/Documentation/netlink/specs/devlink.yaml b/Documentation/netlink/specs/devlink.yaml
index cf6eaa0da821..cb46fa9d6664 100644
--- a/Documentation/netlink/specs/devlink.yaml
+++ b/Documentation/netlink/specs/devlink.yaml
@@ -429,6 +429,9 @@ attribute-sets:
name: eswitch-encap-mode
type: u8
enum: eswitch-encap-mode
+ -
+ name: eswitch-spool-size
+ type: u32
-
name: resource-list
type: nest
@@ -1555,6 +1558,7 @@ operations:
- eswitch-mode
- eswitch-inline-mode
- eswitch-encap-mode
+ - eswitch-spool-size
-
name: eswitch-set
diff --git a/include/net/devlink.h b/include/net/devlink.h
index 9ac394bdfbe4..164c543dd7ca 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -1327,6 +1327,9 @@ struct devlink_ops {
int (*eswitch_encap_mode_set)(struct devlink *devlink,
enum devlink_eswitch_encap_mode encap_mode,
struct netlink_ext_ack *extack);
+ int (*eswitch_spool_size_get)(struct devlink *devlink, u32 *p_size);
+ int (*eswitch_spool_size_set)(struct devlink *devlink, u32 size,
+ struct netlink_ext_ack *extack);
int (*info_get)(struct devlink *devlink, struct devlink_info_req *req,
struct netlink_ext_ack *extack);
/**
diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h
index 130cae0d3e20..cbe51be7a08a 100644
--- a/include/uapi/linux/devlink.h
+++ b/include/uapi/linux/devlink.h
@@ -614,6 +614,7 @@ enum devlink_attr {
DEVLINK_ATTR_REGION_DIRECT, /* flag */
+ DEVLINK_ATTR_ESWITCH_SPOOL_SIZE, /* u32 */
/* add new attributes above here, update the policy in devlink.c */
__DEVLINK_ATTR_MAX,
diff --git a/net/devlink/dev.c b/net/devlink/dev.c
index 19dbf540748a..561874424db7 100644
--- a/net/devlink/dev.c
+++ b/net/devlink/dev.c
@@ -633,6 +633,7 @@ static int devlink_nl_eswitch_fill(struct sk_buff *msg, struct devlink *devlink,
{
const struct devlink_ops *ops = devlink->ops;
enum devlink_eswitch_encap_mode encap_mode;
+ u32 spool_size;
u8 inline_mode;
void *hdr;
int err = 0;
@@ -674,6 +675,15 @@ static int devlink_nl_eswitch_fill(struct sk_buff *msg, struct devlink *devlink,
goto nla_put_failure;
}
+ if (ops->eswitch_spool_size_get) {
+ err = ops->eswitch_spool_size_get(devlink, &spool_size);
+ if (err)
+ goto nla_put_failure;
+ err = nla_put_u32(msg, DEVLINK_ATTR_ESWITCH_SPOOL_SIZE, spool_size);
+ if (err)
+ goto nla_put_failure;
+ }
+
genlmsg_end(msg, hdr);
return 0;
@@ -708,10 +718,21 @@ int devlink_nl_eswitch_set_doit(struct sk_buff *skb, struct genl_info *info)
struct devlink *devlink = info->user_ptr[0];
const struct devlink_ops *ops = devlink->ops;
enum devlink_eswitch_encap_mode encap_mode;
+ u32 spool_size;
u8 inline_mode;
int err = 0;
u16 mode;
+ if (info->attrs[DEVLINK_ATTR_ESWITCH_SPOOL_SIZE]) {
+ if (!ops->eswitch_spool_size_set)
+ return -EOPNOTSUPP;
+ spool_size = nla_get_u32(info->attrs[DEVLINK_ATTR_ESWITCH_SPOOL_SIZE]);
+ err = ops->eswitch_spool_size_set(devlink, spool_size,
+ info->extack);
+ if (err)
+ return err;
+ }
+
if (info->attrs[DEVLINK_ATTR_ESWITCH_MODE]) {
if (!ops->eswitch_mode_set)
return -EOPNOTSUPP;
diff --git a/net/devlink/netlink_gen.c b/net/devlink/netlink_gen.c
index c81cf2dd154f..acbf484b28a2 100644
--- a/net/devlink/netlink_gen.c
+++ b/net/devlink/netlink_gen.c
@@ -194,12 +194,13 @@ static const struct nla_policy devlink_eswitch_get_nl_policy[DEVLINK_ATTR_DEV_NA
};
/* DEVLINK_CMD_ESWITCH_SET - do */
-static const struct nla_policy devlink_eswitch_set_nl_policy[DEVLINK_ATTR_ESWITCH_ENCAP_MODE + 1] = {
+static const struct nla_policy devlink_eswitch_set_nl_policy[DEVLINK_ATTR_ESWITCH_SPOOL_SIZE + 1] = {
[DEVLINK_ATTR_BUS_NAME] = { .type = NLA_NUL_STRING, },
[DEVLINK_ATTR_DEV_NAME] = { .type = NLA_NUL_STRING, },
[DEVLINK_ATTR_ESWITCH_MODE] = NLA_POLICY_MAX(NLA_U16, 1),
[DEVLINK_ATTR_ESWITCH_INLINE_MODE] = NLA_POLICY_MAX(NLA_U16, 3),
[DEVLINK_ATTR_ESWITCH_ENCAP_MODE] = NLA_POLICY_MAX(NLA_U8, 1),
+ [DEVLINK_ATTR_ESWITCH_SPOOL_SIZE] = { .type = NLA_U32, },
};
/* DEVLINK_CMD_DPIPE_TABLE_GET - do */
@@ -787,7 +788,7 @@ const struct genl_split_ops devlink_nl_ops[74] = {
.doit = devlink_nl_eswitch_set_doit,
.post_doit = devlink_nl_post_doit,
.policy = devlink_eswitch_set_nl_policy,
- .maxattr = DEVLINK_ATTR_ESWITCH_ENCAP_MODE,
+ .maxattr = DEVLINK_ATTR_ESWITCH_SPOOL_SIZE,
.flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
},
{
--
2.38.1
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