@@ -268,6 +268,14 @@ attribute-sets:
doc: The timeout, in nanoseconds, of how long to suspend irq
processing, if event polling finds events
type: uint
+ -
+ name: threaded
+ doc: Whether the napi is configured to operate in threaded polling
+ mode. If this is set to `1` then the NAPI context operates
+ in threaded polling mode.
+ type: u32
+ checks:
+ max: 1
-
name: queue
attributes:
@@ -659,6 +667,7 @@ operations:
- defer-hard-irqs
- gro-flush-timeout
- irq-suspend-timeout
+ - threaded
dump:
request:
attributes:
@@ -711,6 +720,7 @@ operations:
- defer-hard-irqs
- gro-flush-timeout
- irq-suspend-timeout
+ - threaded
kernel-family:
headers: [ "linux/list.h"]
@@ -413,7 +413,18 @@ dependent). The NAPI instance IDs will be assigned in the opposite
order than the process IDs of the kernel threads.
Threaded NAPI is controlled by writing 0/1 to the ``threaded`` file in
-netdev's sysfs directory.
+netdev's sysfs directory. It can also be enabled for a specific napi using
+netlink interface.
+
+For example, using the script:
+
+.. code-block:: bash
+
+ $ kernel-source/tools/net/ynl/pyynl/cli.py \
+ --spec Documentation/netlink/specs/netdev.yaml \
+ --do napi-set \
+ --json='{"id": 66,
+ "threaded": 1}'
.. rubric:: Footnotes
@@ -352,6 +352,7 @@ struct napi_config {
u64 gro_flush_timeout;
u64 irq_suspend_timeout;
u32 defer_hard_irqs;
+ bool threaded;
unsigned int napi_id;
};
@@ -572,6 +573,15 @@ static inline bool napi_complete(struct napi_struct *n)
int dev_set_threaded(struct net_device *dev, bool threaded);
+/*
+ * napi_set_threaded - set napi threaded state
+ * @napi: NAPI context
+ * @threaded: whether this napi does threaded polling
+ *
+ * Return 0 on success and negative errno on failure.
+ */
+int napi_set_threaded(struct napi_struct *napi, bool threaded);
+
void napi_disable(struct napi_struct *n);
void napi_disable_locked(struct napi_struct *n);
@@ -125,6 +125,7 @@ enum {
NETDEV_A_NAPI_DEFER_HARD_IRQS,
NETDEV_A_NAPI_GRO_FLUSH_TIMEOUT,
NETDEV_A_NAPI_IRQ_SUSPEND_TIMEOUT,
+ NETDEV_A_NAPI_THREADED,
__NETDEV_A_NAPI_MAX,
NETDEV_A_NAPI_MAX = (__NETDEV_A_NAPI_MAX - 1)
@@ -6787,6 +6787,30 @@ static void init_gro_hash(struct napi_struct *napi)
napi->gro_bitmask = 0;
}
+int napi_set_threaded(struct napi_struct *napi, bool threaded)
+{
+ if (napi->dev->threaded)
+ return -EINVAL;
+
+ if (threaded) {
+ if (!napi->thread) {
+ int err = napi_kthread_create(napi);
+
+ if (err)
+ return err;
+ }
+ }
+
+ if (napi->config)
+ napi->config->threaded = threaded;
+
+ /* Make sure kthread is created before THREADED bit is set. */
+ smp_mb__before_atomic();
+ assign_bit(NAPI_STATE_THREADED, &napi->state, threaded);
+
+ return 0;
+}
+
int dev_set_threaded(struct net_device *dev, bool threaded)
{
struct napi_struct *napi;
@@ -6798,6 +6822,11 @@ int dev_set_threaded(struct net_device *dev, bool threaded)
return 0;
if (threaded) {
+ /* Check if threaded is set at napi level already */
+ list_for_each_entry(napi, &dev->napi_list, dev_list)
+ if (test_bit(NAPI_STATE_THREADED, &napi->state))
+ return -EINVAL;
+
list_for_each_entry(napi, &dev->napi_list, dev_list) {
if (!napi->thread) {
err = napi_kthread_create(napi);
@@ -6880,6 +6909,8 @@ static void napi_restore_config(struct napi_struct *n)
napi_hash_add(n);
n->config->napi_id = n->napi_id;
}
+
+ napi_set_threaded(n, n->config->threaded);
}
static void napi_save_config(struct napi_struct *n)
@@ -92,11 +92,12 @@ static const struct nla_policy netdev_bind_rx_nl_policy[NETDEV_A_DMABUF_FD + 1]
};
/* NETDEV_CMD_NAPI_SET - do */
-static const struct nla_policy netdev_napi_set_nl_policy[NETDEV_A_NAPI_IRQ_SUSPEND_TIMEOUT + 1] = {
+static const struct nla_policy netdev_napi_set_nl_policy[NETDEV_A_NAPI_THREADED + 1] = {
[NETDEV_A_NAPI_ID] = { .type = NLA_U32, },
[NETDEV_A_NAPI_DEFER_HARD_IRQS] = NLA_POLICY_FULL_RANGE(NLA_U32, &netdev_a_napi_defer_hard_irqs_range),
[NETDEV_A_NAPI_GRO_FLUSH_TIMEOUT] = { .type = NLA_UINT, },
[NETDEV_A_NAPI_IRQ_SUSPEND_TIMEOUT] = { .type = NLA_UINT, },
+ [NETDEV_A_NAPI_THREADED] = NLA_POLICY_MAX(NLA_U32, 1),
};
/* Ops table for netdev */
@@ -187,7 +188,7 @@ static const struct genl_split_ops netdev_nl_ops[] = {
.cmd = NETDEV_CMD_NAPI_SET,
.doit = netdev_nl_napi_set_doit,
.policy = netdev_napi_set_nl_policy,
- .maxattr = NETDEV_A_NAPI_IRQ_SUSPEND_TIMEOUT,
+ .maxattr = NETDEV_A_NAPI_THREADED,
.flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
},
};
@@ -183,6 +183,9 @@ netdev_nl_napi_fill_one(struct sk_buff *rsp, struct napi_struct *napi,
if (napi->irq >= 0 && nla_put_u32(rsp, NETDEV_A_NAPI_IRQ, napi->irq))
goto nla_put_failure;
+ if (nla_put_u32(rsp, NETDEV_A_NAPI_THREADED, !!napi->thread))
+ goto nla_put_failure;
+
if (napi->thread) {
pid = task_pid_nr(napi->thread);
if (nla_put_u32(rsp, NETDEV_A_NAPI_PID, pid))
@@ -321,8 +324,14 @@ netdev_nl_napi_set_config(struct napi_struct *napi, struct genl_info *info)
{
u64 irq_suspend_timeout = 0;
u64 gro_flush_timeout = 0;
+ u32 threaded = 0;
u32 defer = 0;
+ if (info->attrs[NETDEV_A_NAPI_THREADED]) {
+ threaded = nla_get_u32(info->attrs[NETDEV_A_NAPI_THREADED]);
+ napi_set_threaded(napi, !!threaded);
+ }
+
if (info->attrs[NETDEV_A_NAPI_DEFER_HARD_IRQS]) {
defer = nla_get_u32(info->attrs[NETDEV_A_NAPI_DEFER_HARD_IRQS]);
napi_set_defer_hard_irqs(napi, defer);
@@ -125,6 +125,7 @@ enum {
NETDEV_A_NAPI_DEFER_HARD_IRQS,
NETDEV_A_NAPI_GRO_FLUSH_TIMEOUT,
NETDEV_A_NAPI_IRQ_SUSPEND_TIMEOUT,
+ NETDEV_A_NAPI_THREADED,
__NETDEV_A_NAPI_MAX,
NETDEV_A_NAPI_MAX = (__NETDEV_A_NAPI_MAX - 1)
A net device has a threaded sysctl that can be used to enable threaded napi polling on all of the NAPI contexts under that device. Allow enabling threaded napi polling at individual napi level using netlink. Extend the netlink operation `napi-set` and allow setting the threaded attribute of a NAPI. This will enable the threaded polling on a napi context. Tested using following command in qemu/virtio-net: ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \ --do napi-set --json '{"id": 66, "threaded": 1}' Signed-off-by: Samiullah Khawaja <skhawaja@google.com> --- Documentation/netlink/specs/netdev.yaml | 10 ++++++++ Documentation/networking/napi.rst | 13 ++++++++++- include/linux/netdevice.h | 10 ++++++++ include/uapi/linux/netdev.h | 1 + net/core/dev.c | 31 +++++++++++++++++++++++++ net/core/netdev-genl-gen.c | 5 ++-- net/core/netdev-genl.c | 9 +++++++ tools/include/uapi/linux/netdev.h | 1 + 8 files changed, 77 insertions(+), 3 deletions(-)