[RFC net-next v2 5/9] net: napi: Make gro_flush_timeout per-NAPI
From: Joe Damato
Date: Sun Sep 08 2024 - 12:10:16 EST
Allow per-NAPI gro_flush_timeout setting.
The existing sysfs parameter is respected; writes to sysfs will write to
all NAPI structs for the device and the net_device gro_flush_timeout
field. Reads from sysfs will read from the net_device field.
The ability to set gro_flush_timeout on specific NAPI instances will be
added in a later commit, via netdev-genl.
Signed-off-by: Joe Damato <jdamato@xxxxxxxxxx>
---
Documentation/netlink/specs/netdev.yaml | 6 +++
.../networking/net_cachelines/net_device.rst | 1 -
include/linux/netdevice.h | 2 +-
include/uapi/linux/netdev.h | 1 +
net/core/dev.c | 12 +++---
net/core/dev.h | 43 +++++++++++++++++++
net/core/net-sysfs.c | 2 +-
net/core/netdev-genl.c | 5 +++
tools/include/uapi/linux/netdev.h | 1 +
9 files changed, 64 insertions(+), 9 deletions(-)
diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
index e4219bfff08d..3034c480d0b4 100644
--- a/Documentation/netlink/specs/netdev.yaml
+++ b/Documentation/netlink/specs/netdev.yaml
@@ -259,6 +259,11 @@ attribute-sets:
type: u32
checks:
max: s32-max
+ -
+ name: gro-flush-timeout
+ doc: The timeout, in nanoseconds, of when to trigger the NAPI
+ watchdog timer and schedule NAPI processing.
+ type: uint
-
name: queue
attributes:
@@ -610,6 +615,7 @@ operations:
- pid
- index
- defer-hard-irqs
+ - gro-flush-timeout
dump:
request:
attributes:
diff --git a/Documentation/networking/net_cachelines/net_device.rst b/Documentation/networking/net_cachelines/net_device.rst
index 4cd801398c4e..048cc9d1eafc 100644
--- a/Documentation/networking/net_cachelines/net_device.rst
+++ b/Documentation/networking/net_cachelines/net_device.rst
@@ -98,7 +98,6 @@ struct_netdev_queue* _rx read_mostly
unsigned_int num_rx_queues
unsigned_int real_num_rx_queues - read_mostly get_rps_cpu
struct_bpf_prog* xdp_prog - read_mostly netif_elide_gro()
-unsigned_long gro_flush_timeout - read_mostly napi_complete_done
unsigned_int gro_max_size - read_mostly skb_gro_receive
unsigned_int gro_ipv4_max_size - read_mostly skb_gro_receive
rx_handler_func_t* rx_handler read_mostly - __netif_receive_skb_core
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 5a58cf61539e..862c835bcf09 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2087,7 +2087,6 @@ struct net_device {
int ifindex;
unsigned int real_num_rx_queues;
struct netdev_rx_queue *_rx;
- unsigned long gro_flush_timeout;
unsigned int gro_max_size;
unsigned int gro_ipv4_max_size;
rx_handler_func_t __rcu *rx_handler;
@@ -2411,6 +2410,7 @@ struct net_device {
/** @irq_moder: dim parameters used if IS_ENABLED(CONFIG_DIMLIB). */
struct dim_irq_moder *irq_moder;
+ unsigned long gro_flush_timeout;
u32 napi_defer_hard_irqs;
u8 priv[] ____cacheline_aligned
diff --git a/include/uapi/linux/netdev.h b/include/uapi/linux/netdev.h
index bcc95b7ebd92..fd02b5b3b081 100644
--- a/include/uapi/linux/netdev.h
+++ b/include/uapi/linux/netdev.h
@@ -123,6 +123,7 @@ enum {
NETDEV_A_NAPI_PID,
NETDEV_A_NAPI_INDEX,
NETDEV_A_NAPI_DEFER_HARD_IRQS,
+ NETDEV_A_NAPI_GRO_FLUSH_TIMEOUT,
__NETDEV_A_NAPI_MAX,
NETDEV_A_NAPI_MAX = (__NETDEV_A_NAPI_MAX - 1)
diff --git a/net/core/dev.c b/net/core/dev.c
index 9495448fedaa..a45a0dbcf711 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6227,12 +6227,12 @@ bool napi_complete_done(struct napi_struct *n, int work_done)
if (work_done) {
if (n->gro_bitmask)
- timeout = READ_ONCE(n->dev->gro_flush_timeout);
+ timeout = napi_get_gro_flush_timeout(n);
n->defer_hard_irqs_count = napi_get_defer_hard_irqs(n);
}
if (n->defer_hard_irqs_count > 0) {
n->defer_hard_irqs_count--;
- timeout = READ_ONCE(n->dev->gro_flush_timeout);
+ timeout = napi_get_gro_flush_timeout(n);
if (timeout)
ret = false;
}
@@ -6367,7 +6367,7 @@ static void busy_poll_stop(struct napi_struct *napi, void *have_poll_lock,
if (flags & NAPI_F_PREFER_BUSY_POLL) {
napi->defer_hard_irqs_count = napi_get_defer_hard_irqs(napi);
- timeout = READ_ONCE(napi->dev->gro_flush_timeout);
+ timeout = napi_get_gro_flush_timeout(napi);
if (napi->defer_hard_irqs_count && timeout) {
hrtimer_start(&napi->timer, ns_to_ktime(timeout), HRTIMER_MODE_REL_PINNED);
skip_schedule = true;
@@ -6649,6 +6649,7 @@ void netif_napi_add_weight(struct net_device *dev, struct napi_struct *napi,
hrtimer_init(&napi->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_PINNED);
napi->timer.function = napi_watchdog;
napi_set_defer_hard_irqs(napi, READ_ONCE(dev->napi_defer_hard_irqs));
+ napi_set_gro_flush_timeout(napi, READ_ONCE(dev->gro_flush_timeout));
init_gro_hash(napi);
napi->skb = NULL;
INIT_LIST_HEAD(&napi->rx_list);
@@ -11033,7 +11034,7 @@ void netdev_sw_irq_coalesce_default_on(struct net_device *dev)
WARN_ON(dev->reg_state == NETREG_REGISTERED);
if (!IS_ENABLED(CONFIG_PREEMPT_RT)) {
- dev->gro_flush_timeout = 20000;
+ netdev_set_gro_flush_timeout(dev, 20000);
netdev_set_defer_hard_irqs(dev, 1);
}
}
@@ -11982,7 +11983,6 @@ static void __init net_dev_struct_check(void)
CACHELINE_ASSERT_GROUP_MEMBER(struct net_device, net_device_read_rx, ifindex);
CACHELINE_ASSERT_GROUP_MEMBER(struct net_device, net_device_read_rx, real_num_rx_queues);
CACHELINE_ASSERT_GROUP_MEMBER(struct net_device, net_device_read_rx, _rx);
- CACHELINE_ASSERT_GROUP_MEMBER(struct net_device, net_device_read_rx, gro_flush_timeout);
CACHELINE_ASSERT_GROUP_MEMBER(struct net_device, net_device_read_rx, gro_max_size);
CACHELINE_ASSERT_GROUP_MEMBER(struct net_device, net_device_read_rx, gro_ipv4_max_size);
CACHELINE_ASSERT_GROUP_MEMBER(struct net_device, net_device_read_rx, rx_handler);
@@ -11995,7 +11995,7 @@ static void __init net_dev_struct_check(void)
CACHELINE_ASSERT_GROUP_MEMBER(struct net_device, net_device_read_rx, tcx_ingress);
#endif
CACHELINE_ASSERT_GROUP_MEMBER(struct net_device, net_device_read_rx, napi_storage);
- CACHELINE_ASSERT_GROUP_SIZE(struct net_device, net_device_read_rx, 108);
+ CACHELINE_ASSERT_GROUP_SIZE(struct net_device, net_device_read_rx, 100);
}
/*
diff --git a/net/core/dev.h b/net/core/dev.h
index 2584a7de189f..f33d7bcb923f 100644
--- a/net/core/dev.h
+++ b/net/core/dev.h
@@ -178,6 +178,49 @@ static inline void netdev_set_defer_hard_irqs(struct net_device *netdev,
napi_set_defer_hard_irqs(napi, defer);
}
+/**
+ * napi_get_gro_flush_timeout - get the gro_flush_timeout
+ * @n: napi struct to get the gro_flush_timeout from
+ *
+ * Return: the per-NAPI value of the gro_flush_timeout field.
+ */
+static inline unsigned long napi_get_gro_flush_timeout(const struct napi_struct *n)
+{
+ if (n->napi_storage)
+ return READ_ONCE(n->napi_storage->gro_flush_timeout);
+ else
+ return READ_ONCE(n->dev->napi_defer_hard_irqs);
+}
+
+/**
+ * napi_set_gro_flush_timeout - set the gro_flush_timeout for a napi
+ * @n: napi struct to set the gro_flush_timeout
+ * @timeout: timeout value to set
+ *
+ * napi_set_gro_flush_timeout sets the per-NAPI gro_flush_timeout
+ */
+static inline void napi_set_gro_flush_timeout(struct napi_struct *n,
+ unsigned long timeout)
+{
+ if (n->napi_storage)
+ WRITE_ONCE(n->napi_storage->gro_flush_timeout, timeout);
+}
+
+/**
+ * netdev_set_gro_flush_timeout - set gro_flush_timeout for all NAPIs of a netdev
+ * @netdev: the net_device for which all NAPIs will have their gro_flush_timeout set
+ * @timeout: the timeout value to set
+ */
+static inline void netdev_set_gro_flush_timeout(struct net_device *netdev,
+ unsigned long timeout)
+{
+ struct napi_struct *napi;
+
+ WRITE_ONCE(netdev->gro_flush_timeout, timeout);
+ list_for_each_entry(napi, &netdev->napi_list, dev_list)
+ napi_set_gro_flush_timeout(napi, timeout);
+}
+
int rps_cpumask_housekeeping(struct cpumask *mask);
#if defined(CONFIG_DEBUG_NET) && defined(CONFIG_BPF_SYSCALL)
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 0a0bbbfb39b4..daa32b5a6623 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -409,7 +409,7 @@ NETDEVICE_SHOW_RW(tx_queue_len, fmt_dec);
static int change_gro_flush_timeout(struct net_device *dev, unsigned long val)
{
- WRITE_ONCE(dev->gro_flush_timeout, val);
+ netdev_set_gro_flush_timeout(dev, val);
return 0;
}
diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index f1e505ad069f..68ec8265567d 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -161,6 +161,7 @@ netdev_nl_napi_fill_one(struct sk_buff *rsp, struct napi_struct *napi,
const struct genl_info *info)
{
int napi_defer_hard_irqs;
+ unsigned long gro_flush_timeout;
void *hdr;
pid_t pid;
@@ -196,6 +197,10 @@ netdev_nl_napi_fill_one(struct sk_buff *rsp, struct napi_struct *napi,
if (nla_put_s32(rsp, NETDEV_A_NAPI_DEFER_HARD_IRQS, napi_defer_hard_irqs))
goto nla_put_failure;
+ gro_flush_timeout = napi_get_gro_flush_timeout(napi);
+ if (nla_put_uint(rsp, NETDEV_A_NAPI_GRO_FLUSH_TIMEOUT, gro_flush_timeout))
+ goto nla_put_failure;
+
genlmsg_end(rsp, hdr);
return 0;
diff --git a/tools/include/uapi/linux/netdev.h b/tools/include/uapi/linux/netdev.h
index 43bb1aad9611..b088a34e9254 100644
--- a/tools/include/uapi/linux/netdev.h
+++ b/tools/include/uapi/linux/netdev.h
@@ -122,6 +122,7 @@ enum {
NETDEV_A_NAPI_IRQ,
NETDEV_A_NAPI_PID,
NETDEV_A_NAPI_DEFER_HARD_IRQS,
+ NETDEV_A_NAPI_GRO_FLUSH_TIMEOUT,
__NETDEV_A_NAPI_MAX,
NETDEV_A_NAPI_MAX = (__NETDEV_A_NAPI_MAX - 1)
--
2.25.1