Add a persistent NAPI config area for NAPI configuration to the core.
Drivers opt-in to setting the persistent config for a NAPI by passing an
index when calling netif_napi_add_config.
napi_config is allocated in alloc_netdev_mqs, freed in free_netdev
(after the NAPIs are deleted).
Drivers which call netif_napi_add_config will have persistent per-NAPI
settings: NAPI IDs, gro_flush_timeout, and defer_hard_irq settings.
Per-NAPI settings are saved in napi_disable and restored in napi_enable.
Co-developed-by: Martin Karsten <mkarsten@uwaterloo.ca>
Signed-off-by: Martin Karsten <mkarsten@uwaterloo.ca>
Signed-off-by: Joe Damato <jdamato@fastly.com>
---
.../networking/net_cachelines/net_device.rst | 1 +
include/linux/netdevice.h | 36 ++++++++-
net/core/dev.c | 79 +++++++++++++++++--
net/core/dev.h | 12 +++
4 files changed, 118 insertions(+), 10 deletions(-)
diff --git a/Documentation/networking/net_cachelines/net_device.rst b/Documentation/networking/net_cachelines/net_device.rst
index 3ab663b6cf16..9d86720cb722 100644
--- a/Documentation/networking/net_cachelines/net_device.rst
+++ b/Documentation/networking/net_cachelines/net_device.rst
@@ -183,5 +183,6 @@ struct_dpll_pin* dpll_pin
struct hlist_head page_pools
struct dim_irq_moder* irq_moder
u64 max_pacing_offload_horizon
+struct_napi_config* napi_config
unsigned_long gro_flush_timeout
u32 napi_defer_hard_irqs
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 4239a4a9d295..b65a901ab4e7 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -342,6 +342,15 @@ struct gro_list {
*/
#define GRO_HASH_BUCKETS 8
+/*
+ * Structure for per-NAPI config
+ */
+struct napi_config {
+ u64 gro_flush_timeout;
+ u32 defer_hard_irqs;
+ unsigned int napi_id;
+};
+
/*
* Structure for NAPI scheduling similar to tasklet but with weighting
*/
@@ -379,6 +388,8 @@ struct napi_struct {
struct list_head dev_list;
struct hlist_node napi_hash_node;
int irq;
+ int index;
+ struct napi_config *config;
};
enum {
@@ -1860,9 +1871,6 @@ enum netdev_reg_state {
* allocated at register_netdev() time
* @real_num_rx_queues: Number of RX queues currently active in device
* @xdp_prog: XDP sockets filter program pointer
- * @gro_flush_timeout: timeout for GRO layer in NAPI
- * @napi_defer_hard_irqs: If not zero, provides a counter that would
- * allow to avoid NIC hard IRQ, on busy queues.
*
* @rx_handler: handler for received packets
* @rx_handler_data: XXX: need comments on this one
@@ -2012,6 +2020,11 @@ enum netdev_reg_state {
* where the clock is recovered.
*
* @max_pacing_offload_horizon: max EDT offload horizon in nsec.
+ * @napi_config: An array of napi_config structures containing per-NAPI
+ * settings.
+ * @gro_flush_timeout: timeout for GRO layer in NAPI
+ * @napi_defer_hard_irqs: If not zero, provides a counter that would
+ * allow to avoid NIC hard IRQ, on busy queues.
*
* FIXME: cleanup struct net_device such that network protocol info
* moves out.
@@ -2405,6 +2418,7 @@ struct net_device {
struct dim_irq_moder *irq_moder;
u64 max_pacing_offload_horizon;
+ struct napi_config *napi_config;
unsigned long gro_flush_timeout;
u32 napi_defer_hard_irqs;
@@ -2657,6 +2671,22 @@ netif_napi_add_tx_weight(struct net_device *dev,
netif_napi_add_weight(dev, napi, poll, weight);
}
+/**
+ * netif_napi_add_config - initialize a NAPI context with persistent config
+ * @dev: network device
+ * @napi: NAPI context
+ * @poll: polling function
+ * @index: the NAPI index
+ */
+static inline void
+netif_napi_add_config(struct net_device *dev, struct napi_struct *napi,
+ int (*poll)(struct napi_struct *, int), int index)
+{
+ napi->index = index;
+ napi->config = &dev->napi_config[index];
+ netif_napi_add_weight(dev, napi, poll, NAPI_POLL_WEIGHT);
+}
+
/**
* netif_napi_add_tx() - initialize a NAPI context to be used for Tx only
* @dev: network device
diff --git a/net/core/dev.c b/net/core/dev.c
index fca2295f4d95..bd87232f7b37 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6503,6 +6503,22 @@ EXPORT_SYMBOL(napi_busy_loop);
#endif /* CONFIG_NET_RX_BUSY_POLL */
+static void __napi_hash_add_with_id(struct napi_struct *napi,
+ unsigned int napi_id)
+{
+ napi->napi_id = napi_id;
+ hlist_add_head_rcu(&napi->napi_hash_node,
+ &napi_hash[napi->napi_id % HASH_SIZE(napi_hash)]);
+}
+
+static void napi_hash_add_with_id(struct napi_struct *napi,
+ unsigned int napi_id)
+{
+ spin_lock(&napi_hash_lock);
+ __napi_hash_add_with_id(napi, napi_id);
+ spin_unlock(&napi_hash_lock);
+}
+
static void napi_hash_add(struct napi_struct *napi)
{
if (test_bit(NAPI_STATE_NO_BUSY_POLL, &napi->state))
@@ -6515,10 +6531,8 @@ static void napi_hash_add(struct napi_struct *napi)
if (unlikely(++napi_gen_id < MIN_NAPI_ID))
napi_gen_id = MIN_NAPI_ID;
} while (napi_by_id(napi_gen_id));
- napi->napi_id = napi_gen_id;
- hlist_add_head_rcu(&napi->napi_hash_node,
- &napi_hash[napi->napi_id % HASH_SIZE(napi_hash)]);
+ __napi_hash_add_with_id(napi, napi_gen_id);
spin_unlock(&napi_hash_lock);
}
@@ -6641,6 +6655,28 @@ void netif_queue_set_napi(struct net_device *dev, unsigned int queue_index,
}
EXPORT_SYMBOL(netif_queue_set_napi);
+static void napi_restore_config(struct napi_struct *n)
+{
+ n->defer_hard_irqs = n->config->defer_hard_irqs;
+ n->gro_flush_timeout = n->config->gro_flush_timeout;
+ /* a NAPI ID might be stored in the config, if so use it. if not, use
+ * napi_hash_add to generate one for us. It will be saved to the config
+ * in napi_disable.
+ */
+ if (n->config->napi_id)
+ napi_hash_add_with_id(n, n->config->napi_id);
+ else
+ napi_hash_add(n);
+}
+
+static void napi_save_config(struct napi_struct *n)
+{
+ n->config->defer_hard_irqs = n->defer_hard_irqs;
+ n->config->gro_flush_timeout = n->gro_flush_timeout;
+ n->config->napi_id = n->napi_id;
+ napi_hash_del(n);
+}
+
void netif_napi_add_weight(struct net_device *dev, struct napi_struct *napi,
int (*poll)(struct napi_struct *, int), int weight)
{
@@ -6651,8 +6687,6 @@ void netif_napi_add_weight(struct net_device *dev, struct napi_struct *napi,
INIT_HLIST_NODE(&napi->napi_hash_node);
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);
@@ -6670,7 +6704,13 @@ void netif_napi_add_weight(struct net_device *dev, struct napi_struct *napi,
set_bit(NAPI_STATE_SCHED, &napi->state);
set_bit(NAPI_STATE_NPSVC, &napi->state);
list_add_rcu(&napi->dev_list, &dev->napi_list);
- napi_hash_add(napi);
+
+ /* default settings from sysfs are applied to all NAPIs. any per-NAPI
+ * configuration will be loaded in napi_enable
+ */
+ 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));
+
napi_get_frags_check(napi);
/* Create kthread for this napi if dev->threaded is set.
* Clear dev->threaded if kthread creation failed so that
@@ -6702,6 +6742,11 @@ void napi_disable(struct napi_struct *n)
hrtimer_cancel(&n->timer);
+ if (n->config)
+ napi_save_config(n);
+ else
+ napi_hash_del(n);
+
clear_bit(NAPI_STATE_DISABLE, &n->state);
}
EXPORT_SYMBOL(napi_disable);
@@ -6717,6 +6762,11 @@ void napi_enable(struct napi_struct *n)
{
unsigned long new, val = READ_ONCE(n->state);
+ if (n->config)
+ napi_restore_config(n);
+ else
+ napi_hash_add(n);
+
do {
BUG_ON(!test_bit(NAPI_STATE_SCHED, &val));
@@ -6746,7 +6796,11 @@ void __netif_napi_del(struct napi_struct *napi)
if (!test_and_clear_bit(NAPI_STATE_LISTED, &napi->state))
return;
- napi_hash_del(napi);
+ if (napi->config) {
+ napi->index = -1;
+ napi->config = NULL;
+ }
+
list_del_rcu(&napi->dev_list);
napi_free_frags(napi);
@@ -11083,6 +11137,8 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
unsigned int txqs, unsigned int rxqs)
{
struct net_device *dev;
+ size_t napi_config_sz;
+ unsigned int maxqs;
BUG_ON(strlen(name) >= sizeof(dev->name));
@@ -11096,6 +11152,8 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
return NULL;
}
+ maxqs = max(txqs, rxqs);
+
dev = kvzalloc(struct_size(dev, priv, sizeof_priv),
GFP_KERNEL_ACCOUNT | __GFP_RETRY_MAYFAIL);
if (!dev)
@@ -11170,6 +11228,11 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
if (!dev->ethtool)
goto free_all;
+ napi_config_sz = array_size(maxqs, sizeof(*dev->napi_config));
+ dev->napi_config = kvzalloc(napi_config_sz, GFP_KERNEL_ACCOUNT);
+ if (!dev->napi_config)
+ goto free_all;
+
strscpy(dev->name, name);
dev->name_assign_type = name_assign_type;
dev->group = INIT_NETDEV_GROUP;
@@ -11231,6 +11294,8 @@ void free_netdev(struct net_device *dev)
list_for_each_entry_safe(p, n, &dev->napi_list, dev_list)
netif_napi_del(p);
+ kvfree(dev->napi_config);
+
ref_tracker_dir_exit(&dev->refcnt_tracker);
#ifdef CONFIG_PCPU_DEV_REFCNT
free_percpu(dev->pcpu_refcnt);
diff --git a/net/core/dev.h b/net/core/dev.h
index 26e598aa56c3..f22cb532de7a 100644
--- a/net/core/dev.h
+++ b/net/core/dev.h
@@ -167,11 +167,17 @@ static inline void napi_set_defer_hard_irqs(struct napi_struct *n, u32 defer)
static inline void netdev_set_defer_hard_irqs(struct net_device *netdev,
u32 defer)
{
+ unsigned int count = max(netdev->num_rx_queues,
+ netdev->num_tx_queues);
struct napi_struct *napi;
+ int i;
WRITE_ONCE(netdev->napi_defer_hard_irqs, defer);
list_for_each_entry(napi, &netdev->napi_list, dev_list)
napi_set_defer_hard_irqs(napi, defer);
+
+ for (i = 0; i < count; i++)
+ netdev->napi_config[i].defer_hard_irqs = defer;
}
/**
@@ -207,11 +213,17 @@ static inline void napi_set_gro_flush_timeout(struct napi_struct *n,
static inline void netdev_set_gro_flush_timeout(struct net_device *netdev,
unsigned long timeout)
{
+ unsigned int count = max(netdev->num_rx_queues,
+ netdev->num_tx_queues);
struct napi_struct *napi;
+ int i;
WRITE_ONCE(netdev->gro_flush_timeout, timeout);
list_for_each_entry(napi, &netdev->napi_list, dev_list)
napi_set_gro_flush_timeout(napi, timeout);
+
+ for (i = 0; i < count; i++)
+ netdev->napi_config[i].gro_flush_timeout = timeout;
}
int rps_cpumask_housekeeping(struct cpumask *mask);
--
2.34.1On Wed, Oct 9, 2024 at 2:56 AM Joe Damato <jdamato@fastly.com> wrote:
>
> Add a persistent NAPI config area for NAPI configuration to the core.
> Drivers opt-in to setting the persistent config for a NAPI by passing an
> index when calling netif_napi_add_config.
>
> napi_config is allocated in alloc_netdev_mqs, freed in free_netdev
> (after the NAPIs are deleted).
>
> Drivers which call netif_napi_add_config will have persistent per-NAPI
> settings: NAPI IDs, gro_flush_timeout, and defer_hard_irq settings.
>
> Per-NAPI settings are saved in napi_disable and restored in napi_enable.
>
> Co-developed-by: Martin Karsten <mkarsten@uwaterloo.ca>
> Signed-off-by: Martin Karsten <mkarsten@uwaterloo.ca>
> Signed-off-by: Joe Damato <jdamato@fastly.com>
> ---
> .../networking/net_cachelines/net_device.rst | 1 +
> include/linux/netdevice.h | 36 ++++++++-
> net/core/dev.c | 79 +++++++++++++++++--
> net/core/dev.h | 12 +++
> 4 files changed, 118 insertions(+), 10 deletions(-)
>
> diff --git a/Documentation/networking/net_cachelines/net_device.rst b/Documentation/networking/net_cachelines/net_device.rst
> index 3ab663b6cf16..9d86720cb722 100644
> --- a/Documentation/networking/net_cachelines/net_device.rst
> +++ b/Documentation/networking/net_cachelines/net_device.rst
> @@ -183,5 +183,6 @@ struct_dpll_pin* dpll_pin
> struct hlist_head page_pools
> struct dim_irq_moder* irq_moder
> u64 max_pacing_offload_horizon
> +struct_napi_config* napi_config
> unsigned_long gro_flush_timeout
> u32 napi_defer_hard_irqs
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index 4239a4a9d295..b65a901ab4e7 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -342,6 +342,15 @@ struct gro_list {
> */
> #define GRO_HASH_BUCKETS 8
>
> +/*
> + * Structure for per-NAPI config
> + */
> +struct napi_config {
> + u64 gro_flush_timeout;
> + u32 defer_hard_irqs;
> + unsigned int napi_id;
> +};
> +
> /*
> * Structure for NAPI scheduling similar to tasklet but with weighting
> */
> @@ -379,6 +388,8 @@ struct napi_struct {
> struct list_head dev_list;
> struct hlist_node napi_hash_node;
> int irq;
> + int index;
> + struct napi_config *config;
> };
>
> enum {
> @@ -1860,9 +1871,6 @@ enum netdev_reg_state {
> * allocated at register_netdev() time
> * @real_num_rx_queues: Number of RX queues currently active in device
> * @xdp_prog: XDP sockets filter program pointer
> - * @gro_flush_timeout: timeout for GRO layer in NAPI
> - * @napi_defer_hard_irqs: If not zero, provides a counter that would
> - * allow to avoid NIC hard IRQ, on busy queues.
> *
> * @rx_handler: handler for received packets
> * @rx_handler_data: XXX: need comments on this one
> @@ -2012,6 +2020,11 @@ enum netdev_reg_state {
> * where the clock is recovered.
> *
> * @max_pacing_offload_horizon: max EDT offload horizon in nsec.
> + * @napi_config: An array of napi_config structures containing per-NAPI
> + * settings.
> + * @gro_flush_timeout: timeout for GRO layer in NAPI
> + * @napi_defer_hard_irqs: If not zero, provides a counter that would
> + * allow to avoid NIC hard IRQ, on busy queues.
> *
> * FIXME: cleanup struct net_device such that network protocol info
> * moves out.
> @@ -2405,6 +2418,7 @@ struct net_device {
> struct dim_irq_moder *irq_moder;
>
> u64 max_pacing_offload_horizon;
> + struct napi_config *napi_config;
> unsigned long gro_flush_timeout;
> u32 napi_defer_hard_irqs;
>
> @@ -2657,6 +2671,22 @@ netif_napi_add_tx_weight(struct net_device *dev,
> netif_napi_add_weight(dev, napi, poll, weight);
> }
>
> +/**
> + * netif_napi_add_config - initialize a NAPI context with persistent config
> + * @dev: network device
> + * @napi: NAPI context
> + * @poll: polling function
> + * @index: the NAPI index
> + */
> +static inline void
> +netif_napi_add_config(struct net_device *dev, struct napi_struct *napi,
> + int (*poll)(struct napi_struct *, int), int index)
> +{
> + napi->index = index;
> + napi->config = &dev->napi_config[index];
> + netif_napi_add_weight(dev, napi, poll, NAPI_POLL_WEIGHT);
> +}
> +
> /**
> * netif_napi_add_tx() - initialize a NAPI context to be used for Tx only
> * @dev: network device
> diff --git a/net/core/dev.c b/net/core/dev.c
> index fca2295f4d95..bd87232f7b37 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -6503,6 +6503,22 @@ EXPORT_SYMBOL(napi_busy_loop);
>
> #endif /* CONFIG_NET_RX_BUSY_POLL */
>
> +static void __napi_hash_add_with_id(struct napi_struct *napi,
> + unsigned int napi_id)
> +{
> + napi->napi_id = napi_id;
> + hlist_add_head_rcu(&napi->napi_hash_node,
> + &napi_hash[napi->napi_id % HASH_SIZE(napi_hash)]);
> +}
> +
> +static void napi_hash_add_with_id(struct napi_struct *napi,
> + unsigned int napi_id)
> +{
> + spin_lock(&napi_hash_lock);
> + __napi_hash_add_with_id(napi, napi_id);
Hmmm... there is no check if 'napi_id' is already used and hashed.
I would add
WARN_ON_ONCE(napi_by_id(napi_id));
> + spin_unlock(&napi_hash_lock);
> +}
> +
> static void napi_hash_add(struct napi_struct *napi)
> {
> if (test_bit(NAPI_STATE_NO_BUSY_POLL, &napi->state))
> @@ -6515,10 +6531,8 @@ static void napi_hash_add(struct napi_struct *napi)
> if (unlikely(++napi_gen_id < MIN_NAPI_ID))
> napi_gen_id = MIN_NAPI_ID;
> } while (napi_by_id(napi_gen_id));
> - napi->napi_id = napi_gen_id;
>
> - hlist_add_head_rcu(&napi->napi_hash_node,
> - &napi_hash[napi->napi_id % HASH_SIZE(napi_hash)]);
> + __napi_hash_add_with_id(napi, napi_gen_id);
>
> spin_unlock(&napi_hash_lock);
> }
>
On Thu, Oct 10, 2024 at 06:20:57AM +0200, Eric Dumazet wrote:
> On Wed, Oct 9, 2024 at 2:56 AM Joe Damato <jdamato@fastly.com> wrote:
[...]
> > +
> > +static void napi_hash_add_with_id(struct napi_struct *napi,
> > + unsigned int napi_id)
> > +{
> > + spin_lock(&napi_hash_lock);
> > + __napi_hash_add_with_id(napi, napi_id);
>
> Hmmm... there is no check if 'napi_id' is already used and hashed.
>
> I would add
>
> WARN_ON_ONCE(napi_by_id(napi_id));
Thanks for the careful review, Eric.
I agree that adding this is a good idea and I will do so for the v6.
Jakub: I hope that it's OK if I retain your Reviewed-by tag as the
change Eric suggested is a minor one?
If you'd prefer I drop your Reviewed-by from this one, please let me
know.
© 2016 - 2024 Red Hat, Inc.