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netdevsim: add NAPI support

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Add NAPI support to netdevim, similar to veth.

* Add a nsim_rq rx queue structure to hold a NAPI instance and a skb
  queue.
* During xmit, store the skb in the peer skb queue and schedule NAPI.
* During napi_poll(), drain the skb queue and pass up the stack.
* Add assoc between rxq and NAPI instance using netif_queue_set_napi().

Signed-off-by: David Wei <dw@davidwei.uk>
Link: https://lore.kernel.org/r/20240507163228.2066817-2-dw@davidwei.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
David Wei 2024-05-07 09:32:27 -07:00 committed by Jakub Kicinski
parent 1d0dc857b5
commit 3762ec05a9
2 changed files with 205 additions and 12 deletions
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209
drivers/net/netdevsim/netdev.c
View File

@ -28,11 +28,33 @@
#include "netdevsim.h"
#define NSIM_RING_SIZE 256
static int nsim_napi_rx(struct nsim_rq *rq, struct sk_buff *skb)
{
if (skb_queue_len(&rq->skb_queue) > NSIM_RING_SIZE) {
dev_kfree_skb_any(skb);
return NET_RX_DROP;
}
skb_queue_tail(&rq->skb_queue, skb);
return NET_RX_SUCCESS;
}
static int nsim_forward_skb(struct net_device *dev, struct sk_buff *skb,
struct nsim_rq *rq)
{
return __dev_forward_skb(dev, skb) ?: nsim_napi_rx(rq, skb);
}
static netdev_tx_t nsim_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct netdevsim *ns = netdev_priv(dev);
struct net_device *peer_dev;
unsigned int len = skb->len;
struct netdevsim *peer_ns;
struct nsim_rq *rq;
int rxq;
rcu_read_lock();
if (!nsim_ipsec_tx(ns, skb))
@ -42,10 +64,18 @@ static netdev_tx_t nsim_start_xmit(struct sk_buff *skb, struct net_device *dev)
if (!peer_ns)
goto out_drop_free;
peer_dev = peer_ns->netdev;
rxq = skb_get_queue_mapping(skb);
if (rxq >= peer_dev->num_rx_queues)
rxq = rxq % peer_dev->num_rx_queues;
rq = &peer_ns->rq[rxq];
skb_tx_timestamp(skb);
if (unlikely(dev_forward_skb(peer_ns->netdev, skb) == NET_RX_DROP))
if (unlikely(nsim_forward_skb(peer_dev, skb, rq) == NET_RX_DROP))
goto out_drop_cnt;
napi_schedule(&rq->napi);
rcu_read_unlock();
u64_stats_update_begin(&ns->syncp);
ns->tx_packets++;
@ -300,25 +330,146 @@ static int nsim_get_iflink(const struct net_device *dev)
return iflink;
}
static int nsim_rcv(struct nsim_rq *rq, int budget)
{
struct sk_buff *skb;
int i;
for (i = 0; i < budget; i++) {
if (skb_queue_empty(&rq->skb_queue))
break;
skb = skb_dequeue(&rq->skb_queue);
netif_receive_skb(skb);
}
return i;
}
static int nsim_poll(struct napi_struct *napi, int budget)
{
struct nsim_rq *rq = container_of(napi, struct nsim_rq, napi);
int done;
done = nsim_rcv(rq, budget);
napi_complete(napi);
return done;
}
static int nsim_create_page_pool(struct nsim_rq *rq)
{
struct page_pool_params p = {
.order = 0,
.pool_size = NSIM_RING_SIZE,
.nid = NUMA_NO_NODE,
.dev = &rq->napi.dev->dev,
.napi = &rq->napi,
.dma_dir = DMA_BIDIRECTIONAL,
.netdev = rq->napi.dev,
};
rq->page_pool = page_pool_create(&p);
if (IS_ERR(rq->page_pool)) {
int err = PTR_ERR(rq->page_pool);
rq->page_pool = NULL;
return err;
}
return 0;
}
static int nsim_init_napi(struct netdevsim *ns)
{
struct net_device *dev = ns->netdev;
struct nsim_rq *rq;
int err, i;
for (i = 0; i < dev->num_rx_queues; i++) {
rq = &ns->rq[i];
netif_napi_add(dev, &rq->napi, nsim_poll);
}
for (i = 0; i < dev->num_rx_queues; i++) {
rq = &ns->rq[i];
err = nsim_create_page_pool(rq);
if (err)
goto err_pp_destroy;
}
return 0;
err_pp_destroy:
while (i--) {
page_pool_destroy(ns->rq[i].page_pool);
ns->rq[i].page_pool = NULL;
}
for (i = 0; i < dev->num_rx_queues; i++)
__netif_napi_del(&ns->rq[i].napi);
return err;
}
static void nsim_enable_napi(struct netdevsim *ns)
{
struct net_device *dev = ns->netdev;
int i;
for (i = 0; i < dev->num_rx_queues; i++) {
struct nsim_rq *rq = &ns->rq[i];
netif_queue_set_napi(dev, i, NETDEV_QUEUE_TYPE_RX, &rq->napi);
napi_enable(&rq->napi);
}
}
static int nsim_open(struct net_device *dev)
{
struct netdevsim *ns = netdev_priv(dev);
struct page_pool_params pp = { 0 };
int err;
pp.pool_size = 128;
pp.dev = &dev->dev;
pp.dma_dir = DMA_BIDIRECTIONAL;
pp.netdev = dev;
err = nsim_init_napi(ns);
if (err)
return err;
ns->pp = page_pool_create(&pp);
return PTR_ERR_OR_ZERO(ns->pp);
nsim_enable_napi(ns);
return 0;
}
static void nsim_del_napi(struct netdevsim *ns)
{
struct net_device *dev = ns->netdev;
int i;
for (i = 0; i < dev->num_rx_queues; i++) {
struct nsim_rq *rq = &ns->rq[i];
napi_disable(&rq->napi);
__netif_napi_del(&rq->napi);
}
synchronize_net();
for (i = 0; i < dev->num_rx_queues; i++) {
page_pool_destroy(ns->rq[i].page_pool);
ns->rq[i].page_pool = NULL;
}
}
static int nsim_stop(struct net_device *dev)
{
struct netdevsim *ns = netdev_priv(dev);
struct netdevsim *peer;
page_pool_destroy(ns->pp);
netif_carrier_off(dev);
peer = rtnl_dereference(ns->peer);
if (peer)
netif_carrier_off(peer->netdev);
nsim_del_napi(ns);
return 0;
}
@ -437,7 +588,7 @@ nsim_pp_hold_write(struct file *file, const char __user *data,
if (!netif_running(ns->netdev) && val) {
ret = -ENETDOWN;
} else if (val) {
ns->page = page_pool_dev_alloc_pages(ns->pp);
ns->page = page_pool_dev_alloc_pages(ns->rq[0].page_pool);
if (!ns->page)
ret = -ENOMEM;
} else {
@ -477,6 +628,35 @@ static void nsim_setup(struct net_device *dev)
dev->xdp_features = NETDEV_XDP_ACT_HW_OFFLOAD;
}
static int nsim_queue_init(struct netdevsim *ns)
{
struct net_device *dev = ns->netdev;
int i;
ns->rq = kvcalloc(dev->num_rx_queues, sizeof(*ns->rq),
GFP_KERNEL_ACCOUNT | __GFP_RETRY_MAYFAIL);
if (!ns->rq)
return -ENOMEM;
for (i = 0; i < dev->num_rx_queues; i++)
skb_queue_head_init(&ns->rq[i].skb_queue);
return 0;
}
static void nsim_queue_free(struct netdevsim *ns)
{
struct net_device *dev = ns->netdev;
int i;
for (i = 0; i < dev->num_rx_queues; i++)
skb_queue_purge_reason(&ns->rq[i].skb_queue,
SKB_DROP_REASON_QUEUE_PURGE);
kvfree(ns->rq);
ns->rq = NULL;
}
static int nsim_init_netdevsim(struct netdevsim *ns)
{
struct mock_phc *phc;
@ -495,10 +675,14 @@ static int nsim_init_netdevsim(struct netdevsim *ns)
goto err_phc_destroy;
rtnl_lock();
err = nsim_bpf_init(ns);
err = nsim_queue_init(ns);
if (err)
goto err_utn_destroy;
err = nsim_bpf_init(ns);
if (err)
goto err_rq_destroy;
nsim_macsec_init(ns);
nsim_ipsec_init(ns);
@ -512,6 +696,8 @@ err_ipsec_teardown:
nsim_ipsec_teardown(ns);
nsim_macsec_teardown(ns);
nsim_bpf_uninit(ns);
err_rq_destroy:
nsim_queue_free(ns);
err_utn_destroy:
rtnl_unlock();
nsim_udp_tunnels_info_destroy(ns->netdev);
@ -593,6 +779,7 @@ void nsim_destroy(struct netdevsim *ns)
nsim_macsec_teardown(ns);
nsim_ipsec_teardown(ns);
nsim_bpf_uninit(ns);
nsim_queue_free(ns);
}
rtnl_unlock();
if (nsim_dev_port_is_pf(ns->nsim_dev_port))

8
drivers/net/netdevsim/netdevsim.h
View File

@ -90,11 +90,18 @@ struct nsim_ethtool {
struct ethtool_fecparam fec;
};
struct nsim_rq {
struct napi_struct napi;
struct sk_buff_head skb_queue;
struct page_pool *page_pool;
};
struct netdevsim {
struct net_device *netdev;
struct nsim_dev *nsim_dev;
struct nsim_dev_port *nsim_dev_port;
struct mock_phc *phc;
struct nsim_rq *rq;
u64 tx_packets;
u64 tx_bytes;
@ -125,7 +132,6 @@ struct netdevsim {
struct debugfs_u32_array dfs_ports[2];
} udp_ports;
struct page_pool *pp;
struct page *page;
struct dentry *pp_dfs;