Jason Wang
2016-Jun-30 03:52 UTC
[PATCH net-next V3 0/6] switch to use tx skb array in tun
Hi all: This series tries to switch to use skb array in tun. This is used to eliminate the spinlock contention between producer and consumer. The conversion was straightforward: just introdce a tx skb array and use it instead of sk_receive_queue. A minor issue is to keep the tx_queue_len behaviour, since tun used to use it for the length of sk_receive_queue. This is done through: - add the ability to resize multiple rings at once to avoid handling partial resize failure for mutiple rings. - add the support for zero length ring. - introduce a notifier which was triggered when tx_queue_len was changed for a netdev. - resize all queues during the tx_queue_len changing. Tests shows about 15% improvement on guest rx pps: Before: ~1300000pps After : ~1500000pps Changes from V2: - add multiple rings resizing support for ptr_ring/skb_array - add zero length ring support - introdce a NETDEV_CHANGE_TX_QUEUE_LEN - drop new flags Changes from V1: - switch to use skb array instead of a customized circular buffer - add non-blocking support - rename .peek to .peek_len - drop lockless peeking since test show very minor improvement Jason Wang (5): ptr_ring: support zero length ring skb_array: minor tweak skb_array: add wrappers for resizing net: introduce NETDEV_CHANGE_TX_QUEUE_LEN tun: switch to use skb array for tx Michael S. Tsirkin (1): ptr_ring: support resizing multiple queues drivers/net/tun.c | 138 ++++++++++++++++++++++++++++++++++++--- drivers/vhost/net.c | 16 ++++- include/linux/net.h | 1 + include/linux/netdevice.h | 1 + include/linux/ptr_ring.h | 77 ++++++++++++++++++---- include/linux/skb_array.h | 13 +++- net/core/net-sysfs.c | 15 ++++- tools/virtio/ringtest/ptr_ring.c | 5 ++ 8 files changed, 243 insertions(+), 23 deletions(-) -- 2.7.4
Jason Wang
2016-Jun-30 03:52 UTC
[PATCH net-next V3 1/6] ptr_ring: support zero length ring
Sometimes, we need zero length ring. But current code will crash since
we don't do any check before accessing the ring. This patch fixes this.
Signed-off-by: Jason Wang <jasowang at redhat.com>
---
include/linux/ptr_ring.h | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h
index 562a65e..d78b8b8 100644
--- a/include/linux/ptr_ring.h
+++ b/include/linux/ptr_ring.h
@@ -102,7 +102,7 @@ static inline bool ptr_ring_full_bh(struct ptr_ring *r)
*/
static inline int __ptr_ring_produce(struct ptr_ring *r, void *ptr)
{
- if (r->queue[r->producer])
+ if (unlikely(!r->size) || r->queue[r->producer])
return -ENOSPC;
r->queue[r->producer++] = ptr;
@@ -164,7 +164,9 @@ static inline int ptr_ring_produce_bh(struct ptr_ring *r,
void *ptr)
*/
static inline void *__ptr_ring_peek(struct ptr_ring *r)
{
- return r->queue[r->consumer];
+ if (likely(r->size))
+ return r->queue[r->consumer];
+ return NULL;
}
/* Note: callers invoking this in a loop must use a compiler barrier,
--
2.7.4
Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
Signed-off-by: Jason Wang <jasowang at redhat.com>
---
include/linux/skb_array.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/skb_array.h b/include/linux/skb_array.h
index 678bfbf..2dd0d1e 100644
--- a/include/linux/skb_array.h
+++ b/include/linux/skb_array.h
@@ -151,12 +151,12 @@ static inline int skb_array_init(struct skb_array *a, int
size, gfp_t gfp)
return ptr_ring_init(&a->ring, size, gfp);
}
-void __skb_array_destroy_skb(void *ptr)
+static void __skb_array_destroy_skb(void *ptr)
{
kfree_skb(ptr);
}
-int skb_array_resize(struct skb_array *a, int size, gfp_t gfp)
+static inline int skb_array_resize(struct skb_array *a, int size, gfp_t gfp)
{
return ptr_ring_resize(&a->ring, size, gfp, __skb_array_destroy_skb);
}
--
2.7.4
Jason Wang
2016-Jun-30 03:52 UTC
[PATCH net-next V3 3/6] ptr_ring: support resizing multiple queues
From: "Michael S. Tsirkin" <mst at redhat.com>
Sometimes, we need support resizing multiple queues at once. This is
because it was not easy to recover to recover from a partial failure
of multiple queues resizing.
Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
Signed-off-by: Jason Wang <jasowang at redhat.com>
---
include/linux/ptr_ring.h | 71 +++++++++++++++++++++++++++++++++++-----
tools/virtio/ringtest/ptr_ring.c | 5 +++
2 files changed, 67 insertions(+), 9 deletions(-)
diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h
index d78b8b8..2052011 100644
--- a/include/linux/ptr_ring.h
+++ b/include/linux/ptr_ring.h
@@ -349,20 +349,14 @@ static inline int ptr_ring_init(struct ptr_ring *r, int
size, gfp_t gfp)
return 0;
}
-static inline int ptr_ring_resize(struct ptr_ring *r, int size, gfp_t gfp,
- void (*destroy)(void *))
+static inline void **__ptr_ring_swap_queue(struct ptr_ring *r, void **queue,
+ int size, gfp_t gfp,
+ void (*destroy)(void *))
{
- unsigned long flags;
int producer = 0;
- void **queue = __ptr_ring_init_queue_alloc(size, gfp);
void **old;
void *ptr;
- if (!queue)
- return -ENOMEM;
-
- spin_lock_irqsave(&(r)->producer_lock, flags);
-
while ((ptr = ptr_ring_consume(r)))
if (producer < size)
queue[producer++] = ptr;
@@ -375,6 +369,23 @@ static inline int ptr_ring_resize(struct ptr_ring *r, int
size, gfp_t gfp,
old = r->queue;
r->queue = queue;
+ return old;
+}
+
+static inline int ptr_ring_resize(struct ptr_ring *r, int size, gfp_t gfp,
+ void (*destroy)(void *))
+{
+ unsigned long flags;
+ void **queue = __ptr_ring_init_queue_alloc(size, gfp);
+ void **old;
+
+ if (!queue)
+ return -ENOMEM;
+
+ spin_lock_irqsave(&(r)->producer_lock, flags);
+
+ old = __ptr_ring_swap_queue(r, queue, size, gfp, destroy);
+
spin_unlock_irqrestore(&(r)->producer_lock, flags);
kfree(old);
@@ -382,6 +393,48 @@ static inline int ptr_ring_resize(struct ptr_ring *r, int
size, gfp_t gfp,
return 0;
}
+static inline int ptr_ring_resize_multiple(struct ptr_ring **rings, int nrings,
+ int size,
+ gfp_t gfp, void (*destroy)(void *))
+{
+ unsigned long flags;
+ void ***queues;
+ int i;
+
+ queues = kmalloc(nrings * sizeof *queues, gfp);
+ if (!queues)
+ goto noqueues;
+
+ for (i = 0; i < nrings; ++i) {
+ queues[i] = __ptr_ring_init_queue_alloc(size, gfp);
+ if (!queues[i])
+ goto nomem;
+ }
+
+ for (i = 0; i < nrings; ++i) {
+ spin_lock_irqsave(&(rings[i])->producer_lock, flags);
+ queues[i] = __ptr_ring_swap_queue(rings[i], queues[i],
+ size, gfp, destroy);
+ spin_unlock_irqrestore(&(rings[i])->producer_lock, flags);
+ }
+
+ for (i = 0; i < nrings; ++i)
+ kfree(queues[i]);
+
+ kfree(queues);
+
+ return 0;
+
+nomem:
+ while (--i >= 0)
+ kfree(queues[i]);
+
+ kfree(queues);
+
+noqueues:
+ return -ENOMEM;
+}
+
static inline void ptr_ring_cleanup(struct ptr_ring *r, void (*destroy)(void
*))
{
void *ptr;
diff --git a/tools/virtio/ringtest/ptr_ring.c b/tools/virtio/ringtest/ptr_ring.c
index 74abd74..68e4f9f 100644
--- a/tools/virtio/ringtest/ptr_ring.c
+++ b/tools/virtio/ringtest/ptr_ring.c
@@ -17,6 +17,11 @@
typedef pthread_spinlock_t spinlock_t;
typedef int gfp_t;
+static void *kmalloc(unsigned size, gfp_t gfp)
+{
+ return memalign(64, size);
+}
+
static void *kzalloc(unsigned size, gfp_t gfp)
{
void *p = memalign(64, size);
--
2.7.4
Jason Wang
2016-Jun-30 03:52 UTC
[PATCH net-next V3 4/6] skb_array: add wrappers for resizing
Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
Signed-off-by: Jason Wang <jasowang at redhat.com>
---
include/linux/skb_array.h | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/include/linux/skb_array.h b/include/linux/skb_array.h
index 2dd0d1e..f4dfade 100644
--- a/include/linux/skb_array.h
+++ b/include/linux/skb_array.h
@@ -161,6 +161,15 @@ static inline int skb_array_resize(struct skb_array *a, int
size, gfp_t gfp)
return ptr_ring_resize(&a->ring, size, gfp, __skb_array_destroy_skb);
}
+static inline int skb_array_resize_multiple(struct skb_array **rings,
+ int nrings, int size, gfp_t gfp)
+{
+ BUILD_BUG_ON(offsetof(struct skb_array, ring));
+ return ptr_ring_resize_multiple((struct ptr_ring **)rings,
+ nrings, size, gfp,
+ __skb_array_destroy_skb);
+}
+
static inline void skb_array_cleanup(struct skb_array *a)
{
ptr_ring_cleanup(&a->ring, __skb_array_destroy_skb);
--
2.7.4
Jason Wang
2016-Jun-30 03:52 UTC
[PATCH net-next V3 5/6] net: introduce NETDEV_CHANGE_TX_QUEUE_LEN
This patch introduces a new event - NETDEV_CHANGE_TX_QUEUE_LEN, this
will be triggered when tx_queue_len. It could be used by net device
who want to do some processing at that time. An example is tun who may
want to resize tx array when tx_queue_len is changed.
Signed-off-by: Jason Wang <jasowang at redhat.com>
---
include/linux/netdevice.h | 1 +
net/core/net-sysfs.c | 15 ++++++++++++++-
2 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index e84d9d2..7dc2ec7 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2237,6 +2237,7 @@ struct netdev_lag_lower_state_info {
#define NETDEV_PRECHANGEUPPER 0x001A
#define NETDEV_CHANGELOWERSTATE 0x001B
#define NETDEV_UDP_TUNNEL_PUSH_INFO 0x001C
+#define NETDEV_CHANGE_TX_QUEUE_LEN 0x001E
int register_netdevice_notifier(struct notifier_block *nb);
int unregister_netdevice_notifier(struct notifier_block *nb);
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 7a0b616..6e4f347 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -322,7 +322,20 @@ NETDEVICE_SHOW_RW(flags, fmt_hex);
static int change_tx_queue_len(struct net_device *dev, unsigned long new_len)
{
- dev->tx_queue_len = new_len;
+ int res, orig_len = dev->tx_queue_len;
+
+ if (new_len != orig_len) {
+ dev->tx_queue_len = new_len;
+ res = call_netdevice_notifiers(NETDEV_CHANGE_TX_QUEUE_LEN, dev);
+ res = notifier_to_errno(res);
+ if (res) {
+ netdev_err(dev,
+ "refused to change device tx_queue_len\n");
+ dev->tx_queue_len = orig_len;
+ return -EFAULT;
+ }
+ }
+
return 0;
}
--
2.7.4
Jason Wang
2016-Jun-30 03:52 UTC
[PATCH net-next V3 6/6] tun: switch to use skb array for tx
We used to queue tx packets in sk_receive_queue, this is less
efficient since it requires spinlocks to synchronize between producer
and consumer.
This patch tries to address this by:
- switch from sk_receive_queue to a skb_array, and resize it when
tx_queue_len was changed.
- introduce a new proto_ops peek_len which was used for peeking the
skb length.
- implement a tun version of peek_len for vhost_net to use and convert
vhost_net to use peek_len if possible.
Pktgen test shows about 15.3% improvement on guest receiving pps for small
buffers:
Before: ~1300000pps
After : ~1500000pps
Signed-off-by: Jason Wang <jasowang at redhat.com>
---
drivers/net/tun.c | 138 +++++++++++++++++++++++++++++++++++++++++++++++++---
drivers/vhost/net.c | 16 +++++-
include/linux/net.h | 1 +
3 files changed, 146 insertions(+), 9 deletions(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 4884802..3be69ea 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -71,6 +71,7 @@
#include <net/sock.h>
#include <linux/seq_file.h>
#include <linux/uio.h>
+#include <linux/skb_array.h>
#include <asm/uaccess.h>
@@ -167,6 +168,7 @@ struct tun_file {
};
struct list_head next;
struct tun_struct *detached;
+ struct skb_array tx_array;
};
struct tun_flow_entry {
@@ -515,7 +517,11 @@ static struct tun_struct *tun_enable_queue(struct tun_file
*tfile)
static void tun_queue_purge(struct tun_file *tfile)
{
- skb_queue_purge(&tfile->sk.sk_receive_queue);
+ struct sk_buff *skb;
+
+ while ((skb = skb_array_consume(&tfile->tx_array)) != NULL)
+ kfree_skb(skb);
+
skb_queue_purge(&tfile->sk.sk_error_queue);
}
@@ -560,6 +566,8 @@ static void __tun_detach(struct tun_file *tfile, bool clean)
tun->dev->reg_state == NETREG_REGISTERED)
unregister_netdevice(tun->dev);
}
+ if (tun)
+ skb_array_cleanup(&tfile->tx_array);
sock_put(&tfile->sk);
}
}
@@ -613,6 +621,7 @@ static void tun_detach_all(struct net_device *dev)
static int tun_attach(struct tun_struct *tun, struct file *file, bool
skip_filter)
{
struct tun_file *tfile = file->private_data;
+ struct net_device *dev = tun->dev;
int err;
err = security_tun_dev_attach(tfile->socket.sk, tun->security);
@@ -642,6 +651,13 @@ static int tun_attach(struct tun_struct *tun, struct file
*file, bool skip_filte
if (!err)
goto out;
}
+
+ if (!tfile->detached &&
+ skb_array_init(&tfile->tx_array, dev->tx_queue_len, GFP_KERNEL))
{
+ err = -ENOMEM;
+ goto out;
+ }
+
tfile->queue_index = tun->numqueues;
tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
rcu_assign_pointer(tfile->tun, tun);
@@ -891,8 +907,8 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct
net_device *dev)
nf_reset(skb);
- /* Enqueue packet */
- skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb);
+ if (skb_array_produce(&tfile->tx_array, skb))
+ goto drop;
/* Notify and wake up reader process */
if (tfile->flags & TUN_FASYNC)
@@ -1107,7 +1123,7 @@ static unsigned int tun_chr_poll(struct file *file,
poll_table *wait)
poll_wait(file, sk_sleep(sk), wait);
- if (!skb_queue_empty(&sk->sk_receive_queue))
+ if (!skb_array_empty(&tfile->tx_array))
mask |= POLLIN | POLLRDNORM;
if (sock_writeable(sk) ||
@@ -1426,22 +1442,61 @@ done:
return total;
}
+static struct sk_buff *tun_ring_recv(struct tun_file *tfile, int noblock,
+ int *err)
+{
+ DECLARE_WAITQUEUE(wait, current);
+ struct sk_buff *skb = NULL;
+
+ skb = skb_array_consume(&tfile->tx_array);
+ if (skb)
+ goto out;
+ if (noblock) {
+ *err = -EAGAIN;
+ goto out;
+ }
+
+ add_wait_queue(&tfile->wq.wait, &wait);
+ current->state = TASK_INTERRUPTIBLE;
+
+ while (1) {
+ skb = skb_array_consume(&tfile->tx_array);
+ if (skb)
+ break;
+ if (signal_pending(current)) {
+ *err = -ERESTARTSYS;
+ break;
+ }
+ if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
+ *err = -EFAULT;
+ break;
+ }
+
+ schedule();
+ };
+
+ current->state = TASK_RUNNING;
+ remove_wait_queue(&tfile->wq.wait, &wait);
+
+out:
+ return skb;
+}
+
static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
struct iov_iter *to,
int noblock)
{
struct sk_buff *skb;
ssize_t ret;
- int peeked, err, off = 0;
+ int err;
tun_debug(KERN_INFO, tun, "tun_do_read\n");
if (!iov_iter_count(to))
return 0;
- /* Read frames from queue */
- skb = __skb_recv_datagram(tfile->socket.sk, noblock ? MSG_DONTWAIT : 0,
- &peeked, &off, &err);
+ /* Read frames from ring */
+ skb = tun_ring_recv(tfile, noblock, &err);
if (!skb)
return err;
@@ -1574,8 +1629,25 @@ out:
return ret;
}
+static int tun_peek_len(struct socket *sock)
+{
+ struct tun_file *tfile = container_of(sock, struct tun_file, socket);
+ struct tun_struct *tun;
+ int ret = 0;
+
+ tun = __tun_get(tfile);
+ if (!tun)
+ return 0;
+
+ ret = skb_array_peek_len(&tfile->tx_array);
+ tun_put(tun);
+
+ return ret;
+}
+
/* Ops structure to mimic raw sockets with tun */
static const struct proto_ops tun_socket_ops = {
+ .peek_len = tun_peek_len,
.sendmsg = tun_sendmsg,
.recvmsg = tun_recvmsg,
};
@@ -2397,6 +2469,53 @@ static const struct ethtool_ops tun_ethtool_ops = {
.get_ts_info = ethtool_op_get_ts_info,
};
+static int tun_queue_resize(struct tun_struct *tun)
+{
+ struct net_device *dev = tun->dev;
+ struct tun_file *tfile;
+ struct skb_array **arrays;
+ int n = tun->numqueues + tun->numdisabled;
+ int ret, i;
+
+ arrays = kmalloc(sizeof *arrays * n, GFP_KERNEL);
+ if (!arrays)
+ return -ENOMEM;
+
+ for (i = 0; i < tun->numqueues; i++) {
+ tfile = rtnl_dereference(tun->tfiles[i]);
+ arrays[i] = &tfile->tx_array;
+ }
+ list_for_each_entry(tfile, &tun->disabled, next)
+ arrays[i++] = &tfile->tx_array;
+
+ ret = skb_array_resize_multiple(arrays, n,
+ dev->tx_queue_len, GFP_KERNEL);
+
+ kfree(arrays);
+ return ret;
+}
+
+static int tun_device_event(struct notifier_block *unused,
+ unsigned long event, void *ptr)
+{
+ struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+ struct tun_struct *tun = netdev_priv(dev);
+
+ switch (event) {
+ case NETDEV_CHANGE_TX_QUEUE_LEN:
+ if (tun_queue_resize(tun))
+ return NOTIFY_BAD;
+ break;
+ default:
+ break;
+ }
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block tun_notifier_block __read_mostly = {
+ .notifier_call = tun_device_event,
+};
static int __init tun_init(void)
{
@@ -2416,6 +2535,8 @@ static int __init tun_init(void)
pr_err("Can't register misc device %d\n", TUN_MINOR);
goto err_misc;
}
+
+ register_netdevice_notifier(&tun_notifier_block);
return 0;
err_misc:
rtnl_link_unregister(&tun_link_ops);
@@ -2427,6 +2548,7 @@ static void tun_cleanup(void)
{
misc_deregister(&tun_miscdev);
rtnl_link_unregister(&tun_link_ops);
+ unregister_netdevice_notifier(&tun_notifier_block);
}
/* Get an underlying socket object from tun file. Returns error unless file is
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 1d3e45f..e032ca3 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -481,10 +481,14 @@ out:
static int peek_head_len(struct sock *sk)
{
+ struct socket *sock = sk->sk_socket;
struct sk_buff *head;
int len = 0;
unsigned long flags;
+ if (sock->ops->peek_len)
+ return sock->ops->peek_len(sock);
+
spin_lock_irqsave(&sk->sk_receive_queue.lock, flags);
head = skb_peek(&sk->sk_receive_queue);
if (likely(head)) {
@@ -497,6 +501,16 @@ static int peek_head_len(struct sock *sk)
return len;
}
+static int sk_has_rx_data(struct sock *sk)
+{
+ struct socket *sock = sk->sk_socket;
+
+ if (sock->ops->peek_len)
+ return sock->ops->peek_len(sock);
+
+ return skb_queue_empty(&sk->sk_receive_queue);
+}
+
static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk)
{
struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
@@ -513,7 +527,7 @@ static int vhost_net_rx_peek_head_len(struct vhost_net *net,
struct sock *sk)
endtime = busy_clock() + vq->busyloop_timeout;
while (vhost_can_busy_poll(&net->dev, endtime) &&
- skb_queue_empty(&sk->sk_receive_queue) &&
+ !sk_has_rx_data(sk) &&
vhost_vq_avail_empty(&net->dev, vq))
cpu_relax_lowlatency();
diff --git a/include/linux/net.h b/include/linux/net.h
index 9aa49a0..b6b3843 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -185,6 +185,7 @@ struct proto_ops {
ssize_t (*splice_read)(struct socket *sock, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len, unsigned int flags);
int (*set_peek_off)(struct sock *sk, int val);
+ int (*peek_len)(struct socket *sock);
};
#define DECLARE_SOCKADDR(type, dst, src) \
--
2.7.4
John Fastabend
2016-Jun-30 04:56 UTC
[PATCH net-next V3 5/6] net: introduce NETDEV_CHANGE_TX_QUEUE_LEN
On 16-06-29 08:52 PM, Jason Wang wrote:> This patch introduces a new event - NETDEV_CHANGE_TX_QUEUE_LEN, this > will be triggered when tx_queue_len. It could be used by net device > who want to do some processing at that time. An example is tun who may > want to resize tx array when tx_queue_len is changed. > > Signed-off-by: Jason Wang <jasowang at redhat.com> > --- > include/linux/netdevice.h | 1 + > net/core/net-sysfs.c | 15 ++++++++++++++- > 2 files changed, 15 insertions(+), 1 deletion(-) > > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > index e84d9d2..7dc2ec7 100644 > --- a/include/linux/netdevice.h > +++ b/include/linux/netdevice.h > @@ -2237,6 +2237,7 @@ struct netdev_lag_lower_state_info { > #define NETDEV_PRECHANGEUPPER 0x001A > #define NETDEV_CHANGELOWERSTATE 0x001B > #define NETDEV_UDP_TUNNEL_PUSH_INFO 0x001C > +#define NETDEV_CHANGE_TX_QUEUE_LEN 0x001E > > int register_netdevice_notifier(struct notifier_block *nb); > int unregister_netdevice_notifier(struct notifier_block *nb); > diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c > index 7a0b616..6e4f347 100644 > --- a/net/core/net-sysfs.c > +++ b/net/core/net-sysfs.c > @@ -322,7 +322,20 @@ NETDEVICE_SHOW_RW(flags, fmt_hex); > > static int change_tx_queue_len(struct net_device *dev, unsigned long new_len) > { > - dev->tx_queue_len = new_len; > + int res, orig_len = dev->tx_queue_len; > + > + if (new_len != orig_len) { > + dev->tx_queue_len = new_len; > + res = call_netdevice_notifiers(NETDEV_CHANGE_TX_QUEUE_LEN, dev); > + res = notifier_to_errno(res); > + if (res) { > + netdev_err(dev, > + "refused to change device tx_queue_len\n"); > + dev->tx_queue_len = orig_len; > + return -EFAULT; > + } > + } > + > return 0; > } > >Acked-by: John Fastabend <john.r.fastabend at intel.com> Great timing I was just looking into this because I need it for the qdisc side. It looks like this covers the sysfs change but the tx_queue_len can also be changed via rtnetlink as well. So we need another patch for that path right? if (tb[IFLA_TXQLEN]) { unsigned long value = nla_get_u32(tb[IFLA_TXQLEN]); if (dev->tx_queue_len ^ value) status |= DO_SETLINK_NOTIFY; dev->tx_queue_len = value; } Thanks, John
Michael S. Tsirkin
2016-Jun-30 05:37 UTC
[PATCH net-next V3 0/6] switch to use tx skb array in tun
On Thu, Jun 30, 2016 at 11:52:53AM +0800, Jason Wang wrote:> Hi all: > > This series tries to switch to use skb array in tun. This is used to > eliminate the spinlock contention between producer and consumer. The > conversion was straightforward: just introdce a tx skb array and use > it instead of sk_receive_queue. > > A minor issue is to keep the tx_queue_len behaviour, since tun used to > use it for the length of sk_receive_queue. This is done through: > > - add the ability to resize multiple rings at once to avoid handling > partial resize failure for mutiple rings. > - add the support for zero length ring. > - introduce a notifier which was triggered when tx_queue_len was > changed for a netdev. > - resize all queues during the tx_queue_len changing. > > Tests shows about 15% improvement on guest rx pps: > > Before: ~1300000pps > After : ~1500000ppsSeries: Acked-by: Michael S. Tsirkin <mst at redhat.com>> Changes from V2: > - add multiple rings resizing support for ptr_ring/skb_array > - add zero length ring support > - introdce a NETDEV_CHANGE_TX_QUEUE_LEN > - drop new flags > > Changes from V1: > - switch to use skb array instead of a customized circular buffer > - add non-blocking support > - rename .peek to .peek_len > - drop lockless peeking since test show very minor improvement > > Jason Wang (5): > ptr_ring: support zero length ring > skb_array: minor tweak > skb_array: add wrappers for resizing > net: introduce NETDEV_CHANGE_TX_QUEUE_LEN > tun: switch to use skb array for tx > > Michael S. Tsirkin (1): > ptr_ring: support resizing multiple queues > > drivers/net/tun.c | 138 ++++++++++++++++++++++++++++++++++++--- > drivers/vhost/net.c | 16 ++++- > include/linux/net.h | 1 + > include/linux/netdevice.h | 1 + > include/linux/ptr_ring.h | 77 ++++++++++++++++++---- > include/linux/skb_array.h | 13 +++- > net/core/net-sysfs.c | 15 ++++- > tools/virtio/ringtest/ptr_ring.c | 5 ++ > 8 files changed, 243 insertions(+), 23 deletions(-) > > -- > 2.7.4
kbuild test robot
2016-Jun-30 06:20 UTC
[PATCH net-next V3 6/6] tun: switch to use skb array for tx
Hi, [auto build test WARNING on net-next/master] url: https://github.com/0day-ci/linux/commits/Jason-Wang/switch-to-use-tx-skb-array-in-tun/20160630-120656 coccinelle warnings: (new ones prefixed by >>)>> drivers/net/tun.c:1476:2-3: Unneeded semicolonPlease review and possibly fold the followup patch. --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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