| Message ID | alpine.DEB.1.00.1010211303390.30535@pokey.mtv.corp.google.com |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Tom Herbert <therbert@google.com> Date: Thu, 21 Oct 2010 13:17:08 -0700 (PDT) > @@ -822,8 +822,10 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it, > &md5); > tcp_header_size = tcp_options_size + sizeof(struct tcphdr); > > - if (tcp_packets_in_flight(tp) == 0) > + if (tcp_packets_in_flight(tp) == 0) { > tcp_ca_event(sk, CA_EVENT_TX_START); > + skb->ooo_okay = 1; > + } > You'll need to clear this flag the moment the first transmit of this packet happens, otherwise OOO won't be handled correctly in the event that fast retransmit is necessary later. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sun, Oct 24, 2010 at 3:32 PM, David Miller <davem@davemloft.net> wrote: > From: Tom Herbert <therbert@google.com> > Date: Thu, 21 Oct 2010 13:17:08 -0700 (PDT) > >> @@ -822,8 +822,10 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it, >> &md5); >> tcp_header_size = tcp_options_size + sizeof(struct tcphdr); >> >> - if (tcp_packets_in_flight(tp) == 0) >> + if (tcp_packets_in_flight(tp) == 0) { >> tcp_ca_event(sk, CA_EVENT_TX_START); >> + skb->ooo_okay = 1; >> + } >> > > You'll need to clear this flag the moment the first transmit of > this packet happens, otherwise OOO won't be handled correctly in > the event that fast retransmit is necessary later. > Would this be sufficient: @@ -825,7 +825,8 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb if (tcp_packets_in_flight(tp) == 0) { tcp_ca_event(sk, CA_EVENT_TX_START); skb->ooo_okay = 1; - } + } else + skb->ooo_okay = 0; -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Tom Herbert <therbert@google.com> Date: Mon, 25 Oct 2010 10:02:05 -0700 > Would this be sufficient: > > @@ -825,7 +825,8 @@ static int tcp_transmit_skb(struct sock *sk, > struct sk_buff *skb > if (tcp_packets_in_flight(tp) == 0) { > tcp_ca_event(sk, CA_EVENT_TX_START); > skb->ooo_okay = 1; > - } > + } else > + skb->ooo_okay = 0; Or, alternatively, you could clear it at the point it's tested in the device transmit path. This might make the changes for SCTP and other protocols much easier. For now, either way is fine with me. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi, Am Donnerstag 21 Oktober 2010 schrieb Tom Herbert: > In dev_pick_tx, don't do work in calculating queue index or setting > the index in the sock unless the device has more than one queue. This > allows the sock to be set only with a queue index of a multi-queue > device which is desirable if device are stacked like in a tunnel. > > We also allow the mapping of a socket to queue to be changed. To > maintain in order packet transmission a flag (ooo_okay) has been > added to the sk_buff structure. If a transport layer sets this flag > on a packet, the transmit queue can be changed for the socket. > Presumably, the transport would set this if there was no possbility > of creating OOO packets (for instance, there are no packets in flight > for the socket). This patch includes the modification in TCP output > for setting this flag. > > Signed-off-by: Tom Herbert <therbert@google.com> > --- [...] > diff --git a/net/core/dev.c b/net/core/dev.c > index b2269ac..a538ed5 100644 > --- a/net/core/dev.c > +++ b/net/core/dev.c > @@ -2123,28 +2123,32 @@ static struct netdev_queue *dev_pick_tx(struct net_device *dev, > struct sk_buff *skb) > { > int queue_index; > - const struct net_device_ops *ops = dev->netdev_ops; > > - if (ops->ndo_select_queue) { > - queue_index = ops->ndo_select_queue(dev, skb); > - queue_index = dev_cap_txqueue(dev, queue_index); > - } else { > + if (dev->real_num_tx_queues > 1) { > struct sock *sk = skb->sk; > + > queue_index = sk_tx_queue_get(sk); > - if (queue_index < 0) { > > - queue_index = 0; > - if (dev->real_num_tx_queues > 1) > + if (queue_index < 0 || skb->ooo_okay || > + queue_index >= dev->real_num_tx_queues) { > + const struct net_device_ops *ops = dev->netdev_ops; > + int old_index = queue_index; > + > + if (ops->ndo_select_queue) { > + queue_index = ops->ndo_select_queue(dev, skb); > + queue_index = dev_cap_txqueue(dev, queue_index); > + } else > queue_index = skb_tx_hash(dev, skb); Wouldn't that break mac80211 QoS again for bridged AP mode interfaces (see commit deabc772f39405054a438d711f408d2d94d26d96, "net: fix tx queue selection for bridged devices implementing select_queue")? Helmut -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
> Wouldn't that break mac80211 QoS again for bridged AP mode interfaces (see > commit deabc772f39405054a438d711f408d2d94d26d96, "net: fix tx queue selection > for bridged devices implementing select_queue")? > Yes, looks like that would break. I'll fix that. If a device only has one real TX queue should we still call ndo_select_queue, or can we bypass it? (to save one conditional) Thanks, Tom -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Tom Herbert <therbert@google.com> Date: Tue, 26 Oct 2010 08:32:59 -0700 >> Wouldn't that break mac80211 QoS again for bridged AP mode interfaces (see >> commit deabc772f39405054a438d711f408d2d94d26d96, "net: fix tx queue selection >> for bridged devices implementing select_queue")? >> > Yes, looks like that would break. I'll fix that. > > If a device only has one real TX queue should we still call > ndo_select_queue, or can we bypass it? (to save one conditional) Probably bypass, for now. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index e6ba898..19f37a6 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -386,9 +386,10 @@ struct sk_buff { #else __u8 deliver_no_wcard:1; #endif + __u8 ooo_okay:1; kmemcheck_bitfield_end(flags2); - /* 0/14 bit hole */ + /* 0/13 bit hole */ #ifdef CONFIG_NET_DMA dma_cookie_t dma_cookie; diff --git a/net/core/dev.c b/net/core/dev.c index b2269ac..a538ed5 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2123,28 +2123,32 @@ static struct netdev_queue *dev_pick_tx(struct net_device *dev, struct sk_buff *skb) { int queue_index; - const struct net_device_ops *ops = dev->netdev_ops; - if (ops->ndo_select_queue) { - queue_index = ops->ndo_select_queue(dev, skb); - queue_index = dev_cap_txqueue(dev, queue_index); - } else { + if (dev->real_num_tx_queues > 1) { struct sock *sk = skb->sk; + queue_index = sk_tx_queue_get(sk); - if (queue_index < 0) { - queue_index = 0; - if (dev->real_num_tx_queues > 1) + if (queue_index < 0 || skb->ooo_okay || + queue_index >= dev->real_num_tx_queues) { + const struct net_device_ops *ops = dev->netdev_ops; + int old_index = queue_index; + + if (ops->ndo_select_queue) { + queue_index = ops->ndo_select_queue(dev, skb); + queue_index = dev_cap_txqueue(dev, queue_index); + } else queue_index = skb_tx_hash(dev, skb); - if (sk) { + if (queue_index != old_index && sk) { struct dst_entry *dst = rcu_dereference_check(sk->sk_dst_cache, 1); if (dst && skb_dst(skb) == dst) sk_tx_queue_set(sk, queue_index); } } - } + } else + queue_index = 0; skb_set_queue_mapping(skb, queue_index); return netdev_get_tx_queue(dev, queue_index); diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 05b1ecf..67b9c9e 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -822,8 +822,10 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it, &md5); tcp_header_size = tcp_options_size + sizeof(struct tcphdr); - if (tcp_packets_in_flight(tp) == 0) + if (tcp_packets_in_flight(tp) == 0) { tcp_ca_event(sk, CA_EVENT_TX_START); + skb->ooo_okay = 1; + } skb_push(skb, tcp_header_size); skb_reset_transport_header(skb);
In dev_pick_tx, don't do work in calculating queue index or setting the index in the sock unless the device has more than one queue. This allows the sock to be set only with a queue index of a multi-queue device which is desirable if device are stacked like in a tunnel. We also allow the mapping of a socket to queue to be changed. To maintain in order packet transmission a flag (ooo_okay) has been added to the sk_buff structure. If a transport layer sets this flag on a packet, the transmit queue can be changed for the socket. Presumably, the transport would set this if there was no possbility of creating OOO packets (for instance, there are no packets in flight for the socket). This patch includes the modification in TCP output for setting this flag. Signed-off-by: Tom Herbert <therbert@google.com> --- include/linux/skbuff.h | 3 ++- net/core/dev.c | 24 ++++++++++++++---------- net/ipv4/tcp_output.c | 4 +++- 3 files changed, 19 insertions(+), 12 deletions(-)