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Date: Thu, 29 Nov 2007 12:17:32 -0800
From: "Shannon Nelson" <shannon.lee.nelson@...il.com>
To: netdev@...r.kernel.org
Subject: Re: [PATCH -mm] [RFC] I/OAT: Handle incoming udp through ioatdma
Argh - mind the line breaks...
sln
On Nov 29, 2007 12:08 PM, Nelson, Shannon <shannon.nelson@...el.com> wrote:
> [RFC] I/OAT: Handle incoming udp through ioatdma
>
> From: Shannon Nelson <shannon.nelson@...el.com>
>
> If the incoming udp packet is larger than sysctl_udp_dma_copybreak, try
> pushing it through the ioatdma asynchronous memcpy. This is very much
> the
> same as the tcp copy offload. This is an RFC because we know there are
> stability problems under high traffic.
>
> This code was originally proposed by the Capstone students at Portland
> State University: Aaron Armstrong, Greg Nishikawa, Sean Gayner, Toai
> Nguyen,
> Stephen Bekefi, and Derek Chiles.
>
> Signed-off-by: Shannon Nelson <shannon.nelson@...el.com>
> ---
>
> include/net/udp.h | 5 +++
> net/core/user_dma.c | 1 +
> net/ipv4/udp.c | 79
> ++++++++++++++++++++++++++++++++++++++++++++++++---
> 3 files changed, 81 insertions(+), 4 deletions(-)
>
> diff --git a/include/net/udp.h b/include/net/udp.h
> index 98755eb..d5e05d8 100644
> --- a/include/net/udp.h
> +++ b/include/net/udp.h
> @@ -173,4 +173,9 @@ extern void udp_proc_unregister(struct
> udp_seq_afinfo *afinfo);
> extern int udp4_proc_init(void);
> extern void udp4_proc_exit(void);
> #endif
> +
> +#ifdef CONFIG_NET_DMA
> +extern int sysctl_udp_dma_copybreak;
> +#endif
> +
> #endif /* _UDP_H */
> diff --git a/net/core/user_dma.c b/net/core/user_dma.c
> index 0ad1cd5..e876ca4 100644
> --- a/net/core/user_dma.c
> +++ b/net/core/user_dma.c
> @@ -34,6 +34,7 @@
> #define NET_DMA_DEFAULT_COPYBREAK 4096
>
> int sysctl_tcp_dma_copybreak = NET_DMA_DEFAULT_COPYBREAK;
> +int sysctl_udp_dma_copybreak = NET_DMA_DEFAULT_COPYBREAK;
>
> /**
> * dma_skb_copy_datagram_iovec - Copy a datagram to an iovec.
> diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
> index 69d4bd1..3b6d91c 100644
> --- a/net/ipv4/udp.c
> +++ b/net/ipv4/udp.c
> @@ -102,6 +102,8 @@
> #include <net/route.h>
> #include <net/checksum.h>
> #include <net/xfrm.h>
> +#include <net/netdma.h>
> +#include <linux/dmaengine.h>
> #include "udp_impl.h"
>
> /*
> @@ -819,6 +821,11 @@ int udp_recvmsg(struct kiocb *iocb, struct sock
> *sk, struct msghdr *msg,
> unsigned int ulen, copied;
> int err;
> int is_udplite = IS_UDPLITE(sk);
> +#ifdef CONFIG_NET_DMA
> + struct dma_chan *dma_chan = NULL;
> + struct dma_pinned_list *pinned_list = NULL;
> + dma_cookie_t dma_cookie = 0;
> +#endif
>
> /*
> * Check any passed addresses
> @@ -829,6 +836,18 @@ int udp_recvmsg(struct kiocb *iocb, struct sock
> *sk, struct msghdr *msg,
> if (flags & MSG_ERRQUEUE)
> return ip_recv_error(sk, msg, len);
>
> +#ifdef CONFIG_NET_DMA
> + preempt_disable();
> + if ((len > sysctl_udp_dma_copybreak) &&
> + !(flags & MSG_PEEK) &&
> + __get_cpu_var(softnet_data).net_dma) {
> +
> + preempt_enable_no_resched();
> + pinned_list = dma_pin_iovec_pages(msg->msg_iov, len);
> + } else
> + preempt_enable_no_resched();
> +#endif
> +
> try_again:
> skb = skb_recv_datagram(sk, flags, noblock, &err);
> if (!skb)
> @@ -852,10 +871,30 @@ try_again:
> goto csum_copy_err;
> }
>
> - if (skb_csum_unnecessary(skb))
> - err = skb_copy_datagram_iovec(skb, sizeof(struct
> udphdr),
> - msg->msg_iov, copied
> );
> - else {
> + if (skb_csum_unnecessary(skb)) {
> +#ifdef CONFIG_NET_DMA
> + if (pinned_list && !dma_chan)
> + dma_chan = get_softnet_dma();
> + if (dma_chan) {
> + dma_cookie = dma_skb_copy_datagram_iovec(
> + dma_chan, skb, sizeof(struct
> udphdr),
> + msg->msg_iov, copied,
> pinned_list);
> + if (dma_cookie < 0) {
> + printk(KERN_ALERT "dma_cookie < 0\n");
> +
> + /* Exception. Bailout! */
> + if (!copied)
> + copied = -EFAULT;
> + goto out_free;
> + }
> + err = 0;
> + }
> + else
> +#endif
> + err = skb_copy_datagram_iovec(skb,
> + sizeof(struct
> udphdr),
> + msg->msg_iov,
> copied);
> + } else {
> err = skb_copy_and_csum_datagram_iovec(skb,
> sizeof(struct udphdr), msg->msg_iov);
>
> if (err == -EINVAL)
> @@ -882,6 +921,35 @@ try_again:
> if (flags & MSG_TRUNC)
> err = ulen;
>
> +#ifdef CONFIG_NET_DMA
> + if (dma_chan) {
> + struct sk_buff *skb;
> + dma_cookie_t done, used;
> +
> + dma_async_memcpy_issue_pending(dma_chan);
> +
> + while (dma_async_memcpy_complete(dma_chan, dma_cookie,
> &done,
> + &used) == DMA_IN_PROGRESS) {
> + /* do partial cleanup of sk_async_wait_queue */
> + while ((skb =
> skb_peek(&sk->sk_async_wait_queue)) &&
> +
> (dma_async_is_complete(skb->dma_cookie,
> + done, used) == DMA_SUCCESS)) {
> + __skb_dequeue(&sk->sk_async_wait_queue);
> + kfree_skb(skb);
> + }
> + }
> +
> + /* Safe to free early-copied skbs now */
> + __skb_queue_purge(&sk->sk_async_wait_queue);
> + dma_chan_put(dma_chan);
> + dma_chan = NULL;
> + }
> + if (pinned_list) {
> + dma_unpin_iovec_pages(pinned_list);
> + pinned_list = NULL;
> + }
> +#endif
> +
> out_free:
> skb_free_datagram(sk, skb);
> out:
> @@ -906,6 +974,9 @@ int udp_disconnect(struct sock *sk, int flags)
> */
>
> sk->sk_state = TCP_CLOSE;
> +#ifdef CONFIG_NET_DMA
> + __skb_queue_purge(&sk->sk_async_wait_queue);
> +#endif
> inet->daddr = 0;
> inet->dport = 0;
> sk->sk_bound_dev_if = 0;
>
>
> --
> ======================================================================
> Mr. Shannon Nelson LAN Access Division, Intel Corp.
> Shannon.Nelson@...el.com I don't speak for Intel
> (503) 712-7659 Parents can't afford to be squeamish.
> -
> To unsubscribe from this list: send the line "unsubscribe netdev" in
> the body of a message to majordomo@...r.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
--
==============================================
Mr. Shannon Nelson Parents can't afford to be squeamish.
-
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