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Date: Thu, 29 Nov 2007 12:08:26 -0800
From: "Nelson, Shannon" <shannon.nelson@...el.com>
To: <netdev@...r.kernel.org>
Subject: [PATCH -mm] [RFC] I/OAT: Handle incoming udp through ioatdma
[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.
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