From: Herbert Xu <[EMAIL PROTECTED]>
Date: Mon, 22 Aug 2005 14:21:40 +1000
> > A further simplification seems possible, in that all of the
> > tp->*_out modifications can be keyed upon the "skb_ever_sent"
> > arg to tcp_fragment().
>
> Yes this is a good idea.
>
> > + if (skb_ever_sent) {
>
> We could check TCP_SKB_CB(skb)->end_seq versus tp->snd_nxt
> instead of tracking it manually.
Ok, this is a full redo of the "do not disable TSO on loss" patch
including all of the refinements and fixes we've discussed so
far.
Please give it a stare, thanks.
diff-tree 3f883f06db07d55ef4ef02f7d9e6aff5a0217916 (from
b94c07bcb646075b82302616c369b1f3006682d0)
Author: David S. Miller <[EMAIL PROTECTED]>
Date: Sun Aug 21 23:23:19 2005 -0700
[TCP]: Keep TSO enabled even during loss events.
All we need to do is resegment the queue so that
we record SACK information accurately. The edges
of the SACK blocks guide our resegmenting decisions.
With help from Herbert Xu.
Signed-off-by: David S. Miller <[EMAIL PROTECTED]>
diff --git a/include/net/tcp.h b/include/net/tcp.h
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -855,6 +855,7 @@ extern int tcp_retransmit_skb(struct soc
extern void tcp_xmit_retransmit_queue(struct sock *);
extern void tcp_simple_retransmit(struct sock *);
extern int tcp_trim_head(struct sock *, struct sk_buff *, u32);
+extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int);
extern void tcp_send_probe0(struct sock *);
extern void tcp_send_partial(struct sock *);
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -909,14 +909,6 @@ tcp_sacktag_write_queue(struct sock *sk,
int flag = 0;
int i;
- /* So, SACKs for already sent large segments will be lost.
- * Not good, but alternative is to resegment the queue. */
- if (sk->sk_route_caps & NETIF_F_TSO) {
- sk->sk_route_caps &= ~NETIF_F_TSO;
- sock_set_flag(sk, SOCK_NO_LARGESEND);
- tp->mss_cache = tp->mss_cache;
- }
-
if (!tp->sacked_out)
tp->fackets_out = 0;
prior_fackets = tp->fackets_out;
@@ -964,20 +956,40 @@ tcp_sacktag_write_queue(struct sock *sk,
flag |= FLAG_DATA_LOST;
sk_stream_for_retrans_queue(skb, sk) {
- u8 sacked = TCP_SKB_CB(skb)->sacked;
- int in_sack;
+ int in_sack, pcount;
+ u8 sacked;
/* The retransmission queue is always in order, so
* we can short-circuit the walk early.
*/
- if(!before(TCP_SKB_CB(skb)->seq, end_seq))
+ if (!before(TCP_SKB_CB(skb)->seq, end_seq))
break;
- fack_count += tcp_skb_pcount(skb);
+ pcount = tcp_skb_pcount(skb);
+
+ if (pcount > 1 &&
+ (after(start_seq, TCP_SKB_CB(skb)->seq) ||
+ before(end_seq, TCP_SKB_CB(skb)->end_seq))) {
+ unsigned int pkt_len;
+
+ if (after(start_seq, TCP_SKB_CB(skb)->seq))
+ pkt_len = (start_seq -
+ TCP_SKB_CB(skb)->seq);
+ else
+ pkt_len = (end_seq -
+ TCP_SKB_CB(skb)->seq);
+ if (tcp_fragment(sk, skb, pkt_len, pkt_len))
+ break;
+ pcount = tcp_skb_pcount(skb);
+ }
+
+ fack_count += pcount;
in_sack = !after(start_seq, TCP_SKB_CB(skb)->seq) &&
!before(end_seq, TCP_SKB_CB(skb)->end_seq);
+ sacked = TCP_SKB_CB(skb)->sacked;
+
/* Account D-SACK for retransmitted packet. */
if ((dup_sack && in_sack) &&
(sacked & TCPCB_RETRANS) &&
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -427,11 +427,11 @@ static void tcp_set_skb_tso_segs(struct
* packet to the list. This won't be called frequently, I hope.
* Remember, these are still headerless SKBs at this point.
*/
-static int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len,
unsigned int mss_now)
+int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len, unsigned int
mss_now)
{
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *buff;
- int nsize;
+ int nsize, old_factor;
u16 flags;
nsize = skb_headlen(skb) - len;
@@ -489,18 +489,33 @@ static int tcp_fragment(struct sock *sk,
tp->left_out -= tcp_skb_pcount(skb);
}
+ old_factor = tcp_skb_pcount(skb);
+
/* Fix up tso_factor for both original and new SKB. */
tcp_set_skb_tso_segs(sk, skb, mss_now);
tcp_set_skb_tso_segs(sk, buff, mss_now);
- if (TCP_SKB_CB(skb)->sacked & TCPCB_LOST) {
- tp->lost_out += tcp_skb_pcount(skb);
- tp->left_out += tcp_skb_pcount(skb);
- }
+ /* If this packet has been sent out already, we must
+ * adjust the various packet counters.
+ */
+ if (after(tp->snd_nxt, TCP_SKB_CB(buff)->end_seq)) {
+ int diff = old_factor - tcp_skb_pcount(skb) -
+ tcp_skb_pcount(buff);
- if (TCP_SKB_CB(buff)->sacked&TCPCB_LOST) {
- tp->lost_out += tcp_skb_pcount(buff);
- tp->left_out += tcp_skb_pcount(buff);
+ tp->packets_out -= diff;
+ if (diff > 0) {
+ tp->fackets_out -= diff;
+ if ((int)tp->fackets_out < 0)
+ tp->fackets_out = 0;
+ if (TCP_SKB_CB(skb)->sacked & TCPCB_LOST) {
+ tp->lost_out -= diff;
+ if ((int)tp->lost_out < 0)
+ tp->lost_out = 0;
+ tp->left_out -= diff;
+ if ((int)tp->left_out < 0)
+ tp->left_out = 0;
+ }
+ }
}
/* Link BUFF into the send queue. */
@@ -1346,12 +1361,6 @@ int tcp_retransmit_skb(struct sock *sk,
if (before(TCP_SKB_CB(skb)->seq, tp->snd_una)) {
if (before(TCP_SKB_CB(skb)->end_seq, tp->snd_una))
BUG();
-
- if (sk->sk_route_caps & NETIF_F_TSO) {
- sk->sk_route_caps &= ~NETIF_F_TSO;
- sock_set_flag(sk, SOCK_NO_LARGESEND);
- }
-
if (tcp_trim_head(sk, skb, tp->snd_una - TCP_SKB_CB(skb)->seq))
return -ENOMEM;
}
@@ -1366,22 +1375,8 @@ int tcp_retransmit_skb(struct sock *sk,
return -EAGAIN;
if (skb->len > cur_mss) {
- int old_factor = tcp_skb_pcount(skb);
- int diff;
-
if (tcp_fragment(sk, skb, cur_mss, cur_mss))
return -ENOMEM; /* We'll try again later. */
-
- /* New SKB created, account for it. */
- diff = old_factor - tcp_skb_pcount(skb) -
- tcp_skb_pcount(skb->next);
- tp->packets_out -= diff;
-
- if (diff > 0) {
- tp->fackets_out -= diff;
- if ((int)tp->fackets_out < 0)
- tp->fackets_out = 0;
- }
}
/* Collapse two adjacent packets if worthwhile and we can. */
@@ -1980,12 +1975,6 @@ int tcp_write_wakeup(struct sock *sk)
TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
if (tcp_fragment(sk, skb, seg_size, mss))
return -1;
- /* SWS override triggered forced fragmentation.
- * Disable TSO, the connection is too sick. */
- if (sk->sk_route_caps & NETIF_F_TSO) {
- sock_set_flag(sk, SOCK_NO_LARGESEND);
- sk->sk_route_caps &= ~NETIF_F_TSO;
- }
} else if (!tcp_skb_pcount(skb))
tcp_set_skb_tso_segs(sk, skb, mss);
-
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
