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Message-ID: <Pine.LNX.4.64.0705271032460.2532@kivilampi-30.cs.helsinki.fi>
Date: Sun, 27 May 2007 10:38:07 +0300 (EEST)
From: "Ilpo Järvinen" <ilpo.jarvinen@...sinki.fi>
To: David Miller <davem@...emloft.net>
cc: Netdev <netdev@...r.kernel.org>
Subject: Re: [PATCH 6/9] [TCP]: Reorganize lost marking code
On Sat, 26 May 2007, Ilpo Järvinen wrote:
> -static void tcp_update_scoreboard_fack(struct sock *sk, u32 entry_seq,
> - int fast_rexmit)
> +struct sk_buff *tcp_update_scoreboard_fack(struct sock *sk, u32 entry_seq,
> + int fast_rexmit)
Noticed that the static got dropped here unintentionally, 2nd try included
below.
[PATCH 6/9] [TCP]: Reorganize lost marking code
The indentation started to get scary, so I reorganized code so
that some trivial ifs are in tcp_update_scoreboard and the main
loops remain in tcp_update_scoreboard_fack.
It's much easier to view the actual changes with git-diff -w
than from the messy looking (default) diff.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@...sinki.fi>
---
net/ipv4/tcp_input.c | 157 +++++++++++++++++++++++++-------------------------
1 files changed, 79 insertions(+), 78 deletions(-)
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 452a3b0..c5eda37 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1866,7 +1866,6 @@ static void tcp_mark_head_lost_single(struct sock *sk)
before(tp->snd_una, tp->high_seq)) {
TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;
tp->lost_out += tcp_skb_pcount(skb);
- tcp_sync_left_out(tp);
}
}
@@ -1905,99 +1904,85 @@ static void tcp_mark_head_lost_single(struct sock *sk)
* Key difference here is that FACK uses both SACK blocks and holes while
* RFC3517 is using only SACK blocks when counting for reordering.
*/
-static void tcp_update_scoreboard_fack(struct sock *sk, u32 entry_seq,
- int fast_rexmit)
+static struct sk_buff *tcp_update_scoreboard_fack(struct sock *sk,
+ u32 entry_seq,
+ int fast_rexmit)
{
struct tcp_sock *tp = tcp_sk(sk);
/* Beware: timedout_continue might be pointing to sk_write_queue */
struct sk_buff *timedout_continue = NULL;
struct sk_buff *skb;
-
- if (!tp->sacked_out) {
- if (IsFack(tp) || fast_rexmit) {
- tcp_mark_head_lost_single(sk);
- skb = tcp_write_queue_head(sk);
- timedout_continue = tcp_write_queue_next(sk, skb);
- }
-
+ unsigned int holes_seen = 0;
+
+ skb = tcp_write_queue_find(sk, entry_seq);
+ /* If this ever becomes expensive, it can be delayed */
+ timedout_continue = tcp_write_queue_next(sk, skb);
+ if (entry_seq != tp->highest_sack) {
+ /* Not interested in "the last" SACKed one we got */
+ /* RFC: find_below could help here too */
+ skb = tcp_write_queue_prev(sk, skb);
+ if (IsFack(tp) && tcp_skb_timedout(sk, skb) &&
+ (tp->fackets_out < tp->packets_out)) {
+ timedout_continue = tcp_write_queue_find(sk, tp->highest_sack);
+ timedout_continue = tcp_write_queue_next(sk, timedout_continue);
+ } else
+ timedout_continue = NULL;
} else {
- unsigned int holes_seen = 0;
-
- skb = tcp_write_queue_find(sk, entry_seq);
- /* If this ever becomes expensive, it can be delayed */
- timedout_continue = tcp_write_queue_next(sk, skb);
- if (entry_seq != tp->highest_sack) {
- /* Not interested in "the last" SACKed one we got */
- /* RFC: find_below could help here too */
- skb = tcp_write_queue_prev(sk, skb);
- if (IsFack(tp) && tcp_skb_timedout(sk, skb) &&
- (tp->fackets_out < tp->packets_out)) {
- timedout_continue = tcp_write_queue_find(sk, tp->highest_sack);
- timedout_continue = tcp_write_queue_next(sk, timedout_continue);
- } else
- timedout_continue = NULL;
- } else {
- unsigned int reord_count = IsFack(tp) ? 0 : 1;
-
- /* Phase I: Search until TCP can mark */
- tcp_for_write_queue_backwards_from(skb, sk) {
- if ((tp->fackets_out <= tp->sacked_out +
- tp->lost_out +
- holes_seen) ||
- (TCP_SKB_CB(skb)->sacked & TCPCB_LOST))
- goto backwards_walk_done;
-
- if (IsFack(tp) && tcp_skb_timedout(sk, skb))
- break;
- else
- timedout_continue = NULL;
-
- if (IsFack(tp) ||
- (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED))
- reord_count += tcp_skb_pcount(skb);
- if (reord_count > tp->reordering) {
- if (after(TCP_SKB_CB(skb)->seq, tp->high_seq)) {
- /* RFC: should we have find_below? */
- skb = tcp_write_queue_find(sk, tp->high_seq);
- /* Timedout top is again uncertain? */
- if (tcp_skb_timedout(sk, skb))
- timedout_continue = skb;
- skb = tcp_write_queue_prev(sk, skb);
- }
- /* TODO?: do skb fragmentation if necessary */
- break;
- }
-
- if (!(TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED))
- holes_seen += tcp_skb_pcount(skb);
- }
- }
+ unsigned int reord_count = IsFack(tp) ? 0 : 1;
- /* Phase II: Marker */
+ /* Phase I: Search until TCP can mark */
tcp_for_write_queue_backwards_from(skb, sk) {
if ((tp->fackets_out <= tp->sacked_out + tp->lost_out +
holes_seen) ||
(TCP_SKB_CB(skb)->sacked & TCPCB_LOST))
goto backwards_walk_done;
- if (!(TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)) {
- TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;
- tp->lost_out += tcp_skb_pcount(skb);
- tcp_verify_retransmit_hint(tp, skb);
+ if (IsFack(tp) && tcp_skb_timedout(sk, skb))
+ break;
+ else
+ timedout_continue = NULL;
+
+ if (IsFack(tp) ||
+ (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED))
+ reord_count += tcp_skb_pcount(skb);
+ if (reord_count > tp->reordering) {
+ if (after(TCP_SKB_CB(skb)->seq, tp->high_seq)) {
+ /* RFC: should we have find_below? */
+ skb = tcp_write_queue_find(sk, tp->high_seq);
+ /* Timedout top is again uncertain? */
+ if (tcp_skb_timedout(sk, skb))
+ timedout_continue = skb;
+ skb = tcp_write_queue_prev(sk, skb);
+ }
+ /* TODO?: do skb fragmentation if necessary */
+ break;
}
+
+ if (!(TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED))
+ holes_seen += tcp_skb_pcount(skb);
}
+ }
+
+ /* Phase II: Marker */
+ tcp_for_write_queue_backwards_from(skb, sk) {
+ if ((tp->fackets_out <= tp->sacked_out + tp->lost_out +
+ holes_seen) ||
+ (TCP_SKB_CB(skb)->sacked & TCPCB_LOST))
+ goto backwards_walk_done;
- /* Phase III: Nothing is still marked?, mark head then */
- if ((IsFack(tp) || fast_rexmit) && !tp->lost_out)
- tcp_mark_head_lost_single(sk);
+ if (!(TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)) {
+ TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;
+ tp->lost_out += tcp_skb_pcount(skb);
+ tcp_verify_retransmit_hint(tp, skb);
+ }
}
-backwards_walk_done:
- /* Continue with timedout work */
- if (IsFack(tp) && (timedout_continue != NULL))
- tcp_timedout_mark_forward(sk, timedout_continue);
+ /* Phase III: Nothing is still marked?, mark head then */
+ if ((IsFack(tp) || fast_rexmit) && !tp->lost_out)
+ tcp_mark_head_lost_single(sk);
- tcp_sync_left_out(tp);
+backwards_walk_done:
+ return timedout_continue;
}
/* Account newly detected lost packet(s) */
@@ -2005,11 +1990,27 @@ static void tcp_update_scoreboard(struct sock *sk, u32 sack_entry_seq,
int fast_rexmit)
{
struct tcp_sock *tp = tcp_sk(sk);
+ struct sk_buff *skb = NULL;
+
+ if (!IsReno(tp)) {
+ if (!tp->sacked_out) {
+ if (IsFack(tp) || fast_rexmit) {
+ tcp_mark_head_lost_single(sk);
+ skb = tcp_write_queue_head(sk);
+ skb = tcp_write_queue_next(sk, skb);
+ }
+ } else
+ skb = tcp_update_scoreboard_fack(sk, sack_entry_seq,
+ fast_rexmit);
- if (!IsReno(tp))
- tcp_update_scoreboard_fack(sk, sack_entry_seq, fast_rexmit);
- else
+ /* Continue with timedout work */
+ if (IsFack(tp) && (skb != NULL))
+ tcp_timedout_mark_forward(sk, skb);
+
+ } else
tcp_mark_head_lost_single(sk);
+
+ tcp_sync_left_out(tp);
}
/* CWND moderation, preventing bursts due to too big ACKs
--
1.5.0.6
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