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authorDavid S. Miller <davem@davemloft.net>2012-07-09 16:07:30 -0700
committerDavid S. Miller <davem@davemloft.net>2012-07-10 20:31:36 -0700
commit4aabd8ef8c43677cfee3e1e36c5a79edddb41942 (patch)
treea826352ad00ffcc1632edecfe4ebd77db1301e4b /net/ipv4/tcp_input.c
parentad7eee98bef92481581060801bdfd1b25a6106c0 (diff)
tcp: Move dynamnic metrics handling into seperate file.
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_input.c')
-rw-r--r--net/ipv4/tcp_input.c188
1 files changed, 2 insertions, 186 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index ca0d0e7c9778..055ac49b8b40 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -93,7 +93,6 @@ int sysctl_tcp_rfc1337 __read_mostly;
int sysctl_tcp_max_orphans __read_mostly = NR_FILE;
int sysctl_tcp_frto __read_mostly = 2;
int sysctl_tcp_frto_response __read_mostly;
-int sysctl_tcp_nometrics_save __read_mostly;
int sysctl_tcp_thin_dupack __read_mostly;
@@ -701,7 +700,7 @@ static void tcp_rtt_estimator(struct sock *sk, const __u32 mrtt)
/* Calculate rto without backoff. This is the second half of Van Jacobson's
* routine referred to above.
*/
-static inline void tcp_set_rto(struct sock *sk)
+void tcp_set_rto(struct sock *sk)
{
const struct tcp_sock *tp = tcp_sk(sk);
/* Old crap is replaced with new one. 8)
@@ -728,109 +727,6 @@ static inline void tcp_set_rto(struct sock *sk)
tcp_bound_rto(sk);
}
-/* Save metrics learned by this TCP session.
- This function is called only, when TCP finishes successfully
- i.e. when it enters TIME-WAIT or goes from LAST-ACK to CLOSE.
- */
-void tcp_update_metrics(struct sock *sk)
-{
- struct tcp_sock *tp = tcp_sk(sk);
- struct dst_entry *dst = __sk_dst_get(sk);
-
- if (sysctl_tcp_nometrics_save)
- return;
-
- if (dst && (dst->flags & DST_HOST)) {
- const struct inet_connection_sock *icsk = inet_csk(sk);
- int m;
- unsigned long rtt;
-
- dst_confirm(dst);
-
- if (icsk->icsk_backoff || !tp->srtt) {
- /* This session failed to estimate rtt. Why?
- * Probably, no packets returned in time.
- * Reset our results.
- */
- if (!(dst_metric_locked(dst, RTAX_RTT)))
- dst_metric_set(dst, RTAX_RTT, 0);
- return;
- }
-
- rtt = dst_metric_rtt(dst, RTAX_RTT);
- m = rtt - tp->srtt;
-
- /* If newly calculated rtt larger than stored one,
- * store new one. Otherwise, use EWMA. Remember,
- * rtt overestimation is always better than underestimation.
- */
- if (!(dst_metric_locked(dst, RTAX_RTT))) {
- if (m <= 0)
- set_dst_metric_rtt(dst, RTAX_RTT, tp->srtt);
- else
- set_dst_metric_rtt(dst, RTAX_RTT, rtt - (m >> 3));
- }
-
- if (!(dst_metric_locked(dst, RTAX_RTTVAR))) {
- unsigned long var;
- if (m < 0)
- m = -m;
-
- /* Scale deviation to rttvar fixed point */
- m >>= 1;
- if (m < tp->mdev)
- m = tp->mdev;
-
- var = dst_metric_rtt(dst, RTAX_RTTVAR);
- if (m >= var)
- var = m;
- else
- var -= (var - m) >> 2;
-
- set_dst_metric_rtt(dst, RTAX_RTTVAR, var);
- }
-
- if (tcp_in_initial_slowstart(tp)) {
- /* Slow start still did not finish. */
- if (dst_metric(dst, RTAX_SSTHRESH) &&
- !dst_metric_locked(dst, RTAX_SSTHRESH) &&
- (tp->snd_cwnd >> 1) > dst_metric(dst, RTAX_SSTHRESH))
- dst_metric_set(dst, RTAX_SSTHRESH, tp->snd_cwnd >> 1);
- if (!dst_metric_locked(dst, RTAX_CWND) &&
- tp->snd_cwnd > dst_metric(dst, RTAX_CWND))
- dst_metric_set(dst, RTAX_CWND, tp->snd_cwnd);
- } else if (tp->snd_cwnd > tp->snd_ssthresh &&
- icsk->icsk_ca_state == TCP_CA_Open) {
- /* Cong. avoidance phase, cwnd is reliable. */
- if (!dst_metric_locked(dst, RTAX_SSTHRESH))
- dst_metric_set(dst, RTAX_SSTHRESH,
- max(tp->snd_cwnd >> 1, tp->snd_ssthresh));
- if (!dst_metric_locked(dst, RTAX_CWND))
- dst_metric_set(dst, RTAX_CWND,
- (dst_metric(dst, RTAX_CWND) +
- tp->snd_cwnd) >> 1);
- } else {
- /* Else slow start did not finish, cwnd is non-sense,
- ssthresh may be also invalid.
- */
- if (!dst_metric_locked(dst, RTAX_CWND))
- dst_metric_set(dst, RTAX_CWND,
- (dst_metric(dst, RTAX_CWND) +
- tp->snd_ssthresh) >> 1);
- if (dst_metric(dst, RTAX_SSTHRESH) &&
- !dst_metric_locked(dst, RTAX_SSTHRESH) &&
- tp->snd_ssthresh > dst_metric(dst, RTAX_SSTHRESH))
- dst_metric_set(dst, RTAX_SSTHRESH, tp->snd_ssthresh);
- }
-
- if (!dst_metric_locked(dst, RTAX_REORDERING)) {
- if (dst_metric(dst, RTAX_REORDERING) < tp->reordering &&
- tp->reordering != sysctl_tcp_reordering)
- dst_metric_set(dst, RTAX_REORDERING, tp->reordering);
- }
- }
-}
-
__u32 tcp_init_cwnd(const struct tcp_sock *tp, const struct dst_entry *dst)
{
__u32 cwnd = (dst ? dst_metric(dst, RTAX_INITCWND) : 0);
@@ -867,7 +763,7 @@ void tcp_enter_cwr(struct sock *sk, const int set_ssthresh)
* Packet counting of FACK is based on in-order assumptions, therefore TCP
* disables it when reordering is detected
*/
-static void tcp_disable_fack(struct tcp_sock *tp)
+void tcp_disable_fack(struct tcp_sock *tp)
{
/* RFC3517 uses different metric in lost marker => reset on change */
if (tcp_is_fack(tp))
@@ -881,86 +777,6 @@ static void tcp_dsack_seen(struct tcp_sock *tp)
tp->rx_opt.sack_ok |= TCP_DSACK_SEEN;
}
-/* Initialize metrics on socket. */
-
-static void tcp_init_metrics(struct sock *sk)
-{
- struct tcp_sock *tp = tcp_sk(sk);
- struct dst_entry *dst = __sk_dst_get(sk);
-
- if (dst == NULL)
- goto reset;
-
- dst_confirm(dst);
-
- if (dst_metric_locked(dst, RTAX_CWND))
- tp->snd_cwnd_clamp = dst_metric(dst, RTAX_CWND);
- if (dst_metric(dst, RTAX_SSTHRESH)) {
- tp->snd_ssthresh = dst_metric(dst, RTAX_SSTHRESH);
- if (tp->snd_ssthresh > tp->snd_cwnd_clamp)
- tp->snd_ssthresh = tp->snd_cwnd_clamp;
- } else {
- /* ssthresh may have been reduced unnecessarily during.
- * 3WHS. Restore it back to its initial default.
- */
- tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
- }
- if (dst_metric(dst, RTAX_REORDERING) &&
- tp->reordering != dst_metric(dst, RTAX_REORDERING)) {
- tcp_disable_fack(tp);
- tcp_disable_early_retrans(tp);
- tp->reordering = dst_metric(dst, RTAX_REORDERING);
- }
-
- if (dst_metric(dst, RTAX_RTT) == 0 || tp->srtt == 0)
- goto reset;
-
- /* Initial rtt is determined from SYN,SYN-ACK.
- * The segment is small and rtt may appear much
- * less than real one. Use per-dst memory
- * to make it more realistic.
- *
- * A bit of theory. RTT is time passed after "normal" sized packet
- * is sent until it is ACKed. In normal circumstances sending small
- * packets force peer to delay ACKs and calculation is correct too.
- * The algorithm is adaptive and, provided we follow specs, it
- * NEVER underestimate RTT. BUT! If peer tries to make some clever
- * tricks sort of "quick acks" for time long enough to decrease RTT
- * to low value, and then abruptly stops to do it and starts to delay
- * ACKs, wait for troubles.
- */
- if (dst_metric_rtt(dst, RTAX_RTT) > tp->srtt) {
- tp->srtt = dst_metric_rtt(dst, RTAX_RTT);
- tp->rtt_seq = tp->snd_nxt;
- }
- if (dst_metric_rtt(dst, RTAX_RTTVAR) > tp->mdev) {
- tp->mdev = dst_metric_rtt(dst, RTAX_RTTVAR);
- tp->mdev_max = tp->rttvar = max(tp->mdev, tcp_rto_min(sk));
- }
- tcp_set_rto(sk);
-reset:
- if (tp->srtt == 0) {
- /* RFC6298: 5.7 We've failed to get a valid RTT sample from
- * 3WHS. This is most likely due to retransmission,
- * including spurious one. Reset the RTO back to 3secs
- * from the more aggressive 1sec to avoid more spurious
- * retransmission.
- */
- tp->mdev = tp->mdev_max = tp->rttvar = TCP_TIMEOUT_FALLBACK;
- inet_csk(sk)->icsk_rto = TCP_TIMEOUT_FALLBACK;
- }
- /* Cut cwnd down to 1 per RFC5681 if SYN or SYN-ACK has been
- * retransmitted. In light of RFC6298 more aggressive 1sec
- * initRTO, we only reset cwnd when more than 1 SYN/SYN-ACK
- * retransmission has occurred.
- */
- if (tp->total_retrans > 1)
- tp->snd_cwnd = 1;
- else
- tp->snd_cwnd = tcp_init_cwnd(tp, dst);
- tp->snd_cwnd_stamp = tcp_time_stamp;
-}
-
static void tcp_update_reordering(struct sock *sk, const int metric,
const int ts)
{