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Message-Id: <20120710.080708.201390738580969426.davem@davemloft.net>
Date: Tue, 10 Jul 2012 08:07:08 -0700 (PDT)
From: David Miller <davem@...emloft.net>
To: netdev@...r.kernel.org
Subject: [PATCH 01/16] tcp: Move dynamnic metrics handling into seperate
file.
Signed-off-by: David S. Miller <davem@...emloft.net>
---
include/net/tcp.h | 4 +
net/ipv4/Makefile | 2 +-
net/ipv4/tcp_input.c | 188 +----------------------------------------------
net/ipv4/tcp_metrics.c | 192 ++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 199 insertions(+), 187 deletions(-)
create mode 100644 net/ipv4/tcp_metrics.c
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 53fb7d8..98ca797 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -388,6 +388,8 @@ extern void tcp_enter_frto(struct sock *sk);
extern void tcp_enter_loss(struct sock *sk, int how);
extern void tcp_clear_retrans(struct tcp_sock *tp);
extern void tcp_update_metrics(struct sock *sk);
+extern void tcp_init_metrics(struct sock *sk);
+extern void tcp_disable_fack(struct tcp_sock *tp);
extern void tcp_close(struct sock *sk, long timeout);
extern void tcp_init_sock(struct sock *sk);
extern unsigned int tcp_poll(struct file * file, struct socket *sock,
@@ -556,6 +558,8 @@ static inline u32 __tcp_set_rto(const struct tcp_sock *tp)
return (tp->srtt >> 3) + tp->rttvar;
}
+extern void tcp_set_rto(struct sock *sk);
+
static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
{
tp->pred_flags = htonl((tp->tcp_header_len << 26) |
diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
index ff75d3b..5a23e8b 100644
--- a/net/ipv4/Makefile
+++ b/net/ipv4/Makefile
@@ -7,7 +7,7 @@ obj-y := route.o inetpeer.o protocol.o \
ip_output.o ip_sockglue.o inet_hashtables.o \
inet_timewait_sock.o inet_connection_sock.o \
tcp.o tcp_input.o tcp_output.o tcp_timer.o tcp_ipv4.o \
- tcp_minisocks.o tcp_cong.o \
+ tcp_minisocks.o tcp_cong.o tcp_metrics.o \
datagram.o raw.o udp.o udplite.o \
arp.o icmp.o devinet.o af_inet.o igmp.o \
fib_frontend.o fib_semantics.o fib_trie.o \
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index ca0d0e7..055ac49 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)
{
diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c
new file mode 100644
index 0000000..2793ecf
--- /dev/null
+++ b/net/ipv4/tcp_metrics.c
@@ -0,0 +1,192 @@
+#include <linux/cache.h>
+#include <linux/tcp.h>
+
+#include <net/inet_connection_sock.h>
+#include <net/sock.h>
+#include <net/dst.h>
+#include <net/tcp.h>
+
+int sysctl_tcp_nometrics_save __read_mostly;
+
+/* 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);
+ }
+ }
+}
+
+/* Initialize metrics on socket. */
+
+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;
+}
--
1.7.10.4
--
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