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Date: Sat, 17 Oct 2009 17:20:30 +0300 (EEST)
From: Julian Anastasov <ja@....bg>
To: Eric Dumazet <eric.dumazet@...il.com>
cc: Willy Tarreau <w@....eu>, David Miller <davem@...emloft.net>,
netdev@...r.kernel.org
Subject: Re: TCP_DEFER_ACCEPT is missing counter update
Hello,
On Sat, 17 Oct 2009, Eric Dumazet wrote:
> I really like this, but please define helper functions out of do_tcp_setsockopt()
>
> /* Translate value in seconds to number of SYN-ACK retransmits */
> static u8 secs_to_retrans(int seconds)
> {
> u8 res = 0;
>
> if (seconds > 0) {
> int timeout = TCP_TIMEOUT_INIT / HZ;
> int period = timeout;
>
> res = 1;
> while (res < 255 && seconds > period) {
> res++;
> timeout <<= 1;
> if (timeout > TCP_RTO_MAX / HZ)
> timeout = TCP_RTO_MAX / HZ;
> period += timeout;
> }
> }
> return res;
> }
>
> You also need the reverse function for getsockopt()...
Yes, I forgot that. Here is what I tested, should
I split it later to 2 patches? May be it should go somewhere
in net/core/sock.c as extern funcs with EXPORT_SYMBOL to
allow other protocols one day to use it?
Signed-off-by: Julian Anastasov <ja@....bg>
diff -urp v2.6.31/linux/net/ipv4/tcp.c linux/net/ipv4/tcp.c
--- v2.6.31/linux/net/ipv4/tcp.c 2009-09-11 10:27:17.000000000 +0300
+++ linux/net/ipv4/tcp.c 2009-10-17 16:37:48.000000000 +0300
@@ -326,6 +326,43 @@ void tcp_enter_memory_pressure(struct so
EXPORT_SYMBOL(tcp_enter_memory_pressure);
+/* Convert seconds to retransmits based on initial and max timeout */
+static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
+{
+ u8 res = 0;
+
+ if (seconds > 0) {
+ int period = timeout;
+
+ res = 1;
+ while (seconds > period && res < 255) {
+ res++;
+ timeout <<= 1;
+ if (timeout > rto_max)
+ timeout = rto_max;
+ period += timeout;
+ }
+ }
+ return res;
+}
+
+/* Convert retransmits to seconds based on initial and max timeout */
+static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
+{
+ int period = 0;
+
+ if (retrans > 0) {
+ period = timeout;
+ while (--retrans) {
+ timeout <<= 1;
+ if (timeout > rto_max)
+ timeout = rto_max;
+ period += timeout;
+ }
+ }
+ return period;
+}
+
/*
* Wait for a TCP event.
*
@@ -2163,16 +2200,10 @@ static int do_tcp_setsockopt(struct sock
break;
case TCP_DEFER_ACCEPT:
- icsk->icsk_accept_queue.rskq_defer_accept = 0;
- if (val > 0) {
- /* Translate value in seconds to number of
- * retransmits */
- while (icsk->icsk_accept_queue.rskq_defer_accept < 32 &&
- val > ((TCP_TIMEOUT_INIT / HZ) <<
- icsk->icsk_accept_queue.rskq_defer_accept))
- icsk->icsk_accept_queue.rskq_defer_accept++;
- icsk->icsk_accept_queue.rskq_defer_accept++;
- }
+ /* Translate value in seconds to number of retransmits */
+ icsk->icsk_accept_queue.rskq_defer_accept =
+ secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
+ TCP_RTO_MAX / HZ);
break;
case TCP_WINDOW_CLAMP:
@@ -2353,8 +2384,8 @@ static int do_tcp_getsockopt(struct sock
val = (val ? : sysctl_tcp_fin_timeout) / HZ;
break;
case TCP_DEFER_ACCEPT:
- val = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 :
- ((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1));
+ val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
+ TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
break;
case TCP_WINDOW_CLAMP:
val = tp->window_clamp;
Regards
--
Julian Anastasov <ja@....bg>
--
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