Thread (14 messages) 14 messages, 6 authors, 2012-02-01

Re: [PATCH] net: Disambiguate kernel message

From: Arun Sharma <hidden>
Date: 2012-01-31 18:15:59
Also in: lkml
Subsystem: networking [general], networking [tcp], the rest · Maintainers: "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Neal Cardwell, Linus Torvalds

On Mon, Jan 30, 2012 at 08:22:03PM -0800, Bjorn Helgaas wrote:
quoted
We print a different message depending on whether we're out
of TCP memory or there are too many orphan sockets.
This patch mentions pairs of messages that are almost the same, but
not quite.  If they're supposed to be different, I'd suggest making
them clearly different.  As it is, the differences look like careless
mistakes:
Good point. Updated patch changes the existing printks to be
the same as well.

On 1/31/12 12:51 AM, Christoph Paasch wrote:
quoted
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2015,10 +2015,22 @@ adjudge_to_death:
  	}
  	if (sk->sk_state != TCP_CLOSE) {
  		sk_mem_reclaim(sk);
-		if (tcp_too_many_orphans(sk, 0)) {
+		bool too_many_orphans = tcp_too_many_orphans(sk, 0);
+		bool out_of_socket_memory = tcp_out_of_memory(sk);
This introduces a compiler warning because you have the declarations
after the code (sk_mem_reclaim()):
Fixed by the patch below.

 -Arun
From 505717e51b15304b0bf50fc9dfed43fd06fad09a Mon Sep 17 00:00:00 2001
From: Arun Sharma <redacted>
Date: Mon, 30 Jan 2012 14:16:06 -0800
Subject: [PATCH] net: Disambiguate kernel message

Some of our machines were reporting:

TCP: too many of orphaned sockets

even when the number of orphaned sockets was well below the
limit.

We print a different message depending on whether we're out
of TCP memory or there are too many orphaned sockets.

Signed-off-by: Arun Sharma <redacted>
Suggested-by: Mohan Srinivasan <redacted>
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: David Miller <davem@davemloft.net>
Cc: Glauber Costa <redacted>
Cc: Ingo Molnar <redacted>
---
 include/net/tcp.h    |   12 ++++++++----
 net/ipv4/tcp.c       |   17 +++++++++++++++--
 net/ipv4/tcp_timer.c |   12 +++++++++---
 3 files changed, 32 insertions(+), 9 deletions(-)
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 0118ea9..92965dd 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -273,6 +273,14 @@ static inline int between(__u32 seq1, __u32 seq2, __u32 seq3)
 	return seq3 - seq2 >= seq1 - seq2;
 }
 
+static inline bool tcp_out_of_memory(struct sock *sk)
+{
+	if (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
+	    sk_memory_allocated(sk) > sk_prot_mem_limits(sk, 2))
+		return true;
+	return false;
+}
+
 static inline bool tcp_too_many_orphans(struct sock *sk, int shift)
 {
 	struct percpu_counter *ocp = sk->sk_prot->orphan_count;
@@ -283,10 +291,6 @@ static inline bool tcp_too_many_orphans(struct sock *sk, int shift)
 		if (orphans << shift > sysctl_tcp_max_orphans)
 			return true;
 	}
-
-	if (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
-	    sk_memory_allocated(sk) > sk_prot_mem_limits(sk, 2))
-		return true;
 	return false;
 }
 
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 9bcdec3..27de5e4 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2014,11 +2014,24 @@ adjudge_to_death:
 		}
 	}
 	if (sk->sk_state != TCP_CLOSE) {
+		bool too_many_orphans, out_of_socket_memory;
+
 		sk_mem_reclaim(sk);
-		if (tcp_too_many_orphans(sk, 0)) {
+		too_many_orphans = tcp_too_many_orphans(sk, 0);
+		out_of_socket_memory = tcp_out_of_memory(sk);
+		if (too_many_orphans) {
 			if (net_ratelimit())
-				printk(KERN_INFO "TCP: too many of orphaned "
+				printk(KERN_INFO "TCP: too many orphaned "
 				       "sockets\n");
+		}
+
+		if (out_of_socket_memory) {
+			if (net_ratelimit())
+				printk(KERN_INFO "TCP: out of memory. "
+				       "Consider tuning tcp_mem\n");
+		}
+
+		if (too_many_orphans || out_of_socket_memory) {
 			tcp_set_state(sk, TCP_CLOSE);
 			tcp_send_active_reset(sk, GFP_ATOMIC);
 			NET_INC_STATS_BH(sock_net(sk),
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index a516d1e..0ac006b 100644
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -67,6 +67,7 @@ static int tcp_out_of_resources(struct sock *sk, int do_reset)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 	int shift = 0;
+	bool too_many_orphans, out_of_socket_memory;
 
 	/* If peer does not open window for long time, or did not transmit
 	 * anything for long time, penalize it. */
@@ -77,9 +78,14 @@ static int tcp_out_of_resources(struct sock *sk, int do_reset)
 	if (sk->sk_err_soft)
 		shift++;
 
-	if (tcp_too_many_orphans(sk, shift)) {
-		if (net_ratelimit())
-			printk(KERN_INFO "Out of socket memory\n");
+	too_many_orphans = tcp_too_many_orphans(sk, shift);
+	out_of_socket_memory = tcp_out_of_memory(sk);
+	if (too_many_orphans || out_of_socket_memory) {
+		if (out_of_socket_memory && net_ratelimit())
+			printk(KERN_INFO "TCP: out of memory. "
+					 "Consider tuning tcp_mem\n");
+		if (too_many_orphans && net_ratelimit())
+			printk(KERN_INFO "TCP: too many orphaned sockets\n");
 
 		/* Catch exceptional cases, when connection requires reset.
 		 *      1. Last segment was sent recently. */
-- 
1.7.4
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