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SubjectRe: [PATCH] net: Disambiguate kernel message
On Mon, Jan 30, 2012 at 08:22:03PM -0800, Bjorn Helgaas wrote:
> > 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:

>> --- 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 <asharma@fb.com>
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 <asharma@fb.com>
Suggested-by: Mohan Srinivasan <mohan@fb.com>
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: David Miller <davem@davemloft.net>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Ingo Molnar <mingo@elte.hu>
---
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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