[PATCH v2] sctp: Add buffer utilization fields to /proc/net/sctp/assocs

[PATCH v2] sctp: Add buffer utilization fields to /proc/net/sctp/assocs

[Dilip Daya]

From: Dilip Daya <dilip.daya@hp.com>

sctp: Add buffer utilization fields to /proc/net/sctp/assocs

This patch adds the following fields to /proc/net/sctp/assocs output:

	- sk->sk_wmem_alloc    (transmit queue bytes committed)
	- sk->sk_wmem_queued   (persistent queue size)
	- sk->sk_sndbuf        (size of send buffer in bytes)
	- sk->sk_rcvbuf        (size of receive buffer in bytes)

Patch applies to v3.8.6 and v3.9-rc6.

When small DATA chunks containing 136 bytes data are sent the TX_QUEUE
(assoc->sndbuf_used) reaches a maximum of 40.9% of sk_sndbuf value when
peer.rwnd = 0. This was diagnosed from sk_wmem_alloc value reaching maximum
value of sk_sndbuf.

TX_QUEUE (assoc->sndbuf_used), sk_wmem_alloc and sk_wmem_queued values are
incremented in sctp_set_owner_w() for outgoing data chunks. Having access to
the above values in /proc/net/sctp/assocs will provide a better understanding
of SCTP buffer management.

With patch applied, example output when peer.rwnd = 0

where:
    ASSOC ffff880132298000 is sender
          ffff880125343000 is receiver

 ASSOC           SOCK            STY SST ST  HBKT ASSOC-ID TX_QUEUE RX_QUEUE \
ffff880132298000 ffff880124a0a0c0 2   1   3  29325    1      214656        0 \
ffff880125343000 ffff8801237d7700 2   1   3  36210    2           0   524520 \

UID   INODE LPORT  RPORT LADDRS <-> RADDRS       HBINT   INS  OUTS \
  0   25108 3455   3456  *10.4.8.3 <-> *10.5.8.3  7500     2     2 \
  0   27819 3456   3455  *10.5.8.3 <-> *10.4.8.3  7500     2     2 \

MAXRT T1X  T2X     RTXC sk_wmem_alloc sk_wmem_queued sk_sndbuf sk_rcvbuf
    4   0   0        72      525633         440320      524288    524288
    4   0   0         0           1              0      524288    524288

v2: Not changing spacing between the fields.

Signed-off-by: Dilip Daya <dilip.daya@hp.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
---
 net/sctp/proc.c |   12 +++++++++---
 1 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/net/sctp/proc.c b/net/sctp/proc.c
index ab3bba8..80175cd 100644
--- a/net/sctp/proc.c
+++ b/net/sctp/proc.c
@@ -295,7 +295,8 @@ static void * sctp_assocs_seq_start(struct seq_file *seq, loff_t *pos)
 		seq_printf(seq, " ASSOC     SOCK   STY SST ST HBKT "
 				"ASSOC-ID TX_QUEUE RX_QUEUE UID INODE LPORT "
 				"RPORT LADDRS <-> RADDRS "
-				"HBINT INS OUTS MAXRT T1X T2X RTXC\n");
+				"HBINT INS OUTS MAXRT T1X T2X RTXC "
+				"sk_wmem_alloc sk_wmem_queued sk_sndbuf sk_rcvbuf\n");
 
 	return (void *)pos;
 }
@@ -349,11 +350,16 @@ static int sctp_assocs_seq_show(struct seq_file *seq, void *v)
 		sctp_seq_dump_local_addrs(seq, epb);
 		seq_printf(seq, "<-> ");
 		sctp_seq_dump_remote_addrs(seq, assoc);
-		seq_printf(seq, "\t%8lu %5d %5d %4d %4d %4d %8d ",
+		seq_printf(seq, "\t%8lu %5d %5d %4d %4d %4d %8d "
+						"%8d %8d %8d %8d",
 			assoc->hbinterval, assoc->c.sinit_max_instreams,
 			assoc->c.sinit_num_ostreams, assoc->max_retrans,
 			assoc->init_retries, assoc->shutdown_retries,
-			assoc->rtx_data_chunks);
+			assoc->rtx_data_chunks,
+			atomic_read(&sk->sk_wmem_alloc),
+			sk->sk_wmem_queued,
+			sk->sk_sndbuf,
+			sk->sk_rcvbuf);
 		seq_printf(seq, "\n");
 	}
 	read_unlock(&head->lock);
-- 
1.5.6.5

Re: [PATCH v2] sctp: Add buffer utilization fields to /proc/net/sctp/assocs

[David Miller]

From: Dilip Daya <dilip.daya@hp.com>
Date: Thu, 11 Apr 2013 15:49:56 -0400

> From: Dilip Daya <dilip.daya@hp.com>
> 
> sctp: Add buffer utilization fields to /proc/net/sctp/assocs
> 
> This patch adds the following fields to /proc/net/sctp/assocs output:
> 
> 	- sk->sk_wmem_alloc    (transmit queue bytes committed)
> 	- sk->sk_wmem_queued   (persistent queue size)
> 	- sk->sk_sndbuf        (size of send buffer in bytes)
> 	- sk->sk_rcvbuf        (size of receive buffer in bytes)

Please use smaller field names, perhaps "wmema wmemq sndbuf rcvbuf"

> Patch applies to v3.8.6 and v3.9-rc6.

This does not belong in the commit message proper, it belongs in the
ancillary information you provide after the "---" delimeter.

> v2: Not changing spacing between the fields.

Similarly this supplemental information belongs after "---"

> +		seq_printf(seq, "\t%8lu %5d %5d %4d %4d %4d %8d "
> +						"%8d %8d %8d %8d",

This is not indented properly, the second line should have the "
appearing at the first column after the openning parenthesis
of the seq_printf() call.

The goal is not to exclusively use TAB characters to indent the
line into outer space, the goal is to use the appropriate of
TAB, then space, characters as necessary to indent the code to
the correct column.