linux/arch/mn10300
Neil Horman 3b885787ea net: Generalize socket rx gap / receive queue overflow cmsg
Create a new socket level option to report number of queue overflows

Recently I augmented the AF_PACKET protocol to report the number of frames lost
on the socket receive queue between any two enqueued frames.  This value was
exported via a SOL_PACKET level cmsg.  AFter I completed that work it was
requested that this feature be generalized so that any datagram oriented socket
could make use of this option.  As such I've created this patch, It creates a
new SOL_SOCKET level option called SO_RXQ_OVFL, which when enabled exports a
SOL_SOCKET level cmsg that reports the nubmer of times the sk_receive_queue
overflowed between any two given frames.  It also augments the AF_PACKET
protocol to take advantage of this new feature (as it previously did not touch
sk->sk_drops, which this patch uses to record the overflow count).  Tested
successfully by me.

Notes:

1) Unlike my previous patch, this patch simply records the sk_drops value, which
is not a number of drops between packets, but rather a total number of drops.
Deltas must be computed in user space.

2) While this patch currently works with datagram oriented protocols, it will
also be accepted by non-datagram oriented protocols. I'm not sure if thats
agreeable to everyone, but my argument in favor of doing so is that, for those
protocols which aren't applicable to this option, sk_drops will always be zero,
and reporting no drops on a receive queue that isn't used for those
non-participating protocols seems reasonable to me.  This also saves us having
to code in a per-protocol opt in mechanism.

3) This applies cleanly to net-next assuming that commit
977750076d (my af packet cmsg patch) is reverted

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-10-12 13:26:31 -07:00
..
boot
configs MN10300: Update the ASB2303 defconfig 2009-04-24 07:47:59 -07:00
include/asm net: Generalize socket rx gap / receive queue overflow cmsg 2009-10-12 13:26:31 -07:00
kernel mn10300: Clean up linker script using higher-level macros. 2009-09-24 17:16:22 -07:00
lib
mm arches: drop superfluous casts in nr_free_pages() callers 2009-09-22 07:17:34 -07:00
oprofile MN10300: Kill MN10300's own profiling Kconfig 2009-04-09 10:53:16 -07:00
proc-mn103e010 Separate out the proc- and unit-specific header directories from the general 2009-04-10 14:33:48 +01:00
unit-asb2303 mn10300: fix kernel build failures when using gcc-4.x 2009-10-01 16:11:12 -07:00
unit-asb2305 mn10300: fix kernel build failures when using gcc-4.x 2009-10-01 16:11:12 -07:00
Kconfig MN10300: Add utrace/tracehooks support 2009-06-11 09:02:20 -07:00
Kconfig.debug
Makefile Separate out the proc- and unit-specific header directories from the general 2009-04-10 14:33:48 +01:00