Re: [PATCHv2 RFC] RTEXT_FILTER_SKIP_STATS support to avoid dumping inet/inet6 stats

[Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>]

On 09/11/2015 03:04 AM, Sowmini Varadhan wrote:
>
> Many commonly used functions like getifaddrs() invoke RTM_GETLINK
> to dump the interface information, and do not need the
> the AF_INET6 statististics that are always returned by default
> from rtnl_fill_ifinfo().
>
> Computing the statistics can be an expensive operation that impacts
> scaling, so it is desirable to avoid this if the information is
> not needed.
>
> This patch adds a the RTEXT_FILTER_SKIP_STATS extended info flag that
> can be passed with netlink_request() to avoid statistics computation
> for the ifinfo path.
>
> Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
> ---
> v2: David Miller comments: pass u32 ext_filter_mask down.
>
>   include/net/rtnetlink.h        |    3 ++-
>   include/uapi/linux/rtnetlink.h |    1 +
>   net/core/rtnetlink.c           |    2 +-
>   net/ipv4/devinet.c             |    3 ++-
>   net/ipv6/addrconf.c            |   13 +++++++++----
>   5 files changed, 15 insertions(+), 7 deletions(-)

Sowmini, Thanks for the patch which is more cleaner way without
breaking current behaviour.

[ Though RTEXT_FILTER_NEED_STATS flag with reverse effect  would have
helped immediately :)]

/me waits for the RTEXT_FILTER_SKIP_STATS to be supported in
gccgo/golang, so that it can be used in docker newNetlinkRequest() to
exploit this.