On Fri, Sep 12, 2008 at 09:12:07AM -0400, Jeff Layton wrote:
> I got a bug report from a user who got this message in his logs:
>
> lockd: too many open TCP sockets, consider increasing number of nfsd
> threads.
>
> ...lockd also started refusing connections at this point. He was
> apparently doing some testing with a highly contended lock. lockd
> started refusing connections after the first 80 and started printing
> this warning. He tried increasing the number of nfsd threads, which of
> course didn't do any good. This patch removes the "nfsd" from the
> message to make this a little less confusing.
>
> There is still an artificial limit of 80 concurrent clients with lockd.
> svc_check_conn_limits has this hardcoded check:
>
> if (serv->sv_tmpcnt > (serv->sv_nrthreads+3)*20) {
>
> ...my feeling is that we need to either raise the number or eliminate
> this check for single-threaded services like lockd. I'd first like to
> understand the rationale for setting the limit here, however. Can anyone
> clarify?
No idea, but yes, this is a problem.
Brainstorming other options:
- add a new sv_maxconnections field, give it a better default,
and maybe make it tunable some day? (Oh goody, another knob
to twiddle).
- implement the suggestion in the comment above this function
and limit connections per ip address. I guess the idea would
be to prevent a single buggy client from bringing everyone
down. Is that really likely? Results in the presence of NAT
could be hard to debug.
- Base the limit on available memory instead of number of
threads?
- Kill the check entirely? It'd help to know whether it was
originally prompted by some specific situation....
--b.
>
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> net/sunrpc/svc_xprt.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
> index bf5b5cd..340f549 100644
> --- a/net/sunrpc/svc_xprt.c
> +++ b/net/sunrpc/svc_xprt.c
> @@ -536,7 +536,7 @@ static void svc_check_conn_limits(struct svc_serv *serv)
> /* Try to help the admin */
> printk(KERN_NOTICE "%s: too many open "
> "connections, consider increasing the "
> - "number of nfsd threads\n",
> + "number of threads\n",
> serv->sv_name);
> }
> /*
> --
> 1.5.5.1
>
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