On Thu, 2024-03-07 at 16:39 -0500, trondmy@xxxxxxxxx wrote:
> From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
>
> When creating a listener socket to be handed to /proc/fs/nfsd/portlist,
> we currently limit the number of backlogged connections to 64. Since
> that value was chosen in 2006, the scale at which data centres operate
> has changed significantly. Given a modern server with many thousands of
> clients, a limit of 64 connections can create bottlenecks, particularly
> at at boot time.
> By converting to using an argument of -1, we allow the backlog to be set
> by the default value in /proc/sys/net/core/somaxconn.
>
> Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
> ---
> utils/nfsd/nfssvc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/utils/nfsd/nfssvc.c b/utils/nfsd/nfssvc.c
> index 46452d972407..c781054dbdae 100644
> --- a/utils/nfsd/nfssvc.c
> +++ b/utils/nfsd/nfssvc.c
> @@ -205,7 +205,7 @@ nfssvc_setfds(const struct addrinfo *hints, const char *node, const char *port)
> rc = errno;
> goto error;
> }
> - if (addr->ai_protocol == IPPROTO_TCP && listen(sockfd, 64)) {
> + if (addr->ai_protocol == IPPROTO_TCP && listen(sockfd, -1)) {
> xlog(L_ERROR, "unable to create listening socket: "
> "errno %d (%m)", errno);
> rc = errno;
It does look like the kernel casts the value to unsigned int before
trying to interpret it, but that doesn't seem to be documented anywhere
that I can find. It's certainly not in the manpage
There is this in /usr/include/bits/socket.h:
/* Maximum queue length specifiable by listen. */
#define SOMAXCONN 4096
...but I guess that's problematic if you set "somaxconn" sysctl higher.
I wonder if SOMAXCONN should be redefined as "(int)UINT_MAX" in the UAPI
headers?
--
Jeff Layton <jlayton@xxxxxxxxxx>
