linux-kernel - Re: [PATCH] nfsd: report the requested maximum number of threads instead of number running

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Message-Id: <2abf7a33-789f-405d-8993-8fbf30153aaa@app.fastmail.com>
Date: Wed, 04 Feb 2026 13:51:17 -0500
From: "Chuck Lever" <cel@...nel.org>
To: "Jeff Layton" <jlayton@...nel.org>,
 "Chuck Lever" <chuck.lever@...cle.com>, NeilBrown <neil@...wn.name>,
 "Olga Kornievskaia" <okorniev@...hat.com>, "Dai Ngo" <Dai.Ngo@...cle.com>,
 "Tom Talpey" <tom@...pey.com>
Cc: linux-nfs@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] nfsd: report the requested maximum number of threads instead of
 number running



On Wed, Feb 4, 2026, at 12:23 PM, Jeff Layton wrote:
> The current netlink and /proc interfaces deviate from their traditional
> values when dynamic threading is enabled, and there is currently no way
> to know what the current setting is. This patch brings the reporting
> back in line with traditional behavior.
>
> Make these interfaces report the requested maximum number of threads
> instead of the number currently running.
>
> Fixes: d8316b837c2c ("nfsd: add controls to set the minimum number of 
> threads per pool")
> Signed-off-by: Jeff Layton <jlayton@...nel.org>
> ---
> I think this is less surprising than the current behavior of what's in
> Chuck's tree. We could also consider adding netlink attributes to report
> the number of running threads, but you can get that info from ps too.
> ---
>  fs/nfsd/nfsctl.c | 2 +-
>  fs/nfsd/nfssvc.c | 7 ++++---
>  2 files changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
> index 
> 4d8e3c1a7be3b3a4e4f5248b27b60d6b3ae88d51..178c7646b2e25630b85de937d7ced18947c047f9 
> 100644
> --- a/fs/nfsd/nfsctl.c
> +++ b/fs/nfsd/nfsctl.c
> @@ -1700,7 +1700,7 @@ int nfsd_nl_threads_get_doit(struct sk_buff *skb, 
> struct genl_info *info)
>  			struct svc_pool *sp = &nn->nfsd_serv->sv_pools[i];
> 
>  			err = nla_put_u32(skb, NFSD_A_SERVER_THREADS,
> -					  sp->sp_nrthreads);
> +					  sp->sp_nrthrmax);
>  			if (err)
>  				goto err_unlock;
>  		}
> diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
> index 
> 8184514c58de8e396795cd4714a04d66d9637f17..be0add971c2d994948c3e8fca19bcf6f3c75dfaf 
> 100644
> --- a/fs/nfsd/nfssvc.c
> +++ b/fs/nfsd/nfssvc.c
> @@ -239,12 +239,13 @@ static void nfsd_net_free(struct percpu_ref *ref)
> 
>  int nfsd_nrthreads(struct net *net)
>  {
> -	int rv = 0;
> +	int i, rv = 0;
>  	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
> 
>  	mutex_lock(&nfsd_mutex);
>  	if (nn->nfsd_serv)
> -		rv = nn->nfsd_serv->sv_nrthreads;
> +		for (i = 0; i < nn->nfsd_serv->sv_nrpools; ++i)
> +			rv += nn->nfsd_serv->sv_pools[i].sp_nrthrmax;
>  	mutex_unlock(&nfsd_mutex);
>  	return rv;
>  }
> @@ -673,7 +674,7 @@ int nfsd_get_nrthreads(int n, int *nthreads, struct 
> net *net)
> 
>  	if (serv)
>  		for (i = 0; i < serv->sv_nrpools && i < n; i++)
> -			nthreads[i] = serv->sv_pools[i].sp_nrthreads;
> +			nthreads[i] = serv->sv_pools[i].sp_nrthrmax;
>  	return 0;
>  }

AI code review observes that:

The documentation should be updated to reflect that these interfaces
now report the configured maximum threads rather than running threads:

1. Documentation/netlink/specs/nfsd.yaml line 168 - threads-get is
   documented as "get the number of running threads" but now returns
   the configured maximum
2. fs/nfsd/nfsctl.c lines 387-405 - The write_threads() docstring
   says it reports "the number of running NFSD threads" but now
   reports the configured maximum
3. fs/nfsd/nfsctl.c lines 1666-1673 - The nfsd_nl_threads_get_doit()
   docstring says "get the number of running threads"


-- 
Chuck Lever