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

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Message-ID: <bb9c7c2c53d5a4196ceb0ec81dcee747dd7df5e9.camel@kernel.org>
Date: Wed, 04 Feb 2026 14:13:17 -0500
From: Jeff Layton <jlayton@...nel.org>
To: Chuck Lever <cel@...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, 2026-02-04 at 13:51 -0500, Chuck Lever wrote:
> 
> 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"
> 

Ok, I'll do that for v2.

Thanks,
-- 
Jeff Layton <jlayton@...nel.org>