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From:   Chuck Lever III <chuck.lever@oracle.com>
To:     Dai Ngo <dai.ngo@oracle.com>
CC:     "jlayton@kernel.org" <jlayton@kernel.org>,
        Linux NFS Mailing List <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH v4 1/2] NFSD: keep track of the number of courtesy clients
 in the system
Thread-Topic: [PATCH v4 1/2] NFSD: keep track of the number of courtesy
 clients in the system
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Date:   Wed, 31 Aug 2022 14:30:39 +0000
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> On Aug 30, 2022, at 5:48 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>=20
> Add counter nfs4_courtesy_client_count to nfsd_net to keep track
> of the number of courtesy clients in the system.
>=20
> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
> ---
> fs/nfsd/netns.h     |  2 ++
> fs/nfsd/nfs4state.c | 13 ++++++++++++-
> 2 files changed, 14 insertions(+), 1 deletion(-)
>=20
> diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h
> index ffe17743cc74..2695dff1378a 100644
> --- a/fs/nfsd/netns.h
> +++ b/fs/nfsd/netns.h
> @@ -192,6 +192,8 @@ struct nfsd_net {
>=20
> 	atomic_t		nfs4_client_count;
> 	int			nfs4_max_clients;
> +
> +	atomic_t		nfsd_courtesy_client_count;

See comment for 2/2: rename this variable?


> };
>=20
> /* Simple check to find out if a given net was properly initialized */
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index c5d199d7e6b4..eaf7b4dcea33 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -169,6 +169,8 @@ static __be32 get_client_locked(struct nfs4_client *c=
lp)
> 	if (is_client_expired(clp))
> 		return nfserr_expired;
> 	atomic_inc(&clp->cl_rpc_users);
> +	if (clp->cl_state !=3D NFSD4_ACTIVE)
> +		atomic_add_unless(&nn->nfsd_courtesy_client_count, -1, 0);

This appears to be a common bit of logic. Create a helper for it?


> 	clp->cl_state =3D NFSD4_ACTIVE;
> 	return nfs_ok;
> }
> @@ -190,6 +192,8 @@ renew_client_locked(struct nfs4_client *clp)
>=20
> 	list_move_tail(&clp->cl_lru, &nn->client_lru);
> 	clp->cl_time =3D ktime_get_boottime_seconds();
> +	if (clp->cl_state !=3D NFSD4_ACTIVE)
> +		atomic_add_unless(&nn->nfsd_courtesy_client_count, -1, 0);
> 	clp->cl_state =3D NFSD4_ACTIVE;
> }
>=20
> @@ -2233,6 +2237,8 @@ __destroy_client(struct nfs4_client *clp)
> 	if (clp->cl_cb_conn.cb_xprt)
> 		svc_xprt_put(clp->cl_cb_conn.cb_xprt);
> 	atomic_add_unless(&nn->nfs4_client_count, -1, 0);
> +	if (clp->cl_state !=3D NFSD4_ACTIVE)
> +		atomic_add_unless(&nn->nfsd_courtesy_client_count, -1, 0);
> 	free_client(clp);
> 	wake_up_all(&expiry_wq);
> }
> @@ -4356,6 +4362,8 @@ void nfsd4_init_leases_net(struct nfsd_net *nn)
> 	max_clients =3D (u64)si.totalram * si.mem_unit / (1024 * 1024 * 1024);
> 	max_clients *=3D NFS4_CLIENTS_PER_GB;
> 	nn->nfs4_max_clients =3D max_t(int, max_clients, NFS4_CLIENTS_PER_GB);
> +
> +	atomic_set(&nn->nfsd_courtesy_client_count, 0);
> }
>=20
> static void init_nfs4_replay(struct nfs4_replay *rp)
> @@ -5878,8 +5886,11 @@ nfs4_get_client_reaplist(struct nfsd_net *nn, stru=
ct list_head *reaplist,
> 			goto exp_client;
> 		if (!state_expired(lt, clp->cl_time))
> 			break;
> -		if (!atomic_read(&clp->cl_rpc_users))
> +		if (!atomic_read(&clp->cl_rpc_users)) {
> +			if (clp->cl_state =3D=3D NFSD4_ACTIVE)
> +				atomic_inc(&nn->nfsd_courtesy_client_count);
> 			clp->cl_state =3D NFSD4_COURTESY;
> +		}
> 		if (!client_has_state(clp))
> 			goto exp_client;
> 		if (!nfs4_anylock_blockers(clp))
> --=20
> 2.9.5
>=20

--
Chuck Lever