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Message-ID: <27e0e16b438b67fef765ea03812d6e97646bc1f0.camel@kernel.org>
Subject: Re: [PATCH] fs: nfsd: use group allocation/free of per-cpu counters
 API
From: Jeff Layton <jlayton@kernel.org>
To: Kefeng Wang <wangkefeng.wang@huawei.com>, Chuck Lever
 <chuck.lever@oracle.com>, Neil Brown <neilb@suse.de>, Olga Kornievskaia
 <kolga@netapp.com>, Dai Ngo <Dai.Ngo@oracle.com>, Tom Talpey
 <tom@talpey.com>,  Dennis Zhou <dennis@kernel.org>
Cc: linux-nfs@vger.kernel.org
Date: Mon, 25 Mar 2024 06:52:06 -0400
In-Reply-To: <20240325041019.52998-1-wangkefeng.wang@huawei.com>
References: <20240325041019.52998-1-wangkefeng.wang@huawei.com>
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On Mon, 2024-03-25 at 12:10 +0800, Kefeng Wang wrote:
> Use group allocation/free of per-cpu counters api to accelerate
> nfsd_percpu_counters_init/destroy() and simplify code.
>=20
> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> ---
>  fs/nfsd/stats.c | 18 ++----------------
>  1 file changed, 2 insertions(+), 16 deletions(-)
>=20
> diff --git a/fs/nfsd/stats.c b/fs/nfsd/stats.c
> index be52fb1e928e..c7f481d180f8 100644
> --- a/fs/nfsd/stats.c
> +++ b/fs/nfsd/stats.c
> @@ -75,18 +75,7 @@ DEFINE_PROC_SHOW_ATTRIBUTE(nfsd);
> =20
>  int nfsd_percpu_counters_init(struct percpu_counter *counters, int num)
>  {
> -	int i, err =3D 0;
> -
> -	for (i =3D 0; !err && i < num; i++)
> -		err =3D percpu_counter_init(&counters[i], 0, GFP_KERNEL);
> -
> -	if (!err)
> -		return 0;
> -
> -	for (; i > 0; i--)
> -		percpu_counter_destroy(&counters[i-1]);
> -
> -	return err;
> +	return percpu_counter_init_many(counters, 0, GFP_KERNEL, num);
>  }
> =20
>  void nfsd_percpu_counters_reset(struct percpu_counter counters[], int nu=
m)
> @@ -99,10 +88,7 @@ void nfsd_percpu_counters_reset(struct percpu_counter =
counters[], int num)
> =20
>  void nfsd_percpu_counters_destroy(struct percpu_counter counters[], int =
num)
>  {
> -	int i;
> -
> -	for (i =3D 0; i < num; i++)
> -		percpu_counter_destroy(&counters[i]);
> +	percpu_counter_destroy_many(counters, num);
>  }
> =20
>  int nfsd_stat_counters_init(struct nfsd_net *nn)

I think it would be simpler to eliminate
nfsd_percpu_counters_init/_destroy altogether and just replace them with
percpu_counter_*_many calls. Is there any reason not to do that?

--=20
Jeff Layton <jlayton@kernel.org>