Re: [PATCH v2] fs: nfsd: use group allocation/free of per-cpu counters API

[Jeff Layton <jlayton@kernel.org>]

On Mon, 2024-03-25 at 21:21 +0800, Kefeng Wang wrote:
> Use group allocation/free of per-cpu counters api to accelerate
> nfsd percpu_counters init/destroy(), and also squash the
> nfsd_percpu_counters_init/reset/destroy() and nfsd_counters_init/destroy()
> into callers to simplify code.
> 
> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> ---
> v2:
> - directly use percpu_counter_*_many helpers and drop wrappers,
>   suggested by Jeff Layton
> 
>  fs/nfsd/export.c | 16 ++++++++++------
>  fs/nfsd/nfsctl.c |  5 +++--
>  fs/nfsd/stats.c  | 42 ------------------------------------------
>  fs/nfsd/stats.h  |  5 -----
>  4 files changed, 13 insertions(+), 55 deletions(-)
> 

An even nicer diffstat!

> diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
> index 7b641095a665..50b3135d07ac 100644
> --- a/fs/nfsd/export.c
> +++ b/fs/nfsd/export.c
> @@ -334,21 +334,25 @@ static void nfsd4_fslocs_free(struct nfsd4_fs_locations *fsloc)
>  static int export_stats_init(struct export_stats *stats)
>  {
>  	stats->start_time = ktime_get_seconds();
> -	return nfsd_percpu_counters_init(stats->counter, EXP_STATS_COUNTERS_NUM);
> +	return percpu_counter_init_many(stats->counter, 0, GFP_KERNEL,
> +					EXP_STATS_COUNTERS_NUM);
>  }
>  
>  static void export_stats_reset(struct export_stats *stats)
>  {
> -	if (stats)
> -		nfsd_percpu_counters_reset(stats->counter,
> -					   EXP_STATS_COUNTERS_NUM);
> +	if (stats) {
> +		int i;
> +
> +		for (i = 0; i < EXP_STATS_COUNTERS_NUM; i++)
> +			percpu_counter_set(&stats->counter[i], 0);
> +	}
>  }
>  
>  static void export_stats_destroy(struct export_stats *stats)
>  {
>  	if (stats)
> -		nfsd_percpu_counters_destroy(stats->counter,
> -					     EXP_STATS_COUNTERS_NUM);
> +		percpu_counter_destroy_many(stats->counter,
> +					    EXP_STATS_COUNTERS_NUM);
>  }
>  
>  static void svc_export_put(struct kref *ref)
> diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
> index ecd18bffeebc..93c87587e646 100644
> --- a/fs/nfsd/nfsctl.c
> +++ b/fs/nfsd/nfsctl.c
> @@ -1672,7 +1672,8 @@ static __net_init int nfsd_net_init(struct net *net)
>  	retval = nfsd_idmap_init(net);
>  	if (retval)
>  		goto out_idmap_error;
> -	retval = nfsd_stat_counters_init(nn);
> +	retval = percpu_counter_init_many(nn->counter, 0, GFP_KERNEL,
> +					  NFSD_STATS_COUNTERS_NUM);
>  	if (retval)
>  		goto out_repcache_error;
>  	memset(&nn->nfsd_svcstats, 0, sizeof(nn->nfsd_svcstats));
> @@ -1704,7 +1705,7 @@ static __net_exit void nfsd_net_exit(struct net *net)
>  	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
>  
>  	nfsd_proc_stat_shutdown(net);
> -	nfsd_stat_counters_destroy(nn);
> +	percpu_counter_destroy_many(nn->counter, NFSD_STATS_COUNTERS_NUM);
>  	nfsd_idmap_shutdown(net);
>  	nfsd_export_shutdown(net);
>  	nfsd_netns_free_versions(nn);
> diff --git a/fs/nfsd/stats.c b/fs/nfsd/stats.c
> index be52fb1e928e..bb22893f1157 100644
> --- a/fs/nfsd/stats.c
> +++ b/fs/nfsd/stats.c
> @@ -73,48 +73,6 @@ static int nfsd_show(struct seq_file *seq, void *v)
>  
>  DEFINE_PROC_SHOW_ATTRIBUTE(nfsd);
>  
> -int nfsd_percpu_counters_init(struct percpu_counter *counters, int num)
> -{
> -	int i, err = 0;
> -
> -	for (i = 0; !err && i < num; i++)
> -		err = percpu_counter_init(&counters[i], 0, GFP_KERNEL);
> -
> -	if (!err)
> -		return 0;
> -
> -	for (; i > 0; i--)
> -		percpu_counter_destroy(&counters[i-1]);
> -
> -	return err;
> -}
> -
> -void nfsd_percpu_counters_reset(struct percpu_counter counters[], int num)
> -{
> -	int i;
> -
> -	for (i = 0; i < num; i++)
> -		percpu_counter_set(&counters[i], 0);
> -}
> -
> -void nfsd_percpu_counters_destroy(struct percpu_counter counters[], int num)
> -{
> -	int i;
> -
> -	for (i = 0; i < num; i++)
> -		percpu_counter_destroy(&counters[i]);
> -}
> -
> -int nfsd_stat_counters_init(struct nfsd_net *nn)
> -{
> -	return nfsd_percpu_counters_init(nn->counter, NFSD_STATS_COUNTERS_NUM);
> -}
> -
> -void nfsd_stat_counters_destroy(struct nfsd_net *nn)
> -{
> -	nfsd_percpu_counters_destroy(nn->counter, NFSD_STATS_COUNTERS_NUM);
> -}
> -
>  void nfsd_proc_stat_init(struct net *net)
>  {
>  	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
> diff --git a/fs/nfsd/stats.h b/fs/nfsd/stats.h
> index d2753e975dfd..04aacb6c36e2 100644
> --- a/fs/nfsd/stats.h
> +++ b/fs/nfsd/stats.h
> @@ -10,11 +10,6 @@
>  #include <uapi/linux/nfsd/stats.h>
>  #include <linux/percpu_counter.h>
>  
> -int nfsd_percpu_counters_init(struct percpu_counter *counters, int num);
> -void nfsd_percpu_counters_reset(struct percpu_counter *counters, int num);
> -void nfsd_percpu_counters_destroy(struct percpu_counter *counters, int num);
> -int nfsd_stat_counters_init(struct nfsd_net *nn);
> -void nfsd_stat_counters_destroy(struct nfsd_net *nn);
>  void nfsd_proc_stat_init(struct net *net);
>  void nfsd_proc_stat_shutdown(struct net *net);
>  

Reviewed-by: Jeff Layton <jlayton@kernel.org>