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Message-ID: <8b402050-2ed8-4b35-96ec-6672aac35f73@huawei.com>
Date: Mon, 25 Mar 2024 19:56:21 +0800
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Subject: Re: [PATCH] fs: nfsd: use group allocation/free of per-cpu counters
 API
Content-Language: en-US
To: Jeff Layton <jlayton@kernel.org>, 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>
References: <20240325041019.52998-1-wangkefeng.wang@huawei.com>
 <27e0e16b438b67fef765ea03812d6e97646bc1f0.camel@kernel.org>
From: Kefeng Wang <wangkefeng.wang@huawei.com>
In-Reply-To: <27e0e16b438b67fef765ea03812d6e97646bc1f0.camel@kernel.org>
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On 2024/3/25 18:52, Jeff Layton wrote:
> 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.
>>
>> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
>> ---
>>   fs/nfsd/stats.c | 18 ++----------------
>>   1 file changed, 2 insertions(+), 16 deletions(-)
>>
>> 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);
>>   
>>   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;
>> +	return percpu_counter_init_many(counters, 0, GFP_KERNEL, num);
>>   }
>>   
>>   void nfsd_percpu_counters_reset(struct percpu_counter counters[], int num)
>> @@ -99,10 +88,7 @@ void nfsd_percpu_counters_reset(struct percpu_counter counters[], int num)
>>   
>>   void nfsd_percpu_counters_destroy(struct percpu_counter counters[], int num)
>>   {
>> -	int i;
>> -
>> -	for (i = 0; i < num; i++)
>> -		percpu_counter_destroy(&counters[i]);
>> +	percpu_counter_destroy_many(counters, num);
>>   }
>>   
>>   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?

OK, will squash init/destroy and reset into the callers.
>