linux-kernel - Re: [PATCH 1/3] delayacct: introduce delayacct

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Message-ID: <2b2dbd18-b018-7212-8a3c-5d207697709d@gmail.com>
Date:   Sun, 8 Oct 2023 19:03:01 +0800
From:   brookxu <brookxu.cn@...il.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     bsingharora@...il.com, juri.lelli@...hat.com,
        vincent.guittot@...aro.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] delayacct: introduce delayacct_enabled() to simplify
 implement


在 2023/10/8 18:56, Peter Zijlstra 写道:
> On Sun, Oct 08, 2023 at 06:49:36PM +0800, brookxu.cn wrote:
>> From: Chunguang Xu <chunguang.xu@...pee.com>
>>
>> Introduce delayacct_enabled() to simplify the code and make it
>> more concise.
>>
>> Signed-off-by: Chunguang Xu <chunguang.xu@...pee.com>
>> ---
>>   include/linux/delayacct.h | 74 +++++++++++----------------------------
>>   kernel/delayacct.c        |  2 +-
>>   2 files changed, 21 insertions(+), 55 deletions(-)
>>
>> diff --git a/include/linux/delayacct.h b/include/linux/delayacct.h
>> index 6639f48dac36..660e534ce7c4 100644
>> --- a/include/linux/delayacct.h
>> +++ b/include/linux/delayacct.h
>> @@ -94,137 +94,103 @@ static inline void delayacct_tsk_init(struct task_struct *tsk)
>>   		__delayacct_tsk_init(tsk);
>>   }
>>   
>> +static inline bool delayacct_enabled(void)
>> +{
>> +	return static_branch_unlikely(&delayacct_key);
>> +}
>> +
>>   /* Free tsk->delays. Called from bad fork and __put_task_struct
>>    * where there's no risk of tsk->delays being accessed elsewhere
>>    */
>>   static inline void delayacct_tsk_free(struct task_struct *tsk)
>>   {
>> -	if (tsk->delays)
>> +	if (delayacct_enabled())
> This isn't an equivalent change and your Changelog does not clarify.
Sorry, As Patch 2 will convert tsk->delays to object,  we donot need to 
check whether tsk->delays is null or not, so relative code can be simplify.