Re: [PATCH v4 2/4] sched/core: Propagate parent task's latency requirements to the child task

[Parth Shah]

On 2/25/20 12:02 PM, Pavan Kondeti wrote:
> On Mon, Feb 24, 2020 at 02:29:16PM +0530, Parth Shah wrote:
>> Clone parent task's latency_nice attribute to the forked child task.
>>
>> Reset the latency_nice value to default value when the child task is
>> set to sched_reset_on_fork.
>>
>> Signed-off-by: Parth Shah <parth@xxxxxxxxxxxxx>
>> Reviewed-by: Qais Yousef <qais.yousef@xxxxxxx>
>> ---
>>  kernel/sched/core.c | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
>> index 377ec26e9159..65b6c00d6dac 100644
>> --- a/kernel/sched/core.c
>> +++ b/kernel/sched/core.c
>> @@ -2860,6 +2860,9 @@ int sched_fork(unsigned long clone_flags, struct task_struct *p)
>>  	 */
>>  	p->prio = current->normal_prio;
>>  
>> +	/* Propagate the parent's latency requirements to the child as well */
>> +	p->latency_nice = current->latency_nice;
>> +
>>  	uclamp_fork(p);
>>  
>>  	/*
>> @@ -2876,6 +2879,7 @@ int sched_fork(unsigned long clone_flags, struct task_struct *p)
>>  		p->prio = p->normal_prio = __normal_prio(p);
>>  		set_load_weight(p, false);
>>  
>> +		p->latency_nice = DEFAULT_LATENCY_NICE;
>>  		/*
>>  		 * We don't need the reset flag anymore after the fork. It has
>>  		 * fulfilled its duty:
>> -- 
>> 2.17.2
>>
> 
> LGTM.
> 
> latency_nice value initialization is missing for the init_task.

good catch. Will add that part too. Thanks for pointing out.

- Parth

> 
> Thanks,
> Pavan
>