linux-kernel - Re: [RESEND PATCH v2] sched/fair: Remove check in idle_balance against migration

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Date:   Fri, 16 Mar 2018 10:21:54 -0700
From:   Rohit Jain <rohit.k.jain@...cle.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     linux-kernel@...r.kernel.org, mingo@...hat.com,
        steven.sistare@...cle.com, joelaf@...gle.com, jbacik@...com,
        juri.lelli@...hat.com, dhaval.giani@...cle.com, efault@....de,
        riel@...riel.com
Subject: Re: [RESEND PATCH v2] sched/fair: Remove check in idle_balance
 against migration_cost

Hi Peter,

On 03/16/2018 07:35 AM, Peter Zijlstra wrote:
> On Wed, Mar 14, 2018 at 11:36:47AM -0700, Rohit Jain wrote:
>> Signed-off-by: Rohit Jain <rohit.k.jain@...cle.com>
>>
>> Signed-off-by: Rohit Jain <rohit.k.jain@...cle.com>
> Surely you only need a single on of those.

Oh wow! I don't know how I missed this :) Thanks!

>> ---
>>   kernel/sched/fair.c | 3 +--
>>   1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
>> index 5eb3ffc..569ea83 100644
>> --- a/kernel/sched/fair.c
>> +++ b/kernel/sched/fair.c
>> @@ -8804,8 +8804,7 @@ static int idle_balance(struct rq *this_rq, struct rq_flags *rf)
>>   	 */
>>   	rq_unpin_lock(this_rq, rf);
>>   
>> -	if (this_rq->avg_idle < sysctl_sched_migration_cost ||
>> -	    !this_rq->rd->overload) {
>> +	if (!this_rq->rd->overload) {
>>   		rcu_read_lock();
>>   		sd = rcu_dereference_check_sched_domain(this_rq->sd);
>>   		if (sd)
> I don't think that actually works right on the current tree. In
> particular look at commit:
>
>    31e77c93e432 ("sched/fair: Update blocked load when newly idle")

OK. I see from LKML the code has moved.

However, when I clone from 
https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/
I cannot see the commit.